Project Ruby in the Rough
Le Mans Master
Joined: Dec 2005
Posts: 8,561
Likes: 944
From: Communist Colorado
My car would be really hard to start sometimes, start perfectly other times, then not at all other times! The opti was an MSD unit that was about 2 years old with under 5000 miles on it. For a long time I discounted that it could be the problem. Well, it turns out MSD had a run of distributors with bad optical sensors in them. I sent mine into MSD for a rebuild with all new internal parts and new cap & rotor. The problem was fixed...finally!
Thread Starter
Racer
Joined: Nov 2010
Posts: 413
Likes: 2
From: Carencro LA
This morning I pulled the PCM off, opened the case, pulled the chip, reseated the chip, put it back on the car, and it runs. Will wait and see if it keeps running.
Last edited by Geardo; Aug 5, 2014 at 01:50 PM.
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
My 2-cents
The 93 has the infamous non-vented opti spark. Your profile says you live in LA, lots of humidity there, and the non-vented opti DO NOT like the sense of it.
You said the PO installed a new opti.
--When?
--What type?
If I was you, I'd buy a modified vented opti for your 93. The opti is not cheap, and if you go the cheap way buying those ones in ebay you will go back and re-live post #1.
The 93 has the infamous non-vented opti spark. Your profile says you live in LA, lots of humidity there, and the non-vented opti DO NOT like the sense of it.
You said the PO installed a new opti.
--When?
--What type?
If I was you, I'd buy a modified vented opti for your 93. The opti is not cheap, and if you go the cheap way buying those ones in ebay you will go back and re-live post #1.
Thread Starter
Racer
Joined: Nov 2010
Posts: 413
Likes: 2
From: Carencro LA
My 2-cents
The 93 has the infamous non-vented opti spark. Your profile says you live in LA, lots of humidity there, and the non-vented opti DO NOT like the sense of it.
You said the PO installed a new opti.
--When?
--What type?
If I was you, I'd buy a modified vented opti for your 93. The opti is not cheap, and if you go the cheap way buying those ones in ebay you will go back and re-live post #1.
The 93 has the infamous non-vented opti spark. Your profile says you live in LA, lots of humidity there, and the non-vented opti DO NOT like the sense of it.
You said the PO installed a new opti.
--When?
--What type?
If I was you, I'd buy a modified vented opti for your 93. The opti is not cheap, and if you go the cheap way buying those ones in ebay you will go back and re-live post #1.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
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
Instructor
Joined: Feb 2014
Posts: 181
Likes: 2
From: Omaha Nebraska
You might consider a wire wiggling experiment:
Once you've got the car not starting, wiggle wires in one area at a time, and try to start the car after each area.
I'd start with wires connecting to the PCM.
Another experiment would be disconnecting the battery and then trying to restart. To me, this would indicate a bad PCM.
IMHO, this problem has all the symptoms of either a PCM problem or a wiring/connector problem. The trick is to figure out which.
Once you've got the car not starting, wiggle wires in one area at a time, and try to start the car after each area.
I'd start with wires connecting to the PCM.
Another experiment would be disconnecting the battery and then trying to restart. To me, this would indicate a bad PCM.
IMHO, this problem has all the symptoms of either a PCM problem or a wiring/connector problem. The trick is to figure out which.
Thread Starter
Racer
Joined: Nov 2010
Posts: 413
Likes: 2
From: Carencro LA
Got her running
The problem was the PCM, sent it to SIA, and they said it was so bad they couldn't repair it. They sold be another PCM, it was $325 with a 1 year warranty. The car starts right up, no codes, and runs great till it hit's about 190 deg, then it idles at about 1500 rpm, with a slight miss, if you drive it, it runs ok till you go past half throttle, then it surges. let it cool down, and it runs fine again.
Pro
Joined: Sep 2004
Posts: 505
Likes: 1
From: Guntersville Alabama
[QUOTE=Geardo;1587503217]Replaced the ICM, still no start, replaced the coil with a MSD, and replaced the Opti harness, now it starts, idles a little high, but ran it till it was 200 degrees shut down, and restarted several times. I did notice the ASR light, and security light flashed a few
The PCM can be the cause of many problems. Things like the cooling fans coming on before the engine reaches 230f. The fsm is really a good resource for tracking these kind of issues.
FSM factory service manual
93cruiser
The PCM can be the cause of many problems. Things like the cooling fans coming on before the engine reaches 230f. The fsm is really a good resource for tracking these kind of issues.
FSM factory service manual
93cruiser
Drifting
Joined: May 2012
Posts: 1,336
Likes: 15
From: Mechanicsburg PA
Central PA Events Coordinator
St. Jude Donor '12-'13
The problem was the PCM, sent it to SIA, and they said it was so bad they couldn't repair it. They sold be another PCM, it was $325 with a 1 year warranty. The car starts right up, no codes, and runs great till it hit's about 190 deg, then it idles at about 1500 rpm, with a slight miss, if you drive it, it runs ok till you go past half throttle, then it surges. let it cool down, and it runs fine again.
