MrPackstin

iTrader: (9)

Been digging since late last night and can't come up with anything exactly.

When the car is cold it will start with a little more cranking than it should, nonetheless it starts and runs fine. However, if you let it run for about two minutes then shut it off, it refuses to start (cranks just fine) for several hours/completely cooled off.

When I did a spark test with the MSD ignition (6BTM) it would spark nice through the coil and would then start perfectly. Then I would immediately shut it off again and it would no restart until I did another spark test and again, after this test, it would start again perfectly. Again, shut it off and no restart until another spark test. This cycle was infinite.

I removed the ignition and have been playing with the stock setup. It wouldn't start so I disconnected the CTS and it started. However, after this I am again back at square one.

Today I have been disconnecting the CTS and the TPS (both and individually) and I can get it to restart after only a couple minutes, which is one heck of an improvement. I set the TPS to .54 volts and 5.02 at WOT.

The only other thread I found on this was a few years ago (here at thirdgen) and it turned out to be the guys pick-up coil.

I always have spark and always have almost 50lbs of fuel pressure. Car always runs great when I can get it to start.

I would appreciate any other ideas from experts before I pull the distributor and replace the pick-up coil or stator.

GTA88

Do you have an ignition control module on top of the distributor plate, under the rotor? That fixed a similar warm-no-start condition in my 85 Chevy Caprice. $17.50 for the small electronic part, held in by one screw, snaps right out of the harness. Just a thought! Good luck .....

jermdm

60 psi of fuel pressure? Thats way too much. It should be about 44 psi at idle with the vacuum line disconnected from the regulator.

vetteoz

iTrader: (13)

have you pulled the codes to see if any faults showing?

MrPackstin

iTrader: (9)

My bad...almost 50

MrPackstin

iTrader: (9)

Haven't pulled codes, because no SES light. I will clear it tomorrow and see what sets with a paper clip. I know my unplugging various sensors has set a few artificially.

Thanks for the input everyone.

MrPackstin

iTrader: (9)

Cleared codes and got it running...let idle for 10 minutes no SES light....shut it off and nothing but code 12....

I am starting to think this is fuel related. After I checked for codes I would shut it off and try to restart it immediately and it would with just a bump to the key switch.

Another symptom is if I hold the crank for a little longer (maybe 2 seconds) it causes it to take MUCH longer for it to start back up...maybe 20 minutes. So, the best way to get it started was to bump the switch and it wouldn't start, then bump it a second time and again no start, then the third time was somehow the charm.

MrPackstin

iTrader: (9)

I found that if I prime this car it will start every time. Injectors were checked three times and all are within spec. Another way I can get it to start is if I unplug the CTS.

I removed the ICM and found bad rust on the terminals that the pickup coil go onto. Also, the red jumper wire from coil to ICM was rusty and bent. I cleaned them with a smile thinking I had it..... No luck; same problem.

IF the NOID light flashes can you be sure you are getting the correct voltage. With a meter it pulses so fast it is hard to tell if the injectors are getting the correct voltage. My meter was barely showing .22. But again, if I prime it it then runs fine.

Appreciate any feedback, to include burn it to the ground. I think I need a day off.

Big Dog Chevy

Had a problem like this with a car I was working on a while back. Try a new ignition module (a bad mod might be getting hot) and if that dosen't work try to restart it with a battery charger on the battery (it will turn over faster if the battery is weak). I had to spray a little starter fluid in it to get it started once warmed just like you before I changed those two things. The guy hasnt had a problem since.

MrPackstin

iTrader: (9)

Thanks for the ideas. I had the ICM tested 14 times (literally) today and it passed every time. I also put it on the heater before I got there to try and warm it. Changed pickup coil. Still very much the same. Maybe I will try the other car battery.

MrPackstin

iTrader: (9)

I ordered a new ICM just because it is so often the culprit under these circumstances. I only know to pray and throw $ at it now.

Changed pickup coil today...no luck.

MrPackstin

iTrader: (9)

Changed ICM today.....no luck. Car is really beginning to **** me off.

When it is warm it must have a shot of starting fluid and it starts fine. Cold it fires up immediately.

MrPackstin

iTrader: (9)

OK, I got a new fuel pump pressure tester today. The car now has 0psi of fuel pressure after it had been sitting overnight. Next, I turned the key switch to run (not crank) and it was 43psi very shortly after the pump started running. During idle it was around 38'ish. Then I turned key off and it stayed at 44. While it was warmed-up and would not start it stayed at 43 pounds.

These readings don't seem to suggest a problem do they?

Big Dog Chevy

Nope that's not it. Did you try a hot start with the charger on the car yet?

MrPackstin

iTrader: (9)

During no start period I put the charger on 50 amp...no luck.

If you have a second take a look at this: https://www.thirdgen.org/forums/tech...body-swap.html

Big Dog Chevy

If you have a second take a look at this: https://www.thirdgen.org/forums/tech...body-swap.html

Oooohhh ok, I didn't know you had a bigger TBI on it. Yeah you need to tune the computer for that TB. That's the problem right. Whenever you make changes to the air or fuel flow or requirements you need to tune the computer to the changes.

iroczjoe

o god never use starting fluid on a hot engine.

MrPackstin

iTrader: (9)

LOL...Do you have story to tell?

MrPackstin

iTrader: (9)

Yes, this is my theory. Going to put on an original throttle body and see what happens.

Big Dog Chevy

Never had one single problem doing that in 24 years. Built many engines and cars.

MrPackstin

iTrader: (9)

Still beside myself with this car.

I took the intake boot off the air filter and the MAF sensor and placed my hand over the maf causing the car to die. When I restart after doing this it starts with a bump of the key switch like a new car. For some reason the car must be running too lean, but it idles fine and does not have any codes.

I cleaned the injectors with a syringe, rubber hose and carb choke cleaner.

From the start of the thread to now it has chaned for the better very little. Now (after disconnecting the supercharger plumbing) I can get it to start a little better but it takes far more cranking than it should.

When I go to start it after it has been sitting for a while it just takes more cranking to fire than it should.

Reid Fleming

iTrader: (2)

Have you checked the ohms of the injectors? Both cold and hot? If so, what are the numbers you're getting.

MrPackstin

iTrader: (9)

I did check them all at both times. Actually, I tested them hot while the car was running...all 12.2-12.6. The injectors are actually 24lb Delphi/Rochester according to my sources.

MrPackstin

iTrader: (9)

Polished ground wires, bolts, nut and body strap to a HIGH SHINE with a dremel...no change. Throwing a set of Bosch III injectors at it now.

MrPackstin

iTrader: (9)

OK, the finale to this. The injectors that came in the car were LT1 (24lb) injectors that are 12.2 ohm. I put in a set of Bosch III 22lb injectors and it is fine.These Bosch are 14.2 ohm. FINALLY! Thanks all.

GoldenBird

I know this thread is old...but I just purchased an 89 GTA and its doing the exact same thing....but my engine is a stock (L98) 5.7 TPI. I've not done any of the clean up and test that you went through....but wondering what the thoughts are on me starting with injectors? Thanks.

ironwill

Before you start throwing parts ($$$) at the car, do some basic troubleshooting.

When the problem is present, check to see if you have:
* spark at the plugs
*Correct fuel pressure
*injector pulses at the injectors

That much should provide you with some direction from which to proceed.

A FSM is a necessity for working on 3rd gens, especially if you're new to the marque; you should be able to find one on ebay.

GoldenBird

Thank-you for the excellent feedback. In regards to FSM.... I assume your reference is to a Haynes or Chilton repair manual? If so any preferences between the two or other option?

aliceempire

iTrader: (14)

neither. Both those books are terrible for information. He really means the FACTORY service manual
here's one
https://www.factoryrepairmanuals.com...AaApdzEALw_wcB

GoldenBird

Thanks for the clarification. I found one on Ebay and ordered it.

gsmarcano

if not said before, if you run HEI, the ignition modules go bad and won't work when hot sometimes, I had it happen to me.

GoldenBird

Just wanted to update and Thank-you Ironwill for the great advice. I changed the spark plugs because they looked really bad. Turned out....the previous person installed them at .060. Changing the plugs really improved the idle.

I then checked the fuel pressure with the key in the on position. It wouldn't maintain any pressure and would fall to approximately 20 psi. I changed the fuel pressure regulator as the test primary culprit. I also changed the fuel filter because it looked as though it had never been changed. The fuel lines were so rusted....I've had to cut a foot section before and after the fuel filter.

The problem seems to be resolved. I've warmed up the car, turned it off, and restarted it numerous times with no problems. It also seems to start quicker. Again thanks for your help!

New question... there are fuel/brake line clips that hold 4 lines mounted to the body underneath. Does anyone know if these are available anywhere, what they're called, any part number? Does anyone have any tricks to how your supposed to open or remove these?