Hi all. I have a 1996 Firebird Formula with a no-start condition that I am having a hell of a time trying to diagnose and I'm looking anywhere for help.

Relevant information:
-Ran out of fuel on Friday 6/28 (stupid, I know)
-Filled up and ran great rest of weekend
-Sunday, 6/30 started the car, ran fine for ~1 minute and died.
-Since then, crank but no start. Occasionally sputters a little bit at the end of cranking.

I have followed the 1996 Factory Service manual no-start diagnostics with no luck.

Here's the diagnostics I've done:
- The car is not throwing any codes
- Checked fuel injector and fuel pump fuses
- Checked MAF sensor by unplugging it (not faulty)
- Car has spark at ignition coil
- Car has spark at plugs (Confirmed at 3 cylinders with spark tester)
- Will not start with starter fluid
- Fuel pump will prime
- Fuel filter was replaced and did not improve issue
- Fuel pressure is ~42lbs on prime
- Probed fuel injectors to confirm all are getting signal
- Fuel injectors are spraying fuel
- Front 4 injectors have been replaced with no improvement.

Do not suspect opti issue as it was replaced last summer and I have spark at plugs.

I have not checked compression or timing and am afraid that will be next step. I am at a complete loss and looking for ANY advice on what to check, what I might have missed, anything. Thanks in advance.

 

I’m not an LT1 expert. The following is guesswork that I know is reasonable on an LS1 car.

Maybe a throttle issue? Will it start and stay running if you hold the pedal down a bit? (Don’t floor it; see if you can hit 2000rpm.)

If that does it, check your TPS and IAC.

 

Where did you get the OPTI???

 

Opti is from Petris Enterprises

 

Petris did have a batch of bad optical modules about a year ago, based on feedback from someone here. They replaced failed units for free.

If the Opti fails to the extent that it isn’t producing both the low res and high res pulse signals, P1371 for loss of the low res pulse from the Opti can’t set, because the PCM counts the revolutions of the engine without a low res pulse, by counting the pulses from the high res circuit, and there are no pulses.

After the fuel pump primes for 2 to 3 seconds and shuts off, how fast does the pressure drop?

How did you “probe” injectors to confirm pulsed ground from PCM?

Somehow I recall asking some of these questions already. Did you post on another forum?

 

If it doesn't fire with starter fluid, then fuel isn't the issue!

 

If this were the case, would I be getting spark to the plugs? I can't speak to the quality of the spark once it hits the plug but I at least know that spark is being sent through the wires.

Have not tested for longer than a minute or so, it is on my list.

I used a noid light to confirm.

Correct, also posted on the Firebird forum. Like I said, I'm lookin everywhere for advice. Thanks for the reply