93 corvette issue with staying running

[kwik1979]

just startd doin this wher the car runs forbout 30 min then shuts of .it losing the injector pulse .i put noide light on it ..if i wait 30 or more mintutes the car fires up like theres no problems revs fine but then it runs and keeps doin same thing ..any body ever have this problem. no check engine light im thinkn distrbotor 145000 miles but car dont ack like it that ingition seems stronge fires up really good when it does run

 

[gmjunkie]

just startd doin this wher the car runs forbout 30 min then shuts of .it losing the injector pulse .i put noide light on it ..if i wait 30 or more mintutes the car fires up like theres no problems revs fine but then it runs and keeps doin same thing ..any body ever have this problem. no check engine light im thinkn distrbotor 145000 miles but car dont ack like it that ingition seems stronge fires up really good when it does run

Yeah,Everybody blaims the Opti-spark first thing!~!!

I've worked on hundreds of LT1 and LT4 cars doing the same thing,and I've only had to replace 4 Opti-sparks in my entire professional wrenching career.:L
1 from a Wreck.
2 just went bad.
1 replaced because the new one was faulty.

Several other things can cause the same symptoms,High resistance Grounds heating up,Coils,Ignition Modules,ECM's,TPS's and even fuse connections heating up and loosing continuity!


Your best bet is to get a 93 FSM and go through the check lists!
Your problems require more than a good guess!

 

[John Robinson]

As Junk says it could be a lot of things. Having had something similiar with my 93 I would suggest you start with the TPS. Mine went bad and did not set a code. It was sending a signal to the ECM that it was flooded and the ecm is programmed to shut down the pulse until the cylindeers clear out. From there I had to clean all the grounds and even repair broken wires from the TPS and MAF and the temperature sensor on the water pump. Again as Junk said there are more things than you can imagine that can cause these problems and nothing will work until you get the FSM and systimatically go through each diagnostic chart. If Junk tells you something take it to the bank he probably has more knowledge about these cars then the engineers who designed them.


Welcome to The CAC

 

[boomdriver]

fuel filter. pressure test.
The noid may not indicate inj pulse unless the ecm gets a permission thru the engine actually firing and turning over on its own. No fuel...no fire, no inj pulse.

 

[kwik1979]

As Junk says it could be a lot of things. Having had something similiar with my 93 I would suggest you start with the TPS. Mine went bad and did not set a code. It was sending a signal to the ECM that it was flooded and the ecm is programmed to shut down the pulse until the cylindeers clear out. From there I had to clean all the grounds and even repair broken wires from the TPS and MAF and the temperature sensor on the water pump. Again as Junk said there are more things than you can imagine that can cause these problems and nothing will work until you get the FSM and systimatically go through each diagnostic chart. If Junk tells you something take it to the bank he probably has more knowledge about these cars then the engineers who designed them.


Welcome to The CAC

i check tps sensor with my scanner workn good no clear flood i got my five volt rev to

 

[kwik1979]

fuel filter. pressure test.
The noid may not indicate inj pulse unless the ecm gets a permission thru the engine actually firing and turning over on its own. No fuel...no fire, no inj pulse.

i hav good fuel pressure and good spark car runs great but just keeps losin injet pulse check the tps

 

[LLC5]

just startd doin this wher the car runs forbout 30 min then shuts of .it losing the injector pulse .i put noide light on it ..if i wait 30 or more mintutes the car fires up like theres no problems revs fine but then it runs and keeps doin same thing ..any body ever have this problem. no check engine light im thinkn distrbotor 145000 miles but car dont ack like it that ingition seems stronge fires up really good when it does run

You can still have codes in the ECU without the check engine light being on, I would see if there are any that could be related to your problem. Good luck with it.

 

[kwik1979]

You can still have codes in the ECU without the check engine light being on, I would see if there are any that could be related to your problem. Good luck with it.

hav no codes ive checkd with scanner car is losing injector pulse after it runs for a while and will start back up if i wait bout 30 mins each time it does it

 

[John Robinson]

The ignition coil requires a silicon grease between it and the block. According to the FSM this is for cooling purposes. You might try removing the coil and regreasing it with fresh silicon grease that is designed for this application. A word of caution on all the wire connectors the wires are very thin and are quite old. Use care in how you handle them because they will break internally and then you will have to rewire them. Been there done that have the t shirt. Realistically you need to get the FSM if you plan to keep this car for awhile. If you have never worked on a car with this type ignition particularly one with a plastic body you will have to unlearn eveything you know and start over.

 

[LLC5]

hav no codes ive checkd with scanner car is losing injector pulse after it runs for a while and will start back up if i wait bout 30 mins each time it does it

Do you have a good blue spark at the plugs when the vehicle will not run, and at the same time there is no injector pulse?

 

[kwik1979]

Do you have a good blue spark at the plugs when the vehicle will not run, and at the same time there is no injector pulse?

im lose all spark when i have no injector pulse.. i hav nothin out of coil i hav power to distbtor and ground.icheck hav power to coil and through coil and icm both hots there..

 

[kwik1979]

im lose all spark when i have no injector pulse.. i hav nothin out of coil i hav power to distbtor and ground.icheck hav power to coil and through coil and icm both hots there..

i hav mitchell on demand that i use..

 

[LLC5]

i hav mitchell on demand that i use..

When the problem is active, do you have battery voltage at the injector wire harness connector with ignition on AND during cranking?

 

[kwik1979]

When the problem is active, do you have battery voltage at the injector wire harness connector with ignition on AND during cranking?

yes hav power the car did it twice this morning actd up but somtimes like now the car has been runin four 4 hours with out problem

 

[LLC5]

yes hav power the car did it twice this morning actd up but somtimes like now the car has been runin four 4 hours with out problem

With ignition power at the injectors during ignition on and when cranking and no spark at the plugs, then you are probably looking at the primary side of the ignition system or a related harness issue between the distributer and ECU.

 

[DMarusa]

Same Issue

Get a cup of coffee - this is long:

Over Christmas, just as a preventative measure, I replaced the Optispark distributor. At the same time, I replaced the water pump, O2 sensors, coil and a few other sensors. I also upgrade the injectors to Bosh IIIs. Everything was fine for about two weeks and then this started happening.

Since I haven’t been able to get the engine to die in the driveway, it has been an ordeal to troubleshoot. The first thing that I did was to replace the Ignition Control Module. When you install an ICM in a HEI car, it has to be embedded in a thermal compound to the heat sink. Most auto parts stores will tell you to use dielectric grease for this, but it is non-electrically-conductive and has no thermal conductive properties. I remembered that when I changed out the coil, I washed the mounting bracket that is attached to (which also has the ICM and heat sink attached to) in my parts washer. I pulled it back off and found that the solvent had gotten behind the ICM and washed away the thermal compound, so I assumed that the ICM had gotten heat soaked since it was no longer seated properly to the sink. Usually when this happens, the heat is enough to damage the solid state components. An ICM uses crankshaft position, camshaft position or both to determine engine speed to know when to energize the coil(s). After replacing the ICM the problem continued.

When I got home, I peeled back the harness and found that the tach filter was poorly spliced in and the ground wire to it was broken. I’ve found lots of threads online that indicated that the tach signal to the PCM could cause the computer to think the wheels were spinning at a revolution not likely with the engine speed. It would send inaccurate data to the ASR system and retard the spark and ultimately kill the engine. So, I spliced the wires back with a solder joint and fixed the broken ground. The car drove fine for two days and then it died again only a block from the house. This time, it wouldn’t restart for several hours.

So, I know now that the tach filter was just a coincidence. When it is driving, the tach behaves correctly. Two weeks ago, I ordered a remanufactured ECM (engine control module) from Cardone. It hasn’t come in yet, so in the meantime I’m trying other things.

This weekend, I took both old and new ICMs and coils to Autozone to be tested. Both ICMs tested okay, but I can’t rule them out because the problem is not a complete, but intermittent failure and a few test cycles cannot isolate that. They could only test the coil with a multimeter and that does me no good because it does not stress the unit. So, I did the next best thing. I returned the new coil for an exchange. So, I know I have a good “old” coil, and I have a likely good “new” coil, so the coil is ruled out.

With the new coil, I’ve driven the car for almost 10 hours without the failure. A new set of '93 FSMs came in the mail yesterday. I hope that I’m not jinxing myself for mentioning it. Hope this helps.

 

[kwik1979]

cars fixd changed waterpump that was leakn at weap hole and distributor fixd thanks

 

[Schrade]

Good job!

Any pics of diagnostics, or work as you went along?

Pics are good. You learn stuff better about the system you're working on, others learn from your stuff here on the boards, and when you unload the car, you tell the buyer, "This is new, that is new, etc., etc.". Ever hear all about all the 'new stuff', when you're buying a car???

"Sounds GREAT there Mr. Seller; SHOW ME " (like receipts, for example). And you whip out your photo-documented work on the boards, lots of snappics yUP!!! And your price goes up, since you have PROOF of work uH-HUh yuP.