!984 stokck crossfire. Car died, found problem to be no spark. Verified power to coil. Replaced icm and coil. Car starts and runs great. Driving sux because I seem to have lost 1/2 the power. Kind of like driving any run of the mill chevy v8. Way more loss of power than removing HP Ign parts. Check engine light did come on and no I did not clear the codes, nor did I check them. Any ideas as to why it may loose power like that?:wtf:

!984 stokck crossfire. Car died, found problem to be no spark. Verified power to coil. Replaced icm and coil. Car starts and runs great. Driving sux because I seem to have lost 1/2 the power. Kind of like driving any run of the mill chevy v8. Way more loss of power than removing HP Ign parts. Check engine light did come on and no I did not clear the codes, nor did I check them. Any ideas as to why it may loose power like that?:wtf:

I'd start by changing the small fuel filter that is mounted on the frame right behind the right front wheel. If that doesn't solve your low power problem, check the fuel pressure at the engine. If the pressure is normal, then do a flow check on the fuel pump. It should flow around 45 gallons per hour free flow, and around 36 gallons per hour at 11 psi.

Or you can just check that the fuel pressure doesn't drop under maximum demand. You can even do that before you buy a filter.

Check engine light did come on and no I did not clear the codes, nor did I check them. Any ideas as to why it may loose power like that?:wtf:
Lose (?) power like what? High rpm? Low rpm? Missing? With a complaint as vague as "lost 1/2 the power. Kind of like driving any run of the mill chevy v8" it is hard to guess the cause. Since adding high performance ignition parts will gain you no power, the comment "Way more loss of power than removing HP Ign parts." doesn't tell us much, either. The first thing you should do is check and trouble shoot the code(s). Did you install the proper coil? Since you replaced them, I ***-u-me the coil and icm tested bad?

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I suggested changing the small fuel filter first because most '84 Corvette owners don't even know one is there. And because they don't know one is there, it is most likely plugged up for sure.

Because they're so darned small, I replaced mine with a 1 quart Caterpillar 6 micron spin on fuel filter many years ago. I have the spin on filter mounted between the spare tire and the rear frame.

Mine is in the same location as on L98 cars and close in size, also. Since it is a maintenance item, there is no harm in changing it, but I think I'd start with the known problems, like pulling the codes.

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Or you can just check that the fuel pressure doesn't drop under maximum demand. You can even do that before you buy a filter.


Lose (?) power like what? High rpm? Low rpm? Missing? With a complaint as vague as "lost 1/2 the power. Kind of like driving any run of the mill chevy v8" it is hard to guess the cause. Since adding high performance ignition parts will gain you no power, the comment "Way more loss of power than removing HP Ign parts." doesn't tell us much, either. The first thing you should do is check and trouble shoot the code(s). Did you install the proper coil? Since you replaced them, I ***-u-me the coil and icm tested bad?

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Thank you for the replies. When the car died I checked for fuel, could see injectors spraying. I checked for spark at the distributor-no spark. Found battery power to distributor. So I went to auto zone and got the 2 most likely suspects. Swaped out the icm first- still no spark. Swaped out coil-started right up. Engine runs ok, no misses no backfires. Trans is functioning properly when driving. If I could make it start out in 3rd gear that would be a great example of the power loss I feel. As far as I know there are now restrictions to the air intake however I have not put my eyeballs on the intake sys. Will check codes and make sure she is breathing and check back.

So I went to auto zone and got the 2 most likely suspects. Swaped out the icm first- still no spark. Swaped out coil-started right up.
My local Auto Zine will test parts like that for no charge. I just hate to see people wasting money throwing parts at problems, instead of taking the time to trouble shoot.


As far as I know there are now restrictions to the air intake however I have not put my eyeballs on the intake sys. Will check codes and make sure she is breathing and check back.
Has the distributor moved? Timing? Another possibility that occures to me is a plugged exhaust/cat. Pulling the codes may supply the answers.

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My local Auto Zine will test parts like that for no charge. I just hate to see people wasting money throwing parts at problems, instead of taking the time to trouble shoot.



Has the distributor moved? Timing? Another possibility that occures to me is a plugged exhaust/cat. Pulling the codes may supply the answers.

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Checked out the code, only found 1. It's a code 42. Electronic spark timing. I allready know the ignition controll module is good. Checked wiring and connectors between icm and ecm. Acording to the service manual the ecm could be bad. Am I overlooking anything. Thanks

Checked out the code, only found 1. It's a code 42. Electronic spark timing. I allready know the ignition controll module is good. Checked wiring and connectors between icm and ecm. Acording to the service manual the ecm could be bad. Am I overlooking anything. Thanks
Is the EST connector at the brake booster connected? The one you disconnect to check the base timing? What led up to the initial "Car died" problem? Was there any maintenance or repairs performed immediately preceding the problem? There are an awful lot of ECMs that get replaced, needlessly, by mistake. The fact that the coil change got it running again, leads me away from the ECM. Are you sure you used the correct replacement coil? That is all I have based in your input. Good luck.

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Is the EST connector at the brake booster connected? The one you disconnect to check the base timing? What led up to the initial "Car died" problem? Was there any maintenance or repairs performed immediately preceding the problem? There are an awful lot of ECMs that get replaced, needlessly, by mistake. The fact that the coil change got it running again, leads me away from the ECM. Are you sure you used the correct replacement coil? That is all I have based in your input. Good luck.

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Initialy the car was runing fine. Parked it and went into the store, came out and it would not start. I have not checked the est connector. I looked at it and saw it was connected but did not check for continuity. As far as the coil goes I am only trusting that the parts guy gave me the correct part. Is there a way to tell? Do you know of any websites where I can look up part numbers for this car to get original #'s, what they may supercede to and crossreference to other parts manufacturers? Hopefully I'll be able to check out the est connector today. Will check back. Thanks.

Update: CFI-EFI I checked the EST connector. Found the reason it was taped together and made repair. Check engine light is out and engine is runing strong. Thank you for your help.

Update: CFI-EFI I checked the EST connector. Found the reason it was taped together and made repair. Check engine light is out and engine is runing strong. Thank you for your help.
I'm glad you didn't end up having to spend any more money on it. Too many times people forget to reconnect the EST wire after adjusting the timing and the result is a code "42" until reconnected and the code cleared.

The Corvette HEI coils are a reverse polarity from many other applications. The tip off is the primary lead colors. One has red and white and the other has red and yellow. The incorrect coil will work and the car will run, but the coil output is reduced and might cause it to run like "it start out in 3rd gear". I'm sorry to ask so many questions, but maybe it is more clear now, why. I'm glad we saved you from buying an ECM.:thumbsup:

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I'm glad you didn't end up having to spend any more money on it. Too many times people forget to reconnect the EST wire after adjusting the timing and the result is a code "42" until reconnected and the code cleared.

The Corvette HEI coils are a reverse polarity from many other applications. The tip off is the primary lead colors. One has red and white and the other has red and yellow. The incorrect coil will work and the car will run, but the coil output is reduced and might cause it to run like "it start out in 3rd gear". I'm sorry to ask so many questions, but maybe it is more clear now, why. I'm glad we saved you from buying an ECM.:thumbsup:

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As pertaining to the coil,I did notice a difference in the wireing on the new coil, the colours are different like you sugested (in other words I have the wrong one). The car runs and drives great city\highway. The problem I am having now is that when I get on it, it will spin the wheels out of the hole, spin second and then fall flat on it's face. Does not break up, no backfireing, no pops through the intake. I let up and it recovers and drives fine. Did not have this problem before the ignition prob. Question is, will the wrong coil cause this problem?

The problem I am having now is that when I get on it, it will spin the wheels out of the hole, spin second and then fall flat on it's face. Does not break up, no backfireing, no pops through the intake. I let up and it recovers and drives fine. Did not have this problem before the ignition prob. Question is, will the wrong coil cause this problem?
Possibly, but I wouldn't expect the problems of the wrong coil to be so abrupt or dramatic. Like the check engine light, take care of the obvious, first. Make sure of your coil. If the wires are different colors, one of them is wrong. If they sold you the wrong coil, make them replace it with the correct one.

The problem you describe sound more like fuel, to me. I would connect a fuel pressure gauge and observe the pressure as the problem occurs. How ling since the fuel filter was replaced?

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Possibly, but I wouldn't expect the problems of the wrong coil to be so abrupt or dramatic. Like the check engine light, take care of the obvious, first. Make sure of your coil. If the wires are different colors, one of them is wrong. If they sold you the wrong coil, make them replace it with the correct one.

The problem you describe sound more like fuel, to me. I would connect a fuel pressure gauge and observe the pressure as the problem occurs. How ling since the fuel filter was replaced?

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I'm sorry it took so long to get back on this. It's been raining almost non-stop here in southern NJ. I was able to check the car out today. No new codes found. Checked fuel pressure, Found a drop under a load, r&r fuel filter, solved the problem. Thank you very much for your help.

Checked fuel pressure, Found a drop under a load, r&r fuel filter, solved the problem. Thank you very much for your help.
Cool!!! Thanks for the feed back. I'm happy if any of my advice was helpful

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