Alex Edmonds

I have a 91 z28 camaro, 305 tpi with 104 miles on the engine. New starter, distributor, coil pack, fuel pump, fuel sending unit, fuel filter, fuel screen, fuel pressure regulator, fuel pressure regulator diaphragm, oil pressure switch, oil pump, and just about every single sensor is brand new. all the injectors ohm out at 16. it will run on fuel sprayed into the intake. there is pulse to the injectors and the fuel pressure is perfect. all the voltage lines up with factory spec. any ideas?????? what am i missing???? we have fuel, air, spark, and oil...what am i missing?

Tuned Performance

iTrader: (92)

What’s the fuel pressure at ?
Does it stay running with your foot on the throttle ?
Are the injectors stock multecs ?
Where you able to set timing with the est disconnected?

Alex Edmonds

the fuel pressure is holding quite well at the factory spec. as for the throttle, if i even give it any throttle movement it will instantly kill the engine. The fuel injectors are yes all factory to my knowledge. The timing was set with the est disconnected but i have not tried to unhook since timed and it last ran. The car drove to where it currently sits in the garage so it was in time at the time being. The car was not giving a hard time starting either. Ran smooth as silk then the next day this happen

Tuned Performance

iTrader: (92)

Have you tried to use propane or starting fluid to richer the mixture to see if it stays running longer.
Sounds fuel related injectors or a bad ecm. You have covered all other possibilities.

Alex Edmonds

i was hoping to cover the biggest known problems these cars are famous for. I planed to save the ECM for last if i could unless it is a bad ECM and POM. You are right with that one of the injectors could be faulty or they could be clogged. i did spray gasoline into the throttle body that i transferred out of the tank to make sure it was not stale and it ran just fine till the supply ran out. The only other possibilities i can think of is a bad ignition module, ignition tumbler or faulty vats not registering its bad

Tuned Performance

iTrader: (92)

The fact in runs even for a second sounds like the vats is working unless it’s a leaky injector causing it to run. A noid light would be a helpful tool for you to use.

Alex Edmonds

a noid light was used, and has confirmed pulsation in the injectors. we replaced the distributor because the pickup that caused the pulse went bad. has been checked after installation and was shown to be working. we pulled the spark plugs and got a welders blue spark. using 8mm racing performance plug wires and iridium spark plugs.

Tuned Performance

iTrader: (92)

If you want to try a ecm he’s not priced to bad.
You need a 1227730 service number ecm.
https://www.thirdgen.org/forums/engi...ls1-brake.html

Alex Edmonds

At this point there is not much left that it could be as i said earlier i was testing every single thing i could think of. i know its not exhaust back pressure because its a free flow exhaust setup(also new) what is left in the system i might not have considered ? i will ask him about the ecm tomorrow when my check clears, i hate to make people wait for payment when interested in something

Tuned Performance

iTrader: (92)

The one marked awfu comes with a memcal. It’s for a 90-92 tpi 305 automatic transmission.

Alex Edmonds

alright, thats what i have. i will send him a pm about it

BovineZro

iTrader: (11)

Hey, thanks for the referral! Glad to see one of these ECMs getting some use.

bjankuski

Make sure you have power to the computer, use a wiring diagram and then check all the power and ground connections on the computer.

Alex Edmonds

i have checked but it never hurts to double check

Tuned Performance

iTrader: (92)

If the check engine light is on before you try starting the engine the ecm is powered up. The fuse for the ecm/fuel pump is next to the battery but I doubt this is the problem .

Alex Edmonds

The check engine light is on before cranking and does not throw any codes when checked.

TT 68

This sounds like the symptoms of a bad vacuum leak causing un-metered air entering the engine to cause chaos with the tune. Maybe a gasket, connector or hose on the intake failed or one of the runners is not sealed well at the intake base or plenum. Wouldn't be the first time a new part failed or something on a fresh engine came loose.

Caveman305

iTrader: (8)

clogged injectors or a bad vac leak are my bets.


out of curiosity have you done a compression test on the motor?

Tuned Performance

iTrader: (92)

Any progress?