ZZ4TPI 92MAP system. Car doesn't want to restart after it gets hot. Cranks but no start.
Base timing is set at 8* adv. If I physically move the distributor and advance the timing, the car will restart.

The following things have been replaced fpr swapped to rule them out:
New Computer ECM/New Ignition module,Cap,rotor/ New IAC.
I swapped a different coil and unplugged my MSD and tested. Spark and fuel do not seem to be the problem.

Is there something inside a small style, stock HEI distributor that moves to advance timing?

Could something be freezing up inside my distributor when hot, and not allowing timing to advance to start the car?



------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

have you actually found that you dont have
spark?
fuel pressure is?
injector pulse?
voltage drop between ingition system and
battery?
92 speed density systems are 100% non mechanical
timing...
mechanical timing was done away with in 81
with the introdution of C3 computers..
try those checks.. becasue youve changed parts
doesnt rule out those systems...
sorry...
airdeano

 

Fuel pressure gauge says pressure is okay, staying up around 35-42 during cranking.

I'll have my Autoxray this afternoon.

I took the car to the dealership for this problem a week ago. While cranking in the no-start condition the computer RPM went to 9999rpm. I used to be able to jumper A and B to get the car to start. Or by clearing the computer for a few minutes. So when I cleared the computer the car would start. Thats why I replaced the ECM at first, everything pointed towards it being the problem. The car seemed fine for a week but started to do the same crap again.

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Base timing is still set using the distributor. It is not all electronic.

 

Yes, I know base timing is set by unplugging the tan/black stripe wire. I built this car myself.
The Autoxray will not read the S&P ZZ4 chip, as the Datamaster software would not read the S&P ZZ4 chip but the GM Tech 1 scanner would read the chip. I'm confused.

I called S&P, they said check for a bad ground to the computer and I'll give it a go. I've had a bad ground before they can be tricky. No reason for two scanners not reading thier chip.



------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Basically the problem is this. With timing set to 10 deg adv base, the car starts and runs fine. However, after a short trip, and warming up the car will not restart. If I physically advance the distributor, the car starts.
What is heating up, causing this problem? I replaced the ignition module, swapped coils, unplugged the MSD, checked the computer ground, fuel pressure is good.

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

how about your timing chain? Do you think that maybe your timing chain is worn and is screwing up the timing? Maybe the heat/operation of the engine causes the timing chain to stretch and jump a tooth?

I'm not an expert.. just trying to help out another 3rd genner.

 

Age, the engine only has about 30K so I think the timing chain is safe.
HOWEVER, on a whim, I pulled the new Wells ignition module and took it and had it checked. BAD! So I put a good spare GM module in and will see tomorrow how she does. I think my initial problem was the computer, as I could jumper the A and B to get it too start. With the ignition module cooked, I had to bump the base timing way high to compensate.

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!