[toobroketoretire]

I have had an unusual problem ever since I installed my Edelbrock and #3310-2 Holley. After one month of light-throttle cruising I get an ENORMOUS loss of power for 5-6 seconds when I open my secondaries. I have a gut feeling the fuel in the secondary bowl is "going bad" and is the reason for the enormous loss of power. Once I have experienced that 5-6 second loss of power all things return to normal and stay that way for at least a week.

So my question is this: At what point does our fuel go "bad"? The fuel stored in a non-vented tank is kept pretty cool and mixed with a lot of other fuel but the 3 ounces of fuel in a vented secondary bowl is stored in a real hot 200-250 degree environment. So at what point can that 3 ounces of fuel go "bad" enough to the point in which it won't ignite under high cylinder pressures?

I recently installed a 1/8" copper line joining my secondary bowl to the suction line and the problem hasn't surfaced since. So I'm wondering if "bad" fuel was causing it.

Any thoughts?

 

[Slicktop]

Did you ever stop to think that since you are the only one in history to experience this that YOUR carb is screwed up.........gas does not go bad in the short time span that you are talking about, period..........

 

[toobroketoretire]

Did you ever stop to think that since you are the only one in history to experience this that YOUR carb is screwed up.........gas does not go bad in the short time span that you are talking about, period..........

Slick, if you'll reread my post I asked the question "at what point does fuel go bad in which it won't light off under high cylinder pressures".

 

[Slicktop]

Slick, if you'll reread my post I asked the question "at what point does fuel go bad in which it won't light off under high cylinder pressures".

Like I stated in your previous thread cars in storage for 6-12 months start and run fine and those engines also have "high cylinder pressures".

Also, if you buy gas at a rural station that gas could have been in the stations storage tank for a long time.........

Contact the experts, your favorite gas company, when they mix their fuels they do extensive testing and might have further insight into your "problem".

 

[toobroketoretire]

Like I stated in your previous thread cars in storage for 6-12 months start and run fine and those engines also have "high cylinder pressures".

3 ounces of fuel stored in a vented bowl and at temperatures of up to 250 degrees is a lot different than 15-20 gallons of fuel stored in a un-vented gas tank at ambient temperatures.

 

[toobroketoretire]

Also, if you buy gas at a rural station that gas could have been in the stations storage tank for a long time.........

My local gas station is a Vallero that has 10 pumps and gets a load of fuel most every day.

The first time it did it I assumed my plugs had gotten fouled from all the low speed low rpm driving I do so Fish sent a pair of #70 jets to me so I could lean it down about 5%. But after another month of low speed low rpm driving it did it again. And each time the whole "event" lasts about 5-6 seconds. Once the event happens it'll run perfectly for at least a week when it begins to exhibit the same symptoms but not nearly as bad. Feels just like a 5-6 second loss of fuel pressure. And when it does it I can't feel any missing....................just an enormous loss of power.

 

[[email protected]]

Did you ever stop to think that since you are the only one in history to experience this that YOUR carb is screwed up.........gas does not go bad in the short time span that you are talking about, period..........

if it is a carb malfunction, why does it only do it once, then operate perfectly fine afterwards? and then wait a month before doing it again and only if you don t use the secondaries during that month? ...that is the mystery.. I took the problem directly to Holley.. they cannot explain it either.

 

[toobroketoretire]

if it is a carb malfunction, why does it only do it once, then operate perfectly fine afterwards? and then wait a month before doing it again and only if you don t use the secondaries during that month? ...that is the mystery.. I took the problem directly to Holley.. they cannot explain it either.

I have a feeling it's just fouling on the plugs and it takes 5-6 seconds to burn it off. Because I recall my '82 doing the exact same thing after extended low speed driving.

 

[Slicktop]

Well, then we are back to a discussion about plugs. In 1965 I bought an Austin Healey 3000 and it continuousy fouled American plugs. Parts guy suggested trying NGKs, saying that they would not foul easily and if fouled would clean up under acceleration. Guess what, he was right and I have been using NGK plugs ever since with never a fouled one in all types of cars. We are talking about regular NGKs, not platinums, etc. The regular NGKs have a wide flashpoint and a copper core and just do the job. Try a set.

 

[[email protected]]

maybe you just need to go one heat range hotter , since you mostly drive low rpm anyway

 

[Slicktop]

Good point, he has a newer overdrive type tranny in that car and that engine is not designed to lug at the rpms he is running at cruise. He has stated that he is running 1800rpm at 70mph when originally that engine was probably running 3000rpm at 70mph with the original tranny. Trannys need to be matched to an engines torque curve otherwise lugging can occure. That could very well be the problem. He is driving arround at rpms much lower than the engine was
designed to operate at , lugging it, and the engine is fouling up as a result.Then when he gooses it it falls on its face because it is loaded up........

I wonder about going to a hotter plug though. I always worry about damaging an engine doing that. Think he should try the NGKs first in the proper heat range.

 

[lostvette]

Bad

E 3"S :doh:

 

[toobroketoretire]

I'm running AC45XLS (3/4" reach gasket-type) and they're as hot as I would ever want to go as they always come out white.

But after further thinking about this I clearly remember my '82 doing the same thing after extensive low rpm driving. It too would fall flat on it's face for about 5-6 seconds as the deposits got burned off then run great for a long time afterword.

As a spark will always take the easiest path to ground it doesn't take very much fouling (or deposits) to create a path to ground and cause misfiring. And at a rpm of 3000 or more the speed alone could easily mask the intermittent misfiring of 8 cylinders.

And......................NGK's are not one bit better than AC Delcos.

 

[toobroketoretire]

By the way, I'm running a 220/220 .500" lift marine cam that develops the torque at a pretty low rpm and I'm also running it 4 degrees advanced to enhance low end torque. My driving habits are usually running at around 55 mph at around 1450-1500 rpm. About twice a year I'll reach speeds as high as 70 mph when I go to the coast (175 miles away) for a day and by the time I get there I can tell a definite difference in how much better it runs.

And then there's something else that no doubt compounds the problem. My Edelbrock RPM Air Gap intake manifold as it's 2" taller than stock, has a very large plenum, and it's runners are considerably larger in cross section.....................which slows down the velocity and adds to fuel separation. So the fuel mixture at low rpm's is probably pretty sloppy.

Probably just minor fouling on the plugs and it just feels like it's stagnate fuel because of the 5-6 second delay. I'll know more as I continue to drive it. At least with the copper tubing installed I'll always have fresh fuel in the secondary bowl.

 

[toobroketoretire]

Remember guys, I never said the fuel is going bad. I just said I was suspecting it was going bad because of the odd 5-6 second delay.

Now I'm suspecting the plugs are getting fuel fouled because of the Edelbrock and TH700R4.

The plugs are the "extended reach" style and I might be better off running standard plugs (if they make them) to better shield the electrode.

 

[Slicktop]

Do not be stubborn, try the NGKs. Until you actually try them you have no experience with them to make a judgement. AC plugs always gave me problems before I switched to NGKs.

 

[toobroketoretire]

AC plugs always gave me problems before I switched to NGKs.

And what kind of "problems" did you experience? I have used them all my life and never had any problems. And the other 10 million G.M owners haven't had any problems either.

 

[toobroketoretire]

Well, it did it again but for only 2 seconds this time. I went to the corner store and on the way back I had to give it a HEAVY throttle in 3rd gear at about 40 mph because of an approaching car.

It fell flat on it's face for 2 seconds then made full power. So now I'm even more convinced it's fouled plugs because of my constant low rpm/low load driving.

I'm going to pull the plugs tomorrow morning and sandblast them. I'll let you guys know what I find and I'll also take a picture or two.

 

[Slicktop]

And what kind of "problems" did you experience? I have used them all my life and never had any problems. And the other 10 million G.M owners haven't had any problems either.

Loading up and misfiring/not firing in British sportscars. Also, my 85 vette started idling rough and when I pulled the plugs, guess what, they were ACs. Put NGKs in and idles and runs great......Just try a set, they are only $2 each.
Think that your real problem is that your engine is lugging and loading up because you are constantly running it below its torque power band, but changing to a different plug like NGK is worth a shot. Remember your 82 doing the same thing with ACs? Well my 85 has a 2.59 rear end and it also runs 1800rpm at 70mph and never loads up using NGK plugs........when I floor it, it screams.....Of course the l98 is a high torque low rpm engine by design.

 

[toobroketoretire]

Just try a set, they are only $2 each.

Not interested,,,,,,,,,,,,,,,,,,,,