?? regarding 1992 corvette

FED 387 · 08-11-2016, 10:24 PM

My son has a 1992 Corvette--- just an everyday car NO MODS!!! lately the engine has decided to run rough then smooth out and sometimes even quit--let it set a few minutes starts right up and drive it away engine running smooth--- let it idle in the driveway might run for 10-20 minutes then act up then run smooth out then all of a sudden die--we have checked the obvious plugs-wires--coils--fuel filter-ECM---put it on a Code Reader threw a voltage code once checked that out Alternator was bad voltage all over the place replaced it--replaced the Opti spark unit the whole thing cap rotor even the distributor---cannot find anything that will do this--- he's having fits over this I know nothing about these computer cars--could the computer be bad ??? Anybody got any ideas??? He has a Camaro same engine absolutely NO problems with it so far-- I'm out of suggestions THnax guys FED 387

ss3011 · 08-11-2016, 10:43 PM

Just an idea . Can you install a fuel pressure gauge on the fuel rail and monitor the pressure when it has it's problem ?

Woodfin · 08-12-2016, 04:51 AM

Suggestions, look closely at the secondary wire between coil and distributor. Look at coil terminal for corrosion or carbon tracking.

Swap the ecu relay with the relay from another component that uses the same relay.

Another possibility is the primary connector at the ignition coil. It is a known issue for the primary connector to break internally. A replacement "pigtail" is available.

Bob Don · 08-12-2016, 07:49 AM

Check all your sensors. I had a mid '80s vette with a bad temperature sensor. It kept telling the computer the engine was cold and the computer would send too much fuel, causing similar symptoms as you described.

FED 387 · 08-12-2016, 08:08 AM

thanx for the answers we will check them out get back to all with our results--FED 387

Woodfin · 08-12-2016, 10:01 AM

another thought, use a fully capable scan tool that will show all live data, pending codes and history codes

cad · 08-12-2016, 10:04 AM

Quote:

Originally Posted by Bob Don

Check all your sensors. I had a mid '80s vette with a bad temperature sensor. It kept telling the computer the engine was cold and the computer would send too much fuel, causing similar symptoms as you described.

I second this. My father in law has replaced more temp sensors than he can remember. Cheap and affects how it idles/runs/mileage, etc.

Ed Wright · 08-12-2016, 01:58 PM

The high tension coil wire is a common problem with the LT1 cars. I used to keep one on the shelf when I had my shop open. Check the coolant temp on your scan tool. An open in the sensor, or connector indicates -40 deg. That should be black smoke on start up. Same as the choke shut tight on a carb.

merrill 2733 · 08-12-2016, 09:29 PM

You might want to check the fuel injectors, that era was bad about heat on them. Original injecters had issues, cold run & start perfect till you get underhood temp. To them, hope it helps.......good luck!!!!!!!

08-11-2016, 10:24 PM	#1
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,349 Likes: 327 Liked 280 Times in 150 Posts	?? regarding 1992 corvette My son has a 1992 Corvette--- just an everyday car NO MODS!!! lately the engine has decided to run rough then smooth out and sometimes even quit--let it set a few minutes starts right up and drive it away engine running smooth--- let it idle in the driveway might run for 10-20 minutes then act up then run smooth out then all of a sudden die--we have checked the obvious plugs-wires--coils--fuel filter-ECM---put it on a Code Reader threw a voltage code once checked that out Alternator was bad voltage all over the place replaced it--replaced the Opti spark unit the whole thing cap rotor even the distributor---cannot find anything that will do this--- he's having fits over this I know nothing about these computer cars--could the computer be bad ??? Anybody got any ideas??? He has a Camaro same engine absolutely NO problems with it so far-- I'm out of suggestions THnax guys FED 387

08-11-2016, 10:43 PM	#2
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: ?? regarding 1992 corvette Just an idea . Can you install a fuel pressure gauge on the fuel rail and monitor the pressure when it has it's problem ?

08-12-2016, 04:51 AM	#3
Woodfin Member Join Date: Sep 2006 Location: Kilgore TX Posts: 428 Likes: 5 Liked 70 Times in 38 Posts	Re: ?? regarding 1992 corvette Suggestions, look closely at the secondary wire between coil and distributor. Look at coil terminal for corrosion or carbon tracking. Swap the ecu relay with the relay from another component that uses the same relay. Another possibility is the primary connector at the ignition coil. It is a known issue for the primary connector to break internally. A replacement "pigtail" is available.

08-12-2016, 07:49 AM	#4
Bob Don VIP Member Join Date: Oct 2002 Location: Greater Boston Posts: 1,476 Likes: 980 Liked 778 Times in 175 Posts	Re: ?? regarding 1992 corvette Check all your sensors. I had a mid '80s vette with a bad temperature sensor. It kept telling the computer the engine was cold and the computer would send too much fuel, causing similar symptoms as you described. __________________ Bob Don 128 SS

08-12-2016, 08:08 AM	#5
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,349 Likes: 327 Liked 280 Times in 150 Posts	Re: ?? regarding 1992 corvette thanx for the answers we will check them out get back to all with our results--FED 387

08-12-2016, 10:01 AM	#6
Woodfin Member Join Date: Sep 2006 Location: Kilgore TX Posts: 428 Likes: 5 Liked 70 Times in 38 Posts	Re: ?? regarding 1992 corvette another thought, use a fully capable scan tool that will show all live data, pending codes and history codes

08-12-2016, 01:58 PM	#8
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 389 Times in 168 Posts	Re: ?? regarding 1992 corvette The high tension coil wire is a common problem with the LT1 cars. I used to keep one on the shelf when I had my shop open. Check the coolant temp on your scan tool. An open in the sensor, or connector indicates -40 deg. That should be black smoke on start up. Same as the choke shut tight on a carb. __________________ Ed Wright 4156 SS/JA

08-12-2016, 09:29 PM	#9
merrill 2733 Junior Member Join Date: Dec 2010 Posts: 41 Likes: 0 Liked 7 Times in 6 Posts	Re: ?? regarding 1992 corvette You might want to check the fuel injectors, that era was bad about heat on them. Original injecters had issues, cold run & start perfect till you get underhood temp. To them, hope it helps.......good luck!!!!!!!