white94vette

I suppose a little intro into my problem is required first.

I took the car to the track a few weeks ago and was confronted mid day by what seemed to be a fuel starvation problem. The car would buck real hard, then I noticed that this only happened above 3000 rpm and had little to do with where I was on the track, hence it was not a fuel problem. I was able to drive the car home the 100 miles w/o any major issue and the problem only came about when I pushed the car hard. A few days later, I pushed the car again and this time it simply died. Figuring it was ignition related I checked for spark which was not found. I took it to my corvette mechanic who confirmed the lack of spark and suggested that the opti-spark be replaced.

Now the brand new opti-spark unit is installed (modified to properly vent the unit using the 95-96 vac assy) and I still have no spark??? I checked at the plug...no spark. I pulled opti-spark end of the coli-opti wire and checked for juice but nothing. Since there is no juice going from the coil out to the opti-spark, that means its either an issue with the low voltage side of the opti-spark (it does send signal to back to the ignition....??) or its something else all together.............

Now Good People of the forum, my eyes and ears are open for your thoughts.

Nathan Plemons

Well since you had the same problem with the old and new opti I'd say you need to look somewhere other than there for your problem. It sounds a lot to me like your ignition control module has crapped out. This costs about $50 new and can be replaced in just a few minutes. Furthermore it should set a code if it's the problem, just put a scan tool on it and see what it says.

It sounds like you're the victim of another "oh the opti is supposed to be a weak spot on these cars, thus it must be the problem" mechanic. I wish I had a count of how many opti's have been replaced when they had nothing to do with the problem. After doing the same thing myself on two different cars I've learned to actually look at the opti LAST when troubleshooting an LT1 ignition problem. On my car once it was a corroded connection, on a friend's car it was a 10 amp fuse! We replaced a $200 distributor over a $.10 fuse!!

It doesn't take too much of that before you start to wise up.

white94vette

Thanks for the info. Seems you may be right and I wish I had your version before I tore apart the front of the car. I reviewed the Chevy Maunals I had and verified that the low voltage (1-5V) Signals from the opti-spark were indeed being sent. I was hoping it was just the coil (since I had the original), but after the swap it still didnt work. Final test was to see if terminal "C" on the connector to the Ignition Control Module was grounded and yep, it is...........now I'll go down and buy a $60 ignition control module and pray that fixes the problem.

By the way, just a note to anyone who goes off to the mechanic and hears that his or her opti spark is bad.....Dont take their words for it, test the low voltage output from the opti-spark. Well, that or just hand over your wallet and cover your eyes.

Nathan Plemons

Well, on the plus side at least you've got a brand new opti. Glad to hear it worked out for you. When my ignition control module went out I pulled my hair out trying to figure out the problem. I thought it was related to my remote start. After I ripped that out and I still had the same problem I was really pissed.

I finally wised up and looked for trouble codes. Sure enough it was code 24, or 42, can't remember exactly, EST grounded. I went through the troubleshooting in the manual for this problem and came up with what had to be a dead module. I was able to get one from a friend, it fired right up and has been running great ever since.

onedef92

Don't forget to apply a thin layer of Dielectric Grease to the underside of that ignition module before you install it or it'll die a horrible death in little time at all...

white94vette

Yeah, all is not a loss....and I still have to verify that the ignition control module is the problem (the new one comes in today....I have my fingers crossed that she fires up once again). On the plus side, I did spend a lot of time with my baby....under her, over her, and who knows what else...I think my wife was starting to think I'd never come back inside the house w/o smelling like oil and road grime. I did get the opportuinty to do a lot of work on the car in the time it was up on the jacks. Oil Pan Gasket, Front Cover Gasket, Power Steering Pump, etc......now I got to get all the new hoses for the coolant system. The main ones are no problem, but it seems the dealer is the only option for the ones going back to the heater core.

I'll either post back a real happy man with a wife who is similarly happy, or a man who now will just break down and move into the garage....any one have a spare heater?

James94LT1

Hope the module works for you! I was plagued with opti issues after my head/cam swap. I went through 5 in no time. Finally realized it was high rpms mixed with a MSD 6AL box and coil that was causing the rotors to self destruct in no time. But each time I would go through the easier checks like: 1) check for spark 2) coil wire swap 3) ignition module 4) new opti

I finally got so tired of it I went to an LTCC setup with the LS1 coils.

Goodluck!

REDC4CORVETTE

You at least did the vacum up grade and I am not sure what you mean by moduel or something but you might want to check the power wire to the coil that runs along the intake on pass side ,or the alt wire that runs on drivers side upper intake,both will cause the car to not start and all dash lights will come on and no start condition.

Gooseit

I got all my hoses including the heater hoses for my 95 coupe at O'riellys auto parts. Try their before the dealer.
Good Luck
Goose

white94vette

Well, after a 5 minute install, the new Ignition Module started the car right up! Next time anyone tells you that you have a bad Opti-Spark, do not take their word for it.....test the low voltage output from the opti spark....if its there...chances are the opti spark is good.

Thanks for all your help members.

onedef92

Great. Did you remember to coat it with a thin layer of dialectric grease as I stated earlier?

bogus

I have been saying that for a long long time!

The opti is just a convenient target for abuse...

BrianCunningham

Pull the codes and see if your getting the signals through.

Check the leads, some have been getting a lot of build up on them.

You might also have a bad coil.