My '92 doesn't have ignition or LCD display on the dash. The ECM has been back to SIA a few times, but the Vette is still stuck in the driveway. Here's a timeline of how my problems came along.

Any advice and experience you can offer is greatly appreciated.

A year ago, I got SYS blinking with no codes, security light flashed, then started to loose ignition. Sometimes would not crank either.

I sent the computer into SIA Electronics. When I recieved the computer, the only problem left was that the speedometer was messed up(Said I was going 12 mph on highway while traveling 72).

A few months later, the display started to go out. It would display very random things and act very glitchy. The display would actually fluctuate(ie Every LCD would light up on display) when you would hit a bump on the road. Most of the time, nothing would be on the display.

That went on for a couple months, then about two months ago, as I was pulling into the driveway, the car died. I started it up and it ran horribly. I let it sit outside for awhile. When I came back later, it started up just fine.

I pulled the computer and sent it back to SIA. When I got it back, the display worked. I went to start the car, and it would just crank, no spark, but there was fuel smell out of the exhaust. With hope, I came out the next day to try to start it. The display was not working and still no firing.

I sent it back. I got it back today. Still no display and no fire.

I called SIA and talked to the ECM manager. He said that they went through the entire computer replacing things that had a hint of poor voltage.

What else can be wrong besides my computer?

The manager is sending me a list of things to perform voltage tests on and is e-mailing me diagrams and directions on what to do.

Thanks in advance -- Brandon

 

I had one wire on the harness to the ecm on my 88 that was cracked with one or two threads of wire connecting it, thus intermittent problems. I fixed that and put a new ecm in it, and the person I sold it to has been driving it trouble free since. Perhaps the Prom may be bad? these electrical problems are a real headache on these cars. I have a 92 I think with a bad O2 sensor , turning the fans on and off, and making the SES light come on constantly etc. Check the little stuff first, fuses (try a few different ones), loose wires, connections etc.

 

I talked to the guy at SIA again, and he said to check for continuity through coil pack etc. So i pulled the plug off of the top of the Optispark, spun the engine a couple times, and it had spark.

So I have fuel smell out of the tail pipe and I have a spark going into the Optispark. The engine just spins, no coughing or sputtering.

Is there anything else that I can check?

I have a feeling that it may be the Optispark.

I also noticed that whenever I closed my door, the LCD would glitch. I am assuming that this is a shorted/loose wire. Where is the best place to check for failure?

I appreciate the help.

-Brandon

 

Stock opti or replacement?
If replacement check the wiring fron the connector on the passenger side of the intake to the opti.

Age of ICM and coil?

Check the ecm fuse

Thats all I got right now

 

- Opti is stock.
- Wiring from passenger side intake to opti looks good.
- Not sure about age of ICM and coil. Everything looks either stock or like its been there for awhile, and it has ~140K.
- The ECM fuse is ok. So are fuses for fuel pump, injectors and coil.

I pulled 3 spark plugs -- the 3 on the passenger side that are easy to get to -- and all 3 spark when the engine cranks. The sparks are a little red, vs blue, probably a sign the plugs need to be replaced. Now I'm really confused...............

* I smell gas in the tailpipes
* I smell gas on the spark plugs
* At least 3 plugs are sparking
* Took the air cleaner off to ensure air-flow

But when the engine cranks, there's nothing that suggests there's any combustion going on in the engine. The only sound it makes after cranking awhile is a jerk/thud, but it doesn't sound like the engine firing. I assume that is something like a compression release.

Gasoline and spark -- but no combustion. Any suggestions?

Whats the best way to see if it has enough fuel flow?

Is there any chance that the timing on the opti could be off badly enough for it not to fire? Seems like it would at least backfire after cranking for awhile.

Thanks
-Brandon

EDIT: I dobut it, but is there any possibility that ECM could be the culprit?