Good Morning everyone an Happy Memorial Day Weekend.

Finally my c4 (96) was ready for the weekend! (not relay apparently).
After a major 3 days of work on the Optispark replacement , everything looked fine, engine was running like silk, making all the good noises that one would expect from a health LT1 engine! But last night, after a 50 or so miles drive the engine died while on idle from just a block of my house, it started right after and the died again, this time it was harder to start, but it did and I was able to park my baby in the garage. This morning , after hooking the car to the computer I’ve found 2 codes on stored on the car.
P0102 mass air flow circuitry low frequency and P0372 ICM 24x reference circuit missing pulses.
Now here is the strange part… when the key is on the “ON” position (engine not running) lots of strange noises are happening on the engine bay.
1. the air pump cycles on and off
2. fuel pump cycles on and off
3. noises that sound like an shot circuit of some kind.
Isn’t this curios?
If I clean the codes on the computer they come back (even if the engine is not running)
I’ve unplugged everything from the ignition system and the problem seems to occur only when the optispak harness is plugged in. (harness is in good shape and the terminals are clean.
What could have happened to the optspark to cause this weird problem? (Hope is not the PITA optspark!)
Open for Ideas, Suggestion, Miracles……
thanks.

 

Might be but I would clean and check all connections on you coil and icm. Did you mess with the icm and not put thermal grease on it? And clean and check battery connections and your water temp plug on your water pump. Could sealer on the pump sensor mess it up? And thing do cycle with the key on.

 

Although I can offer no help on this. Glad to see someone from the same city on the board.

 

Find a few more and perform a exorcism.

 

thanks for the quick reply.
I did use the special computer geese for the ICM and the all the terminals are clean, but what could be happening to the optispartk the would cause this with the engine off? and if I disconnect the opti harness all the clicking and noises goes away....

 

Thanks DaveP85c4
looks like is a bad optispark then.
looking forward to an other fun weekend!!!!

 

Sorry for the issues, at least if it is the opti you know how to change it

 

That's right.
I just wish that it could be something else like some kind of short outside the optispark...

 

What kind of opti MSD? All wires clicked twice with install?

 

I did change just the cap and rotor because the rest looks like it was in good shape, and all the wires clicked twice.

 

Did you silicone the cap and use locktight on it? Might have gotten some sealer messing things up or the screws just came loose.

 

sure did....too many horror stories....

 

I used red locktight on the screws what did you use?

 

blue treadlock for the screws and clear silicone for the cap

 

Thanks for all the help.
Just got a new accell optispark and I'm installing it tonight.
I'll keep everyone posted.