Its been a while since I've made a post but I need direction on these electrical issues I currently have. I recently picked up a 1988 Camaro Iroc-z , Vin #8. was originally optioned with the 350 Tpi. The car had been swapped with an LT1. Its either a 1994 or 1995. Im not too sure. The owner I bought it from didn't know. ECM service #16188051. The owner before me had removed the gas tank and fuel sending unit because he said the fuel pump was bad. The water pump had been removed and the mounting bolts were missing. The owner said the optispark notorious for going bad and he was in the process of changing it out but lost interest. The owner didn't have the keys but the cars ignition cylinder turned freely without a key... I don't know why. I haggled the owner down to $250 for the car. He threw in a new Spectra fuel Tank and fuel sending unit.

So I got the car home and changed out the fuel filter, fuel pump, fuel sending unit, and fuel tank. Connected the sensor at the water pump even if it was not not installed. I gassed up, and turned the ignition cylinder. The car cranked over strong but did not start. I didn't hear the fuel pump and my first thought was to check the fuses and fuel pump relay. The fuses were good, even the 20a fuse on the passenger fender. I checked the shrader valve and had no fuel pressure in the fuel rail. I put 12v on ALDL terminal "G" and the fuel pump primed. I checked the shrader valve again and had fuel pressure in the rail. Cranked it over again but still no start. changed ICM since I had an extra one. Still. no spark. Im at a loss right now.
1) Could it be the LT1 ecm being bad?
2) A problem with the ignition at the column?
3) Could a bad optispark interfere with the fuel pump not getting signal? or is that two different issues?

I sent a message and an email to user Pocket to possibly make me a new lt1 wiring harness but haven't received a response.

 

need to verify vats is disabled either in the pcm tuning or an external resistor of the correct value of the original LT1 key chip that came with that pcm.

 

Assuming VATS is the same on that ecm as it is on the third gens, it does 2 things when it's not getting the right signal from the key to the VATS module: interrupts the starter connection and disables fuel injector pulse. Sounds to me like your starter has already been bypassed, but if it's just a stock ecm, it still won't fire those injectors without a square wave from the VATS module.

You can defeat it easily two ways: reprogram the ECM to disable the need for the square wave, or emulate the signal with one of these:

https://www.ebay.com/itm/28270041228...EAAOSwXQpeq1fC

 

Update. Installed Vats bypass to connect to the Lt1’s ecm. Still no start.

Noticed ignition switch at the steering column was fried. Changed it out and now the fuel pump primes on its own with the key on. Still no start.

there is spark. Tested by grounding spark plug while it was connected to the wire and while cranking.

Decided to tap on the fuel injectors and engine started sputtering while cranking. No start.

cleaned fuel injectors and changed out o-rings. Still just sputtered and backfired. No start.

removed plugs and noticed fuel on them. Cylinder #7 wire was melted on the exhaust. Going to change out the plugs and wires tommorow. Purchased NGK IX T55’s.

 

So installed new spark plugs. New wires. New Icm, and coil, new optispark. Still no start. It attempts to. It cranks over…sputters and when I shut it completely off (key off) it turns over like there’s some combustion and shuts down. There is a fuel smell coming from the Intake/throttle body. Fuel on the new plugs and slight black coloring/ carbon on the new plugs. I’m at a loss right now.
It seems like it’s off timing. Apparently, the timing is adjusted through the ecm on these lt1’s. what can I be missing? Should I send the ecm to a specialist to tune it?

 

disable fuel pump and spray starting fluid into the throttlebody and crank it. if it runs, get a set of injectors. they could be leaking, or not working at all.

 

Thanks for the reply. I have tried to start it with starting fluid. Didn’t work. I don’t think I had the injectors or fuel pump disabled though. ill do that when I get back today.i have to recharge the battery again. All this attempting to start it kills the battery. Brand new battery by the way. I was planning to check compression and fuel pressure too

 

also thought of something else if you havent checked already- if it is an early optispark with splined drive, it is possible to install it incorrectly. there is a spot where 1 spline is missing, and that will need to go correspondingly into the matching slot in the timing gear. installed incorrectly, it would be out of time at best, or not run at all. and probably damage the opti.

 

thanks for your reply’s. I got good news. The car starts now. I decided to check the optispark. I had installed the new one late one night(while drinking mind you). It’s the vented optispark with clover style insert. I could have sworn I put it on correctly… anyway I put it back on and it fired up. The Motor sounds good. But now the thing is it runs good for about 3-4 seconds and shuts down. If I start it again it will start right up but only run for 3-4 seconds and shut down again. It will keep doing this. I don’t have the water pump installed while I do that. Only the sensor on the pump. What could be telling the motor to shut itself down. A sensor? I’ll do some research on here. Thank you for your help