Another Optispark ?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
As mentioned, I would check the coil, and the ignition including your ICM. Usually though, a bad ICM results in a no engine start, but it may be intermittent defect in this module. You can have the ICM checked out at your local Autozone, or other automotive chain....
And Casey is very knowledgable Vett-a-holic, follow his advice!! I don't think there is a cure for his love of these machines.....
Intermediate
Joined: Mar 2005
Posts: 44
Likes: 0
From: Orland Park area IL
I've got the same symptoms with my 94. Been too busy to work on it but my research has given me some direction on possible ideas areas to look at.
- the famous opti spark
- coil
- icm
- ecm
- loose or bad connections on cables and wires.
Please post your findings. Maybe in the next few weeks ill get under the hood and start working on this problem.
- the famous opti spark
- coil
- icm
- ecm
- loose or bad connections on cables and wires.
Please post your findings. Maybe in the next few weeks ill get under the hood and start working on this problem.
Thread Starter
Advanced
Joined: Nov 2006
Posts: 66
Likes: 0
From: Wyoming
Ok, here's what I found. I got down to the cap and rotor. The cap is full if carbon tracks. One spot had a hole starting it was so bad. So I'm not changing out the optispark at this time. I 'm going to use that money for my ring and pinion (probably be going with 3.73). When the time comes to change it I will go with the MSD. For now a new good aftermarket cap and rotor should get me going, "I hope". I had no problems removing everything other than finding a E4 torq socket. It took longer finding the E4 than removing the cap. Luckly a friend had one. None of the parts stores had anything close. So I will be ordering a couple of them for the future. Thanks for all the help and suggestions, and I will keep you guys updated with this.
Thanks,
Steve
Thanks,
Steve
Thread Starter
Advanced
Joined: Nov 2006
Posts: 66
Likes: 0
From: Wyoming
Ok, I was wrong on this one. Here is the codes I got. c12, c42, c51, c61, h42, h51, h61, h62. So I have a few more problems to deal with I guess.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
What modules were all those DTCs in??? That is important. All those codes mean a totally different thing in each different module.
DTC 61 is not even a Module 4 code at all.
DTC #51: EPROM Programming Error. (Assuming Module 4) You really need to find out about this and which module number its in.
Id say that if your cap and rotor are that bad, id have a guess at the fact that none of those codes are related to that. Really important you find out what module they were in so we can help you to correctly diagnose all the issues.
DTC 61 is not even a Module 4 code at all.
DTC #51: EPROM Programming Error. (Assuming Module 4) You really need to find out about this and which module number its in.
Id say that if your cap and rotor are that bad, id have a guess at the fact that none of those codes are related to that. Really important you find out what module they were in so we can help you to correctly diagnose all the issues.
Safety Car
Joined: Jan 2004
Posts: 4,549
Likes: 343
From: Glastonbury CT
opti spark
I bought from Gordon Kilbrew the C4 Guru his testing modules. I had the same problem since day one. When i brought my vette back from the dealer it back fired for the first 15000 miles. For the last six months it has stumbeled aftewr it went into the closed loop. It also started quickly but idled eracticaly. I found a code 33 and replaced the MAP. Used a Wells part from auto zone could not find a GM replacement. The car runs like a bear know but i beleive this is just the begining of the poor design of this C4. My car is a show car pampered in a garage one driver ordered new never beat on. I spend more time reading the service manual then with my wife. 
Thread Starter
Advanced
Joined: Nov 2006
Posts: 66
Likes: 0
From: Wyoming
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
C12 will only ever appear in module 1 and is NOT a DTC.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High relates to the temp sensor in the front of the water pump. Test this part.
Thread Starter
Advanced
Joined: Nov 2006
Posts: 66
Likes: 0
From: Wyoming
That question was not to you, my previous post was for you. WOT means WIDE OPEN THROTTLE and has nothing to do with DTCs.
C12 will only ever appear in module 1 and is NOT a DTC.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High relates to the temp sensor in the front of the water pump. Test this part.
C12 will only ever appear in module 1 and is NOT a DTC.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High relates to the temp sensor in the front of the water pump. Test this part.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Nah mate, the WOT question was for the other guy.
The codes youve got from Module A are all related to the airbag system. Module 9 is the ABS/ASR system
Id say your whole problem with your engine issue is related to the bad cap and rotor you found.
The codes youve got from Module A are all related to the airbag system. Module 9 is the ABS/ASR system
Id say your whole problem with your engine issue is related to the bad cap and rotor you found.
