I have searched and searched.....

The car is a 1991 Camaro RS with the 305 TBI, automatic.

Will crank everytime, but, won't start.

I have done the VATS bypass. It had this problem BEFORE the VATS bypass. That is why I did it.

When it does not start, it does have a good spark BUT will not even pop, let alone run, on starter fluid.

Changed fuel filter but didn't seem to change anything. Has good pressure on prime all the way to the TB.

Drove it around last week. Starting and stopping many different places. Never had a problem. It wouldn't start the day before. Did not do anything to it. It just started the next day and ran fine.

Next day......crank, no start.
Next day......ran perfect.
Next day......crank, no start....not even with good spark and using starter fluid.

 

Are your injectors pulsing when it wont start?

 

I'll have to check with my noid light. Will post back.

But I find it strange that it will not attempt to run with starting fluid even though it has a good spark.

It started today just fine. Don't know what is going on with it. Nothing has changed and the car has not moved an inch since yesterday when it wouldn't start.

 

Hi Tater. Just because it sparks outside the engine doesn't mean the plugs are firing inside the cyclinders under pressure. I fixed and sold a truck recently that sparked great with a plug stuck in a plug wire laying on the intake. It would not fire in the cylinders at all. The rotor cap had a hole burned in it and was firing through that hole and shorting out. When the a plug wasn't under cylinder pressure it fired really nice and blue. Just that was enough to make a no start condition. I bought the truck not running and like to have pulled my hair out looking for the problem. It was a good lesson for me to go back to the most basic when facing that sort of problem. Fortunately for me I figured it out without spending big bucks like the poor guy who traded it in. Hope you find the problem.

al

 

It's all just very strange. Some days it will start and run fine. Other days it won't even start.

 

Installing a complete new distributor with ICM, plug wires and plugs in a few days.

Will post results.

I hate it when people don't post the fix.....

 

Hi hey i having a problem with my ICM going out after the first one went out i which was a GM i ordered one online oem gm and it worked only a few days and my car started shutting off and i was able to restart,sent that one back and put the new one in and it worked a few times and then my car would not start,so i purchased a another one borg warner from o reilys and now my car will not start,when i put a new icm in my car starts fine,what would cause my car to make icms to go out??? anyone know??? thanks,my car is a 87 IROC 5.7 and has some mods heads runners headers and exhaust anyone know,the car runs great when it runs

 

What fan1701 is alluding to is KV testing. As he said, you may get what appears to be a good spark with a plug laying against engine ground. That doesn't translate to the ign. system producing enough KV to support spark in a wet, cold, pressurized cylinder. The GM HEI should produce 40KV. That is equivalent to about a one inch gap in open air.

You can use a cheap adjustable KV tester available at any auto parts store, or you can place the wire end on a screwdriver tip and hold it one inch away from engine ground. You should get a bright snapping arc. If not, you may have a bad coil, or a leak to ground somewhere between the coil and the plug end of the wire. You can then test at the coil wire to see if it's the coil.

Replacing the dist. doesn't help a bad coil, unless you're talking about internal coil HEI, which the 91 TBI doesn't have.

BTW, don't really need a noid light on TBI. Just lift the air cleaner and watch, listen to the injectors.

 

Jumping in on someone else's thread isn't the best way to get help. Best to start your own thread so you get people's attention.

Sounds like you might have a coil with low primary resistance. It's overloading the ICM's coil driver. That's why you should never run a high output performance coil with a stock distributor. You can check the coil primary with an ohmmeter. It should read .6-1 ohm. If it's .5 or less, replace it. Also, make sure you install your ICM to a clean surface, after removing any dirt or old heat transfer compound. Apply dielectric grease, or the white grease that comes with the part(if it comes with it) to the metal underside of the ICM before installation. Also, makes sure your timing isn't retarded and heating up the engine bay. The ICM is very heat sensitive.

Check resistance of the pick up coil. It's the green and white wires in the little two wire connector that plugs into the inside of the ICM. It should read 800-1,200 ohms. If not, it's probably bad. Replacing it requires disassembly of the distributor. Unless you have the experience to handle this task without damaging it, it may be best to replace the distributor with a fresh reman unit. Since this appears to be a performance modified car, consider something like an MSD Probillet to replace the stock distributor. It's a better fit to your modified engine.

 

UPDATE: Seeing as every part of the car is 25 year old original, I decided to give it a tune-up just to get a baseline to work from. I swapped out the distributor for a complete new unit (cap, rotor, ignition module, etc.). Then swapped out all of the plug wires and spark plugs.

Yes.....ALL original.

It has been 3 weeks since then and the car has ZERO issues.