Ok here is the low down-

New 383 with VATS TPI ran for 300-400 miles w/o a problem in current configuration.. stalled with sputtering and restart/stall- then finally cranks with no start. Still has 305 EEPROM and 305 Injectors,. new 350 knock sensor (orginal with 191,000 miles on them- although I cleaned the injectors while they were out of the car)

Although every once in a while the car WILL start and sputter out to a stall when the throttle is touched.. sometimes it restarts but does the same thing...

Ck'ed fuses-ok (incl ECM, INJ 1 and INJ 2)

Ck-ed fuel pressure 39 43-ish
Since I have Fuel pressure and a new fuel pump relay we know thats good

Spark was weak with inline spark tester- (dim) replace org. coil and distributor (reman with new module too) However, since I have spark at the coil and out of the cap I know that both primary and secondary sides are functioning along with the ESC Module

No injector Pulse with TPI Noid light in #1 cyl. Althought twice during crank diagnositics with the noid light I got a pulse or two then nothing.


I only have a Haynes wirining schematic so here is goes:


Injector driver circuit grounds bank 1 and bank 2 injectors. Power comes from the I/P Fuse block via:

INJ 1 10Amp= Bat voltage with key on, 9.8-10V crank-ok

INJ 2 10Amp= same as above-ok

ECM 10A=Bat Volt.-ok

Gauge 10A= bat voltage Ok Albeit my Tachometer is still (when cranking) out of wack. It was way out of wack with the engine running before.

The Z28 is in the street so I lost daylight before I could check for power at the injectors with my DVOM and continutiny from the power lead of the inectors to the INJ1/2 fuses.

I am thinking seeing as this seems to be a common issue with my searches of the following possibilities

1) stuck injector(s) shorting the driver circuit?

2) Failed EEPROM and/or PCM?

3) short or open on the ground side of the injector harnesses on Bank 1/2 seeing as INJ 1/2 fuses are ok?

What do you all think? ANY help or pointers would be appriciated...

P.S. Are EEPROM/PCM Failures common?- When I last owned a 3rd gen its was an 88 IROC in 1995 so they weren't that old my last go around with them I never ran in to a similar problem.

 

Bump

 

Was the engine hot or cold when it stalled?

You [I]really[I] need to upgrade those injectors and get your ecm programmed. Just for starters your engine volume is way too small in the programming and so are your injectors.

You're taking the chance at melting a piston or two with any kind of pressure on the fun pedal.

 

Yea I know the injectors and the eeprom were the next upgrade on the schedule.

The car was hot... just drove it home from work, went to dinner, 1/2 way home it stalled. Acted just like running out of fuel.


Does anyone have the pin outs for a PCM connectors for a 1991 TPI?

Also I am assuming the if I need to go boneyard hopping I need to find a 1990-91-92 TPI for the computer to be the same correct?

 

Speed density 90-92 will work for you. You still run into the same injector and engine volume issue. It'll just be closer.

Ohm out your injectors to see if they're going bad.

 

10 ohms or less shows a faulty injector----

or infinite shows shorted open and faulty right?

 

I found the pinouts on the web. the pinouts are:

for Bank 1 (odd cylinders) is C11 on the PCM

Bank2 is C12 (even cylinders)

However, the signal specification on te web doesn't make sense to me.. or it might be a little too late for me.

The signal spec. key is 12V both banks, Engine running the spec is 13.9V (alternator output voltage)

Is this right?

 

If it turns out to be a PCM found a reman units for 50 bucks,, EEPROM is a differet story....

Figure I will go with a JET chip.. got 20% off them everyone else is 300+ bucks... can't find anyone local to burn/tune proms