1996 Z28 M6 w/traction control.

Overview of my issue: I was on my way to work, set the cruise at 45mph going through a 3 mile long work zone, and then downshifted to get back up to speed. Engine started to break up, then lost power, kinda sputtered for a few seconds then quit... tried cranking 3 seperate times with no luck.

Got the car towed back to my place, and i can see nothing obviously out of place. All connectors that i can see are all on snug, no fuel leaks, nothing obstructed etc. The opti is approx 2 years old, and I have taylor OTVC wires that are 1 year old. The coil has never been replaced as far as I know. No major mods, all in the signature.

I tried to start it again today after it was cool and lo and behold, it started. It ran with a hiccup, then started to idle very very low, almost dieseling. I immediately shut it off and haven't touched it since. I noticed raw fuel was sprayed out the exhaust and spattered onto my garage floor. The tow truck operator who's also a good friend and local mechanic said he used to replace the coil wires left right and sideways on all the old caprice police vehicles and it might be my issue.

This is an easy fix and can be done pretty quickly, I just wanted to get others opinions as to what it might be from others who may have experienced this problem.

Any ideas?

Thanks for your time,
Tim

 

Sounds like a good candidate for a new opti, but do shoebox's coil test first and make sure that's not your issue. Coils and coil wires don't seem to go bad all that often on these cars, but it is a possibility, so you do want to check.

 

You're referring to the "coil continuity test" on shoebox's site?

 

also tighten all the electrical connections from the battery to the red junction box, etc. same happened to me after some wiring work on my car. found a nut at the junction box was loose

 

Get is scanned for codes. The codes for the Opti pulse patterns don't seem to turn on the SES light. If you lose the low resolution pulse the PCM will shut down the fuel system. If it is an intermittent loss of low res pulse, check the Opti. harness connectors for corrosion or damage pins

 

Ok, I don't have a scanner, probably a good time to buy one. I'll check all those connections and get back to you, it might not be until tuesday though, that'll be my next day off.
Thank you for your help so far!

 

Also, check for fuel pressure! Pump might be going out.

 

dead opti, or soon to be would be my guess

 

Good and bad news.

Good news is I did a continuity test on the coil, and it passed with flying colors. 5750 ohms all three terminals. I have power to terminals A&D on the ICM harness, both ~10v DC.

I have a feeling it's the optispark, as the AC voltage on the ICM harness shot to 1.25v the first cycle, and then hovered arond .2 volts the rest of the time while cranking, well below shoebox's acceptable range of 1-4v.

*sigh* another 400 bucks flushed... any experience with aftermarket opti's that someone can recommend? This OEM GM unit lasted and astounding 30k miles. Not about to do it again for that little time!

Thanks for your time again!

 

Got under the car to change out the optispark yesterday, was a successful swap with a only a few scratches and some spilled coolant, no major problems.

I did however find out why my old one failed... as soon as i unhooked the old opti and maneuvered it out from the car, the PCM connector ended up facing the ground, and all this nasty, rust/blood colored fluid came pouring out of the connector. It looked like the floor at a butcher, it was that nasty. Turns out the weatherpak didn't make it back on the connector the last time it got changed and let all sorts of nastiness inside, no doubt fouling the **** out of it. I ended up stealing a weatherpak off my truck from a connector that wasn't being used that fit, and hopefully it will die of natrual causes this time instead of getting contaminated!

Tim