So I thought it would be kinda neat to start a thread that maybe could benefit everyone that wants to tune.

If your gonna tune one of the first steps is to datalog.
A great site to start with for some free datalog software can be found here. You'll also find directions on that page to build your own OBD1 connector

http://winaldl.joby.se/

You can also find free tuning software at
tunerpro.net

trial software, they also carry datamaster
tunercat.com

Tunercat and datamaster is what is most often used when your getting a prom done by a mailorder company

If you prefer to tune yourself then you may need to look into burning your own proms.
Most common place for us guys to get the prom burning equipment and chips are through
moates.net

Hopefully this will get us all started on a thread that can end up with some good information and a place to discuss the early stages of tuning.

Getting to know the parts

INPUTS
TPS- throttle position sensor
CTS- coolant temperature sensor
MAT/IAT- Air Inlet temperture
MAF- Mass Air Flow Sensor
MAP- Manifold Absolute Pressure
Crank/Cam Position Sensor
FRP - Less common Fuel Rail Pressure
Oxygen Sensor
Knock Sensor

OUTPUTS
Fuel Injectors
Fuel Pump
Ignition
IAC- idle Air Control

slrvette---This is very good info and a very good idea to start a thread like this. I just got my first Vette this past March 29th. A 2000 6 sp C5. I am interested in doing some mods in the future but for now I am just having fun and learning new things. I hear a lot of talk about doing mods and then "getting a tune" but no one ever elaborates on how to do this or what resources are available. This information helps a great deal. Please post more info if you got it. My ear is bent. :talk011:

Thanks for starting this thread Ed even though the ugrades for the Vette have been pushed back due to the new project. I will follow and bookmark this.

Very cool, Ed. I just got the EBL installed today and did about 10 VE learns, seems to run pretty good so far. I really don't know what kind of changes I need to make when it comes to the SA tables, but I'm researching and learning. My BLM's are starting to shape up and by golly I'm starting to feel more comfortable with tuning.

Cool, I'm glad you guys are into this. I thought maybe it could be something to help all of us.
And how could I forget to add dynamicefi's ebl/flash ecm.
The VE learns are nice for sure. I've found however that with a more modded engine they help but just don't get you where you want to be. One reason I thought this thread could help up all.I was thinking maybe the first thing we could discuss would be the function of each Input sensor. If were not certain of what the sensors do and there parameters then it will make looking at your datalog or making an adjustment to your tune that much more difficult

Is this a theoretical discussion on tuning? Are we talking stock ECUs or ALL ECUs?

There is commonality between all ECUs so perhaps we stick with that.

The Stock ecu is a great ECU. the issue is there is SO MUCH detail, it's hard to figure out sometimes.

Much more granular than any aftermarket ECU.

I am working to eliminate the stock ECU all together.

ON my car I am still controlling Speedo and TQ Converter lockup. I ordered a box from Dakota DIgital which will take care of the speedo and cruise control issues, and I will set the TQ Converter to lock up in OD every time as opposed to using a relay to do it at a certain speed.

Additionally, I used a fan thermostat in the driver's side head which goes ON at 200 and OFF at 180, bypassing the ECU. That was VERY easy, it works great, and still has a factory look.

There's a lot of things that can be done in a complete replacement for the ECU, a hybrid solution, or a complete stock situation.

Lots of ways to go. I think the FIRST place to start is to look at your combination and determine which route you want to take. I am going for complete replacement. When you start digging into it, there's really not much the stock ECU does outside of fuel/spark that can't be over come.

Is this a theoretical discussion on tuning? Are we talking stock ECUs or ALL ECUs?

There is commonality between all ECUs so perhaps we stick with that.



You got it!. There common ground between all tuning. VE,PE,AE,SA and tons more. Just thought maybe since were all doing it we'd get a good discussion going the help each other out. I'm gonna post about the sensor's later today so that should have good info as well. Or any of you other guys feel free as well.

TPS- tells the ecm exactly where the throttle blade is at all times. idle,cruise,acceleration,decelleration. So its pretty important.
Typical volt settings for the TPS
TBI- key on engine off is .525
TPI- key on engine off is .545

CTS- monitors the temperature of the engine

MAT/IAT- monitors typical air temperature coming into the engine.

MASS AIR FLOW- monitors the amount of air coming into the engine

MAP- monitors the pressure within the intake (manifold)

CRANK/CAM sensor- monitors engine speed and second indicates actual rotational position but is more critical to sequential systems.

FRP-not often used but is self explainitory. Monitors fuel rail pressure

O2 - corrects for errors between desired and delivered a/f ratios.

Knock sensor- detect the presence of detonation

WB02- like the O2 corrects for errors between desired and delivered A/F ratios... however is much more accurate than the 02.

I also found a good link to use as a tuning glossary

http://www.innovatemotorsports.com/resources/tuning-a-z.php

This is a great idea! :thtoppoints:

SLVR, not to be a PIA but you left out the IAC....didn't see that in the mix...


OOPS never mind, saw it under outputs.

I think the place to start is:

1. What is the goal of tuning
2. What types of tuning. WHY? Dnyo vs. street tune.

SLVR, not to be a PIA but you left out the IAC....didn't see that in the mix...


OOPS never mind, saw it under outputs.

I think the place to start is:

1. What is the goal of tuning
2. What types of tuning. WHY? Dnyo vs. street tune.

Your always a PITA...LOL just kidding
I thought by giving brief explanations first of Inputs and outputs would be best. To many times all this is skipped. You get into the MAP and don't understand what your seeing, Then you try and research it on the net and it gets very frusterating for the DIY tuner... myself included.

I was hoping that maybe one of the injector vendors could jump in an explain the injector and the importance of it. Why lb/hr are important,BPC,BPW..etc.

Once the DIY tuner understands those items then we can move on to datalogging,goals, and some actual screenshots of some SA and VE MAPs. At that point the tuner will understand what they are looking at.

Just the type of thoughts I was having about it.

Your always a PITA...LOL just kidding
Everyone needs a hobby....:D

I thought by giving brief explanations first of Inputs and outputs would be best. To many times all this is skipped. You get into the MAP and don't understand what your seeing, Then you try and research it on the net and it gets very frusterating for the DIY tuner... myself included. [/quote]

I will agree. Definitions are key.

I was hoping that maybe one of the injector vendors could jump in an explain the injector and the importance of it. Why lb/hr are important,BPC,BPW..etc.

Done, next post.

Once the DIY tuner understands those items then we can move on to datalogging,goals, and some actual screenshots of some SA and VE MAPs. At that point the tuner will understand what they are looking at.


I'd like to get into that but my time is limited today. I'll try.

I was hoping that maybe one of the injector vendors could jump in an explain the injector and the importance of it. Why lb/hr are important,BPC,BPW..etc

First, there's two kinds of injectors, high impedance and low impedance.

The reason for this as flow rates increase and fuel pressures reach 5 bar on newer stock motors such as the Mopars, the high impedance injectors could not over come the pressure and volume necessary therefore, had to go low impedance, resulting in more current across the solinoid.

Most high impedance injectors end about 50-60 lbs, after that you will typically see low impedance. That being said, Injectors Plus is one of two vendors in the country that sell 160-200LB high impedance injectors.

SO...the impedance is typically dictated by the ECU you are running. If you are running an ECU that supports high impedance (like the OEM ones) you are limited to about 60 lbs. If you have a high impedance system and need low impedance injectors, we can supply drivers that you will have to add to accept low impedance injectors on that ECU.

Now sizing injectors is a bit of a science, and a bit of a skill. Sure anyone can pull a flow rate out of their *** and say make it fit XXXX application, however understanding WHY that flow rate is important is as important as getting it right.

I see a TON of misinformation flying around the internet about how to size an injector. I see too many people buying too small an injector for their application. Lots of bad recommendations out there.

We have a calculator on our site that addresses sizing injectors:

http://injectorsplus.com/calculation-tools.asp

This provides a basis of where to start looking

If you size the injectors too big, it will be hard to tune in your idle speed. If you size them too small, you will run lean at top and do thinks like melt pistons and stuff. Just got a set in from someone who did that.

One note I'd like to make here is that there's only a handful of manufacturers of injectors such as Bosch, Seimans, Delphi, Rochester, Lucas, Denso.....all other injectors are just a variation of these with a private label on them. Even if laser engraved.

Now the issue of correct sizing also addresses weather you have forced induction or naturally aspirated motor. That is where BSFC comes into play. But we'll stick with NA for now.

To explain WHY sizing is important as it relates to the size and HP of your motor requires you to understand the basic workings of the internal combustion engine and something called VE or VOLUMETRIC EFFICIENCY.

VE means when the piston comes down during the intake stroke, how much of that cyl is going to fill with air. Now most of the time if you get max 80% VE your doing well. This is reflected in the HP per CI argument we hear from time to time.

Competitions such as Engine Masters you may see VE as much as 110% but that is VERY hard to do and can only be done under very controlled circumstances... the major problem is port velocity required to get to that over 100% efficiency is not achievable. The ports "stall" or lock up at .6 MACH and typically requires air speed faster than that to get over 100%. That's why small port heads and big flow numbers don't work if your spinning it up to high RPMs and tend stop making power, falling on their face at lower RPMs than larger ports with equal or less flow, and therefore making less power. But I digress.......

Great info guys!

Now think about what is happening, you have VE in filling a specific size cyl with a specific amount of air and fuel. This is called FUEL SUSPENSION. Again, this is more reliant to intake runner design which allows the droplets of fuel to remain a mist and not condense or consolidate within the fuel path.

So your question is, who gives a rat's butt....

It is important to understand those 10,000 foot theories in order to get a better grasp on what you are trying to accomplish with a tune.

The optimum most efficient use of fuel is called stoichiometric reaction which leaves a 14.7:1 ratio of oxegen to burned fuel. The goal when tuning is to try to keep with that number.

Now that rule is not hard and fast. In my car for example I idle lean, at 15-16 AFR. WHY? The cam likes that. Under acceleration or power requirements you should expect to see 11.6-12.3 for optimum power. at WOT it shouldn't drop below 11.

The lower the number is, the richer the mixture is.. So 17 is leaner than 13.

now, with all that out of the way, the question is......

WTF does this have to do with tuning?

Well, to understand what you are trying to achieve with the tune, you need to understand the circumstances that come to play when trying to tune. How the sensors work, and what relationship they have to the end goal.

So let's look at what the end goal is.

The end goal, in any tune, is to get the AFR correct so the car responds the way you want under particular conditions created. That's where the sensors come in, and all the sensors are related to each other.

So during the tune what you will be doing is considering the size of the motor, the VE. Try to figure out how much fuel is required at a particular VE, and tell the computer to give it that much. The variable that delivers fuel is called PULSE WIDTH or how long a particular injector stays open and continues to deliver fuel. Now, the motor requires a specific amount of fuel to maintain the correct AFR under given conditions. The smaller the injector, of course, the longer the pulse width. Of course, the PW is measured in MILLISECONDS. So a 20 lb injector will require twice the time as a 40LB injector. It's that simple.

Now, this is a GROSS over simplification of the process, and by no means do I expect a text book to be written based on my ramblings. HOWEVER, I think without a basic understanding of how fuel systems work, it's hard to even begin to discuss how to tune a car.

SO.....with this basic understanding, the next step is to understand what the sensors do and how they relate to each other when determining how much fuel to deliver and under what circumstance.

WHEW! Can someone read that over and tell me where I got lost?

I see too many "tuners" who don't understand what they are tuning or how the motor works tuning cars. It's not REQUIRED information but I believe if you understand the underlying theories about how this stuff comes together, the mystique of tuning kinda fits into place. It's not all black magic. It's not hard to do, but without experience and knowledge it's hard to do WELL. So our goal is to take the physics of delivering fuel into a combustion chamber and understand what that means to the ECU based on the sensors and conditions it is given, and ultimately, how much fuel needs to be deliered based on the feedback of those sensors.

All these sensors are, are indicators of engine conditions so the fuel can be put in or taken out. WHY do you put less fuel in a hot one vs. a cool one? WHY does the amount of vacuum change the amount of fuel you give. THOSE are the basis to understanding tuning, before you pick up a laptop.

thanks.

Take a deep breath John...........now exhale. Feel better?....lol.:

Take a deep breath John...........now exhale. Feel better?....lol.:

HA! In through the nose, out through the mouth!

Someone.....quick get me a bag.

I'll pause here instead of dumping too much info.

Next up, sensors, as SLVR talked about and how each is related to the other. Inputs first. Then outputs.

Exactly!
The only output that hasn't been explained yet is the IAC.
Anyone?

I think that this is coming out perfect. Very simple and basic for the beginner so you don't feel overwhelmed the first time you look at the datalog like I did!...lol
Almost ready to datalog?

Exactly!
The only output that hasn't been explained yet is the IAC.
Anyone?

I think that this is coming out perfect. Very simple and basic for the beginner so you don't feel overwhelmed the first time you look at the datalog like I did!...lol
Almost ready to datalog?

IAC...as it says....IDLE AIR CONTROL

When you make a mixture more rich or lean it effects the idle. By opening the throttle plates, the idle can go up and down if you add more air in, or take air out of the mixture.

The car has to idle at a particular RPM under numerous conditions. The IAC does that.

For example, if your in neutral, the load on the engine is zero and the idle will be what it is.

What happens when you turn on the air conditioning? The computer know the idle should be say 1000 RPM. So it makes the idle 1000 RPM. When you go from Neutral to gear, the motor steps down again, so the IAC brings the idle back UP to where it's supposed to be.

How does it do that? Well picture a screw inside a pipe. The screw has a cone shaped head called a Pintle. The pintle fits inside the pipe which is also cone shaped on the inside. So the screw goes in and out of this cone shaped tapered recess in the pipe, depending on the idle.

So the ECU is looking at the INPUTS, sensors, and the RPM and saying......HMMM....the RPMs are high/low based on the input of the sensors I need to add/subtract air.

There is a hole in the throttle body which is opened or closed by the IAC moving in or out. When the IAC retracts the pintle the hole is opened, allowing more air into the system, raising the RPMS. When it is closed, the mixture is richer.

So it, the ECU, backs out, or runs in, the IAC until the idle meets the pre programmed designated idle. Once there, it stops.

Now think about what is happening, you have VE in filling a specific size cyl with a specific amount of air and fuel. This is called FUEL SUSPENSION. Again, this is more reliant to intake runner design which allows the droplets of fuel to remain a mist and not condense or consolidate within the fuel path.

So your question is, who gives a rat's butt....

It is important to understand those 10,000 foot theories in order to get a better grasp on what you are trying to accomplish with a tune.

The optimum most efficient use of fuel is called stoichiometric reaction which leaves a 14.7:1 ratio of oxegen to burned fuel. The goal when tuning is to try to keep with that number.

Now that rule is not hard and fast. In my car for example I idle lean, at 15-16 AFR. WHY? The cam likes that. Under acceleration or power requirements you should expect to see 11.6-12.3 for optimum power. at WOT it shouldn't drop below 11.

The lower the number is, the richer the mixture is.. So 17 is leaner than 13.

Something I wanted to comment on here. Fuel suspension is important because an intake/head that promotes better fuel suspension will require different tuning parameters than a head/intake where the QUALITY of the air flow sucks.

That is why I say it's not all about flow numbers for heads, but the quality of the air that is delivered.

The ability to suspend more fuel in the air will result in more power and different tuning nuances.

THIS IS IMPORTANT!!!!

The reason is because I see a lot of people ask "what size injectors do you have".....and responses that say....I have XXX on my motor.

Well, if their heads have BETTER QUALITY NOT QUANTITY of air flow, you will need to deliver LESS FUEL to get better results. It CAN effect both the tune, and the size of the injectors. That's why sizing isn't hard and fast. But the ECU allows you to tweak that, as does your fuel pressure.

Each combination is unique.

I bought up another dynamic here in the last post. Fuel pressure.

Fuel pressure is important in tuning because it will effect how you tune as it will effect the flow of the injectors.

This is exactly why INJECTORS PLUS is more than injectors. All these elements come together to result in the correct FUEL DELIVERY SYSTEM. As I had said in the past injectors are like gum at the checkout line, the crap next to the mints and national enquirer while you stand behind someone with 25 items in the 10 item express lane. That's why you don't see Sea Foam or Injector Cleaner on my site, Autozone has it you can get it there, we stick to the meat and potatoes of how this stuff works.

There are serious considerations to the entire system when building a high performance motor, and they ALL effect the tune.

For example using a fuel pump that has -10 AN in and -10 AN out may have the tendency to run dry or experience cavitation. This will result in poor fuel pressure and effect the tune. The solution, use -12 in and -10 out a lot of times.

Which regulator you choose can determine the performance of the system. It has to be matched to the pump you're running. Just had a guy running a carb regulator on an EFI motor and wondering why it won't work. This again, WILL EFFECT THE TUNE.

Fuel pressure too will dictate what injectors you use. For example, I have sold Seimans injectors for very high performance applications, and very expensive motors. I have no problem with that. These are motors that run $50-70K just for the motor. Seimans are good injectors.

On the other hand I have a customer who has a forced air IMPALA he runs on the street not worth $15K. If I had my preference I'd put him into BOSCH. WHY? The Seimans are a great injector, but under FP of 60 pounds or so and up, the pintle vibrates and they fail. He melted a piston.

What we did was open his 60s to 80s when we rebuilt them to allow him to get the tune and lower his fuel pressure to ensure safety.

I think my point is, as evidenced by IP's tag line here "HIGH PERFORMANCE FUEL DELIVERY SYSTEMS" the tune is the LAST STEP in dealing with what you're going to require to get the car to run right, not the first.

Although injectors are that "gum" it's good to understand which product and which size is the right fit and the implications of choosing one injector over another for any given application. It's far more than "application and flow please".....that's where advice based on experience and knowledge can save you a lot of time and headaches in your tuning.

Flow matching...something else that effects a tune.

We hand match every set of injectors that leaves our shop. We buy a box of 300 injectors and the manufacturer says "flow matched" on the box. Don't believe it.

There is "flow matched" and "FLOW MATCHED". Some vendors will tell you a set of injectors is flow matched simply because it says so on the box. They reach in and grab a bunch and toss them in the bag and out the door we go.

Well, our experience tells us that whatever is printed on the box is not necessarily the truth. We hand pick every single injector we sell and flow match ever set on the bench before they leave the shop.

Why is this important? Well first, many of our customers have VERY expensive motors.

Second, if you don't have a truly flow matched set, it makes the car MUCH harder to tune. Inconsistencies in injectors can screw with the AFR the O2 sensor is picking up and you can wind up with some lean and some rich cylinders.

I can't afford to have customers blowing up motors, and the fact of the matter is the slight increase in cost for a truly flow matched set, will be off set by the time you save trying to tune, by a long shot. Professional tuners can save 2 hours on a tune between a flow matched set and not. Not MY numbers, theirs.

Think about what that means to the amateur.

BTW, SLRV, all this is stream of consiousness. I am writing off the top of my head with no planing or fore thought.

If it's disjointed or needs re arranging, feel free.

I apologize for digging so far down the rabbit hole, but I think it's required to understand the SYSTEM before talking about how to tune it. Bottom line tuning is the last part in fuel system design and without a basic understanding of the elements that get you to that tuning, it's harder to understand.

if you think of tuning as simply trying to get the right AFR under certain loads, temps, timing conditions, it's not all that magical.

Someone couldn't sleep last night...:beer-fresh:

Someone couldn't sleep last night...:beer-fresh:

NOPE I couldn't.

Been up since 3AM!

What I didn't mention was the cam will effect a lot of this, for the sake of argument we can assume using a cam without a lot of overlap. We can keep this discussion to a fairly mild cam.

And one last comment before we get into how the inputs effect the outputs is that some of the theory we will discuss is general tuning. The stock ECU is very granular and incorporates parameters such as AC and speed. Aftermarket ECUs typically control spark and fuel only hence, being much simpler to tune. This is probably due to the advances in technology than shortcomings of aftermarket ECUs. GM designers had to build an ECU which would do particular things under every possible condition, from the heights of Colorado to the swamps of Florida. Typcially our cars stick in our general area, so this is less important. Not to mention GMs requirements to meet EPA laws. You won't see things like injector decay in an aftermarket system.

More please.....:goodpost:

More please.....:goodpost:

Sorry, I'm learning this as I go a bit too. SV and I mentioned on PM we need to get this going again.

If anyone sees I say something off, CORRECT ME.

OK, the basis of all tuning is the IDLE. If you can't get the idle right, the rest is kinda meaningless.

To do this remove the IAC from the air circuit, cover the IAC hole in the throttle body with duct tape. Dial in your idle from that point.

Then reconnect the IAC and remove the tape.

the idle should adjust from there.

At this point when you put it in gear, or start the AC, the car will SURGE then level down to where it is supposed to be idling. MOST ECUs have an adjustment for that condition, how high it will surge.

There is something called a "LEAN STUMBLE" if you make the car idle too lean. Idle air fuel ratio is relative to the cam. Some like 13.X others can go to 15.X.

If the idle is too lean, when you come off idle the car will want to stall, and studder.

MOST ECUs have an adjustment for that so that it works as an "accelerator pump" to push gas as you are just off idle. There is a setting there.

So the trick is to get the idle to a point where it's as lean as you can go, but still adjust the "accelerator pump" feature so that you can leave the stop light without studdering.

This is very basic, very elementary stuff. There are people better than this than I am.....I'm sure they can chime in...:D

I'm gonna get back on this as well. I've been swamped with work.

I really like the way you connect all these thing together, a nice walk through on how the different parts work together. It gives me a greater idea of whats going on.

Thanks

I really like the way you connect all these thing together, a nice walk through on how the different parts work together. It gives me a greater idea of whats going on.

Thanks

Thanks for the comment, makes it worth my time to write.

Flow matching...something else that effects a tune.

We hand match every set of injectors that leaves our shop. We buy a box of 300 injectors and the manufacturer says "flow matched" on the box. Don't believe it.

There is "flow matched" and "FLOW MATCHED". Some vendors will tell you a set of injectors is flow matched simply because it says so on the box. They reach in and grab a bunch and toss them in the bag and out the door we go.

Well, our experience tells us that whatever is printed on the box is not necessarily the truth. We hand pick every single injector we sell and flow match ever set on the bench before they leave the shop.

Why is this important? Well first, many of our customers have VERY expensive motors.

Second, if you don't have a truly flow matched set, it makes the car MUCH harder to tune. Inconsistencies in injectors can screw with the AFR the O2 sensor is picking up and you can wind up with some lean and some rich cylinders.

I can't afford to have customers blowing up motors, and the fact of the matter is the slight increase in cost for a truly flow matched set, will be off set by the time you save trying to tune, by a long shot. Professional tuners can save 2 hours on a tune between a flow matched set and not. Not MY numbers, theirs.

Think about what that means to the amateur.

I just left a shop that does hundreds of injectors with us a month. He deals mostly with imports, has a 20 car backup and six on the lifts. He's well known in this area and is well respected. NOT a rice guy, but a real performance guy who does imports.

Anyway, all the injectors we sell are FLOW MATCHED. Sure, we aren't going to be the cheapest, just the best. And the reason we do this is because it is far easier to tune.

The guy JR, who owns the shop, was telling me yesterday that he got a set of injectors before using us that weren't flow matched, he ripped them out because he couldn't get the car tuned, and this is a guy who does this on a daily basis, a real expert.

So as far as tuning is concerned, I thought this a validation story to spend a few extra bucks on flow matched sets. It will make life a lot easier for you down the line.

We got the general idea of whats going on with some inputs and outputs so far. Naturally the thread isn't intended to start a tune from scratch and build a .bin. What we want to do is assume that the car were tuning is something thats already existing and basically running or you've just done some mods on it.

Before you want to do anything with the tune we need to see whats going on with the engine. So we need to start with a datalog. This records and you can analyize whats going on with those inputs and outputs.

Doesn't matter which datalog program you decide to go with they basically all give you the same information but may look a bit different.

Here's a screenshot of my datalog program

http://i60.photobucket.com/albums/h5/slvrvette/gar1.jpg

So what your looking at is the basic infomration of your inputs and outputs.

RPM,MAP,TPS,SA,CTS,IAT,Injector PW,GMS sec,
INT,BLM,WB02,IAC

Don't expect to now everything with one datalog. Unfortunetly you'll never stop datalogging as long as your tuning.

Here's another look at my datalog program. this is what I have up while driving and it gives me an overall look as to whats going on. Theres more screenshots I can show you and will later. Just trying to give you an idea of what the datalog is showing. The program I use also allows me to playback my datalogs. I can bring the computer inside and play it back as if it were live
http://i60.photobucket.com/albums/h5/slvrvette/wud.jpg

Great Reply. Let's take a look at what is going on with ed's car and see if we can make some determinations.

1. He's at idle
2. He's pulling about 55 KPA which indicates light load on th emotor.
3. He's idling a little on the lean side which is no biggie
4. Looks like he put it in gear around time stamp 00:00:35 and the IAC compensated
5. He's in open loop. (that is why the BLM is pegged at 128)

So what does all this mean?

To me, looks like he has a happy idle at a decent AFR with a working IAC.

Not ALL ECUs program this way. I'll get some screen shots of mine tonight so you can see what is happening.

That is a good place to start the process.

Exactly. All ECU's are different but you will have the same basic information.
You can tell what state the engine is in just by looking at a few simple things.
RPM
Open Loop or Closed Loop

What I have found out the first thing you need to do once you start datalogging is pay attention to your inputs. Make sure they are all working correctly. The datalog program will only work as well as the information that its been given.

To give you an idea of how to look at this .bin lets try this:

First line of the datalog
825 RPM
MAP 56
Say you want a bit more fuel because the AFR is 16.6

Open you .bin in your editor, find the table that is used for the VE. In my case its called VE Low Speed. here's a shot of it. I've highlighted the 825 RPM area @ about 56 Kpa

http://i60.photobucket.com/albums/h5/slvrvette/Avatar/teach3.jpg

Let say I want to bump my fuel a bit. You can do it one of two ways in my case. Either type in a new number and go with that or (what I do) is pull up the graph. Select that same area 825 RPM 56 Kpa
http://i60.photobucket.com/albums/h5/slvrvette/Avatar/teach1.jpg
Then pull it up. Naturally this is an extreme but wanted to give you a good idea of what it does
http://i60.photobucket.com/albums/h5/slvrvette/Avatar/teach2.jpg

Little bit off the subject but what do ya think about shaving the heads. Bring the compression in my 93 up to say 11:1, or maybe a little higher. Would that change my fuel requirements?

Little bit off the subject but what do ya think about shaving the heads. Bring the compression in my 93 up to say 11:1, or maybe a little higher. Would that change my fuel requirements?

Don't think your off topic at all. IMO I think that once you make your change and to get the best performance out of your engine (if thats was your looking for), then yes. A tweak to the tune would be in order

This is a great thread and I'm learning a lot about tuning. One question I do have is can someone expand on this?
To do this remove the IAC from the air circuit, cover the IAC hole in the throttle body with duct tape. Dial in your idle from that point.
How do we dial in the idle from that point? It looks like the IAC controls the idle and the ECM controls the injectors and timing. Aside from plugs and wires, isn't all the control given to a better faster smarter computer?

This is a great thread and I'm learning a lot about tuning. One question I do have is can someone expand on this?

How do we dial in the idle from that point? It looks like the IAC controls the idle and the ECM controls the injectors and timing. Aside from plugs and wires, isn't all the control given to a better faster smarter computer?

Use the screw on the throttle body to move the plate in and out, or move the idle up and down. Set it where you want, then reconnect the IAC and take the tape off the holes.

Use the screw on the throttle body to move the plate in and out, or move the idle up and down. Set it where you want, then reconnect the IAC and take the tape off the holes.

Exactly, when I "dialed" it in on mine. I disconnected the wire to the IAC set my idle using the stop screw on the TB linkage. Set that to 800 RPM.
At that point I plugged the IAC back in and my RPM dropped a little bit more. think to about 700 RPM.
I had my laptop setup and in my tuning software set my idle to where I wanted it. I opened up my datalog program and while watching the IAC counts I "tweaked" the idle adjustment screw until I got the counts I wanted at idle.

So lets say my IAC counts on this start up were only 5 and I wanted 20. I turned the screw very slightly until my counts on the datalog screen where 20. Then I was done.

Thanks guys. This helped me out because I think the Vette is idling to high. I'll try to bring it down this weekend. I'm pretty new to this Corvette stuff so this is a great learning experience for me. I don't want to ask to many questions because this may be covered latter.

The program you guys are using is called WhatsUp? Correct? Why do you prefer whats Up to WinALDL and where can you get the application Whatsup? I did do a quick internet search and nothing came up under the Whatsup application with obdii in the search engine.

I believe yours is OBD I, not II...

The program you guys are using is called WhatsUp? Correct? Why do you prefer whats Up to WinALDL and where can you get the application Whatsup? I did do a quick internet search and nothing came up under the Whatsup application with obdii in the search engine.

WinAlDL is a datalog program. You can find a link to that within the first few posts of this thread

Whats Up is another type of datalog- that came with my new ECM. It can't be used with any other type of ecm. Only the EBL/Flash from dynamicefi.

DataMaster is another type of datalog. theres a link for that as well in the beginning.

I know .... a bit confusing.

on the topic of injectors to me there is a lot more to the concept of injector flow than flowing at a static pressure of 43.5 or whatever psi. thrown at the injector.
In tuning and application the most critical area of the injector pulse width occurs below 6ms. and .02 fuel mass (gr.). When comparing injectors or doing swaps this is were the differences between injectors can be seen.
If swapping from an early type ev1 to the later type ev6 that flow the same lb. rating @43.5 the result using stock gm offsets is an air mass calculation that is approx. 12% off all the time. This 12% airmass error can get carried over to the idle control strategy, making it that much more difficult for the ECM to precisely control idle speed with the IAC motor or electronic throttle control system. The solution is to command the ECM the new injector characteristics that will result in an injection time of 3.1ms in order to deliver the fuel mass target of 0.010g to the cylinder. This means giving the ECM more info than just the offset and linear flow rate. The same would apply to using higher than rated psi for an injector. The truth is that the increase in
pressure also affects both the opening delay and the nonlinear flow region of injection.
Ford racing has been kind enough to make there injector information public. The problem for most here is using the ford logic/description of "intercept of the high slope" low slope" etc. is than converting it into gm description.

on the topic of injectors to me there is a lot more to the concept of injector flow than flowing at a static pressure of 43.5 or whatever psi. thrown at the injector.
In tuning and application the most critical area of the injector pulse width occurs below 6ms. and .02 fuel mass (gr.). When comparing injectors or doing swaps this is were the differences between injectors can be seen.
If swapping from an early type ev1 to the later type ev6 that flow the same lb. rating @43.5 the result using stock gm offsets is an air mass calculation that is approx. 12% off all the time. This 12% airmass error can get carried over to the idle control strategy, making it that much more difficult for the ECM to precisely control idle speed with the IAC motor or electronic throttle control system. The solution is to command the ECM the new injector characteristics that will result in an injection time of 3.1ms in order to deliver the fuel mass target of 0.010g to the cylinder. This means giving the ECM more info than just the offset and linear flow rate. The same would apply to using higher than rated psi for an injector. The truth is that the increase in
pressure also affects both the opening delay and the nonlinear flow region of injection.
Ford racing has been kind enough to make there injector information public. The problem for most here is using the ford logic/description of "intercept of the high slope" low slope" etc. is than converting it into gm description.

HEY MICK, your name just came up in another thread. http://www.smokinvette.com/corvetteforum/showthread.php?t=42587

I hate to hijack, but I gave up with the stock ECU.. Not that it isn't a better solution if you know what you're doing, it's just SOOOO HARD these days to find someone who does.

I am carrying a line by Motorvation. This is TJ Tracey's company :

http://www.motorvation.tv/images/72dpi/tuning.jpg

TJ was with Hypertech for years and Mike, was the primary tech guy for FAST for years. These guys know their stuff. It's what they run on their cars, both track and hot rods. Mike is running it on a mild Ford Galaxy that he uses for a street cruiser.

I put one in my car as I just simply couldn't get the stock ECU dialed in. I attribute that to 3 things:

1. Lack of experience
2. Complexity
3. Lack of local support that has been doing it on the on going basis

It's running much better now with the new ECU and has allowed me to actually UNDERSTAND tuning and not just get frustrated.

on the topic of injectors to me there is a lot more to the concept of injector flow than flowing at a static pressure of 43.5 or whatever psi. thrown at the injector.
In tuning and application the most critical area of the injector pulse width occurs below 6ms. and .02 fuel mass (gr.). When comparing injectors or doing swaps this is were the differences between injectors can be seen.
If swapping from an early type ev1 to the later type ev6 that flow the same lb. rating @43.5 the result using stock gm offsets is an air mass calculation that is approx. 12% off all the time. This 12% airmass error can get carried over to the idle control strategy, making it that much more difficult for the ECM to precisely control idle speed with the IAC motor or electronic throttle control system. The solution is to command the ECM the new injector characteristics that will result in an injection time of 3.1ms in order to deliver the fuel mass target of 0.010g to the cylinder. This means giving the ECM more info than just the offset and linear flow rate. The same would apply to using higher than rated psi for an injector. The truth is that the increase in
pressure also affects both the opening delay and the nonlinear flow region of injection.
Ford racing has been kind enough to make there injector information public. The problem for most here is using the ford logic/description of "intercept of the high slope" low slope" etc. is than converting it into gm description.

I bought this up in another thread regarding another company selling injectors we tried, and decided they wouldn't work. You CAN get things to work this way, but with the right info it is more effective. If we make a custom injector, 99% of the time, it works fine. My partner has been doing this for 20 years. HOWEVER, there are those times where you can't get a car to idle, and that modification is a failure. And you're right about not having the slope info and such to try to tune that out.

There is a ton of stuff to know about modded injectors, however, if you're using a wide band,and tuning to the AFR at a given point, doesn't that all just go away, assuming all the points are tuned to that AFR and have the proper amount of timing?

Also what's your opinion about MAP vs MAF as it relates to this information?

The MOTORVATION system is set up before it leaves the factory for the basis of your car. They set the injector flow, RPM range, etc.. etc... etc... By doing this a lot of nuance is buried, and this is done by design to keep it simple. Because you don't see it here, does not mean it's not capable, just means it was buried from the UI so you can more eaisly tune.

Here's how the Motorvation tunes, and why I decided to use it. The FUEL Screen.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs062.snc4/34446_10150206406165444_429364290443_13442422_1540 704_n.jpg

This is the primary tuning screen, a box shows up where you are running. The information regarding the engine is in the box that is always on top.

What you see in the screen is the PULSE WIDTH.

You want it richer, you multiply it by 1.XX

If you want it leaner by .XX

It is adjustable to 2 decimal points, many systems only one. So it is more granular.

The pulse width is adjusted until you get the desired AFR you are seeking. Pretty simple.

You can select a range of numbers, single box.

Also on this screen you can adjust the fuel bump, for example when you put on the AC or put it in gear, the RPM will go down and come back up. You can control the response time of the IAC and the fuel delivery as to how fast the pump reacts when you put your foot down.

The choices are multiply range, fill, interpolate using formulas in the software either vertical or horizontal. You simply drive and adjust the number in this box to the get the desired AFR. The software guides you as to where you're at, so it's easy to follow. The box where the car is operating turns red.

With their system, the second screen is pretty self explanatory, SPARK. You set your timing curve here.

http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs022.ash2/34446_10150206406175444_429364290443_13442424_3925 644_n.jpg

On the bottom you will see starting timing, you just throw that in there. And a rev limiter.

That's easy enough.

O2 sensor screen sets target AFR. You can see on the bottom it allows idling in open loop and the parameters are set for when closed look kicks in. TPS position, RPM, and temp.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs042.snc4/34446_10150206406160444_429364290443_13442421_3246 861_n.jpg

The IAC screen sets your idle:

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs042.snc4/34446_10150206406170444_429364290443_13442423_7475 178_n.jpg

Simple...the RPM rev limit is one element of taking it out of open loop. if you exceed that limit, you're in closed loop.

The offset screen changes fuel delivery on the global basis by either water or air temp. So under certain conditions if you want it leaner or richer you can dial that in.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs182.snc4/37445_10150206405790444_429364290443_13442402_2429 434_n.jpg

The system will support up to a 5 bar sensor. It says 3 on the bottom, but can be unlocked for 5.

And finally single or dual stage NOS settings:

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs042.snc4/34446_10150206406155444_429364290443_13442420_7971 120_n.jpg

Don't think too many here are worrying about that.

Mick will tell verify, he's been giving me help for 2 years trying to get my tune right. The guy who I had helping locally, I think was over his head.

The Motorvation ECU was tuned in 3 hours for a perfectly good street tune (just starting is a little hard but I only get one shot a day at that).

Faster chips, better technology, and native PC interface have made tuning MUCH easier. The stock ECU is a lot more granular, however, it is pretty complicated.

I understand the theory of the stock ECU, putting it into practice on a stock ECU was REALLY time consuming and I just wanted to DRIVE the car. Now it is running stronger than it ever did with the stock ECU and doesn't have all the pops on deceleration, hesitation, etc.....

Seems to me that the Motorvation worked for me. Easy to install, easy to tune, and easy to modify on the fly.

Mick will tell verify, he's been giving me help for 2 years trying to get my tune right. I've been working with the stock ECU a long time. It was GOOD just wasn't GREAT! The guy who I had helping locally, I think was over his head.

The Motorvation ECU was tuned in 3 hours for a perfectly good street tune (just starting is a little hard but I only get one shot a day at that). And the car is running FAR BETTER than it was two months ago.

Faster chips, better technology, and native PC interface have made tuning MUCH easier. The stock ECU is a lot more granular, however, it is pretty complicated. The whole point of tuning is to get the amount of fuel you need into the car, to get the AFR you desire, and match it with the correct spark timing. It's not really magic, but it IS complicated. Mick is one of the smartest guys I spoke to regarding the stock ECU. The reality is, there aren't many of them around anymore. I think the MOTORVATION solution is a great solution for the novice tuner.

I understand the theory, putting it into practice on a stock ECU was REALLY time consuming and I just wanted to DRIVE the car.

Seems to me that the Motorvation worked for me. Easy to install, easy to tune, and easy to modify on the fly.

This 12% airmass error can get carried over to the idle control strategy, making it that much more difficult for the ECM to precisely control idle speed with the IAC motor or electronic throttle control system.

I'm curious. Is this the main reason that makes the idle so difficult to tune sometimes due to that 12% carried over?

I'm curious. Is this the main reason that makes the idle so difficult to tune sometimes due to that 12% carried over?

Not so much the 12% is carried over, although that is a problem, but more of not having the correct information to deal with it.

I cite this thread as a perfect example of what can happen.

http://www.smokinvette.com/corvetteforum/showthread.php?t=40614&highlight=Bosch

USUALLY we have no problems with modified injectors, but tuning can be a real PIA if you don't have the information you need, as pointed out there.

We try to develop the information listed for all of our modifications to assist in tuning.

I wanted to share this with you guys so you can see how to do some troubleshooting using a datalog program.

Here was the problem

Car started to act as if it were misfiring / skipping.

so I did a quick datalog. On this screen shows my problem.

Before I post what was wrong I figured I'd have you guys take a look and tell me what you think?

http://i60.photobucket.com/albums/h5/slvrvette/TPS.jpg

If that WB is correct, your AFR is all off.

If that WB is correct, your AFR is all off.

Nope... WB is disconnected for now. Had to send the controller out for repair.

Nope... WB is disconnected for now. Had to send the controller out for repair.

See, here's the thing... All those screens, WHY? All those parameters, WHY?

With 2 kids a boat, the car, and a house I have limited time to screw with this stuff which is why it has taken my so long to get a tune.

I have come to the conclusion that this is a great to understand HOW this stuff works in a theoretical sphere ( which is where I'd like to see this go) but in practice, the time, money, effort spent trying to tune this way, IMO is an exercise in futility with anything other than a mild build. I am NOT saying guys like MICK didn't get it to work, or CAN'T.

I am saying for the average Joe, there are better solutions if you truly want to just drive the car.

I wanted to share this with you guys so you can see how to do some troubleshooting using a datalog program.

Here was the problem

Car started to act as if it were misfiring / skipping.

so I did a quick datalog. On this screen shows my problem.

Before I post what was wrong I figured I'd have you guys take a look and tell me what you think?

http://i60.photobucket.com/albums/h5/slvrvette/TPS.jpg



So we know the problem is a misfire/skipping problem and has gotten worse.
So the first thing naturally we look into plugs,wires,distributor cap,etc.

Now look at the first few lines and what do you see?

MPH= 0
TPS= all different %'s

Remember .54 volts = the butterflies are closed?

Why is the TPS opening up and telling the ECM that it is?

TPS sensor came loose or the voltage is not set correctly. 5 min fix problem solved, 0 dollars invested

That's a little more troubleshooting than tuning......here's where I'd like to go, and I'm working up to it.

The goal of tuning is getting the right AFR that the motor likes. My car seems to like 14.0 in general.

The direction I'd like to take is to understand how the sensors relate to AFR.

For example why is there a temp sensor and a water sensor? What do changes in those sensors mean in terms of needing to be more rich, or more lean? What does the vacuum indicate? Why does 50KPA require less fuel than 60 KPA.

I'd like to go to generalities about what the inputs are telling the ECU (in general) and what the ECU has to do to compensate. AND what you have to do as a tuner to compensate for the different conditions picked up by the sensors.

That's a little more troubleshooting than tuning.

Yes it was, and was the point of the post. To understand what "we" are seeing in a datalog an why its important.
Sure we can all go out and "buy" a tune. But if we don't understand the basics of what to look for how do we know that something is wrong.
With a purchased tune that simple error we could have easily blamed on the "tuner" and in reality it would have been the "customers" error.

I've seen way to many times over the years people who have gone out and bought a tune. Gotten there chip and because they don't understand what to look for in there datalog have ruined there engine. Then naturally put the blame on the tuner. When in fact if they had understood the basics of when to know to shut the engine down and get in touch with the tuner to figure out whats going on.
So if you have purchased a chip my advice would be to understand the basics of whats going on so you can report to your tuner. Just because one tune works on another car doesn't mean it what your car wants.


There are some really good tuning books out there to help us as well. Greg Banish has written some really good books for people like us that want to understand whats going on. The can be purchased at most of the bookstores. I'll get some titles to post, but do not have them handy right now.

Yes it was, and was the point of the post. To understand what "we" are seeing in a datalog an why its important.

Cool.

Sure we can all go out and "buy" a tune. But if we don't understand the basics of what to look for how do we know that something is wrong.
With a purchased tune that simple error we could have easily blamed on the "tuner" and in reality it would have been the "customers" error.

I agree. I think you shouldn't be allowed to work on a engine without a basic understanding of how things work. You'd be surprised how simple this stuff is if you take the time to understand it.

I've seen way to many times over the years people who have gone out and bought a tune. Gotten there chip and because they don't understand what to look for in there datalog have ruined there engine.

Yep

Then naturally put the blame on the tuner. When in fact if they had understood the basics of when to know to shut the engine down and get in touch with the tuner to figure out whats going on.

Again, yep. WHen I was tuning the stock ECU I ALWAYS had a wideband on it to avoid such a problem. The stock ECU is a real PIA without an ostrich or similar device.

So if you have purchased a chip my advice would be to understand the basics of whats going on so you can report to your tuner. Just because one tune works on another car doesn't mean it what your car wants.

Right, on the other hand, is the simplicity of newer ECUs.....

There are some really good tuning books out there to help us as well. Greg Banish has written some really good books for people like us that want to understand whats going on. The can be purchased at most of the bookstores. I'll get some titles to post, but do not have them handy right now.

I'd love to get into the WHY you do what you do. To start THINKING like the ECU.

It's 60 degrees, engine temp is 190, KPA is 50, based on the VE how much gas do I need?

I can do this, it's just extremely time consuming, considering I have never written it. :D

What hasn't been mentioned is what is needed to tune stock ECM's

This device lets you adjust tune from a laptop even while you are driving
http://www.moates.net/product_info.p...roducts_id=169

You will need this adapter also
http://www.moates.net/product_info.p...products_id=32
It replaces the factory chip ( used up to '93 ) and allows the Ostrich cable to be connected to the ECM

Using a tuning software program like TunerPro RT
http://www.tunerpro.net/
http://www.tunerpro.net/features.htm
http://www.tunerpro.net/screenshots.htm

You adjust your tune using the software on your laptop and upload it to the Ostrich.That holds the tune and runs the engine .You can remove the laptop until you want to adjust tune again

You need to download the program
http://www.tunerpro.net/downloadApp.htm

and the correct definition files for the ECM in your car
http://www.tunerpro.net/downloadBinDefs.htm