92 LT1 not starting
Thread Starter
6th Gear
Joined: Jul 2023
Posts: 6
Likes: 0
92 LT1 not starting
My dad asked me to make a post to see if you guys could help him out. He took his Corvette to the garage for an oil change and fuel filter replacement and now it won’t start. Just before that he had new injectors, plugs, plug wires and oil pressure gages and it was working perfect and after changing the fuel filter and oil it started once and now it won’t start back. The mechanic tested the coil pack and you can hear the fuel pump and we had computer sent for testing and its working, so we have no idea what the issue could be.
Thread Starter
6th Gear
Joined: Jul 2023
Posts: 6
Likes: 0
Heel & Toe
Joined: Jan 2022
Posts: 15
Likes: 0
From: Ardmore, OK
Have you pulled codes? You can jump pins A and G on the ALDL connector (located under the dash on the driver side) the turn the key to the on position to display codes on the gauge cluster. That would be a good place to start. If you get a code write down the Module number and the code number (e.g. Module 1 C12). C12 would mean no codes.
Thread Starter
6th Gear
Joined: Jul 2023
Posts: 6
Likes: 0
Update: Went to garage to pick it up, put the computer back it after having it tested at SIA and it showed no issues. Put about 4 gallons of gas in it and it fired up and drove it home and that was about 15 miles. Got home and it started back up but after checking it a few hours later its not starting. Thankfully we was able to avoid a towing bill but now its not running, again.
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
You need to verify what is missing. Fuel or spark. Cannot troubleshoot further from there.
Your FPR could have ruptured…your ICM or coil could have failed… your opti could have failed… your fuel pump may be the issue…. Need to diagnose!
Your FPR could have ruptured…your ICM or coil could have failed… your opti could have failed… your fuel pump may be the issue…. Need to diagnose!
Thread Starter
6th Gear
Joined: Jul 2023
Posts: 6
Likes: 0
Update: We tested the codes for the car and are getting C-12 and then H-16. The car will start fine when its cool and then after 10 minutes and getting warm it shuts off. We are full on coolant fluids and the fans are working, would love it if anybody has any suggestions.
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
Heel & Toe
Joined: Jan 2022
Posts: 15
Likes: 0
From: Ardmore, OK
Depending on the Module the H16 code is showing on will give you and indication of which route to follow.
H - history, C - current
Module 1 (CCM) - H16 - Ignition 3 Fuse Circuit. Will always show as a history code because the CCM will not be able to enter diagnostic mode (pull codes) if the fault is current.
Module 4 (ECM) - C16 / H16 - Optispark Ignition Timing System. Very likely the issue. This is your distributor and you will get no spark if it is malfunctioning.
Knowing that the Optispark is a known issue on these cars, especially on the 92-93 non-vented versions I would bet you're seeing early signs of Optispark failure. Verify the module that the code showed on and get yourself a manual. Changing out the Optispark is really not as bad as a lot of people make it out to be.
Also if you need to change the Optispark, now is a good time to replace the water pump as well since you're going to have to pull it off to get to the Optispark
H - history, C - current
Module 1 (CCM) - H16 - Ignition 3 Fuse Circuit. Will always show as a history code because the CCM will not be able to enter diagnostic mode (pull codes) if the fault is current.
Module 4 (ECM) - C16 / H16 - Optispark Ignition Timing System. Very likely the issue. This is your distributor and you will get no spark if it is malfunctioning.
Knowing that the Optispark is a known issue on these cars, especially on the 92-93 non-vented versions I would bet you're seeing early signs of Optispark failure. Verify the module that the code showed on and get yourself a manual. Changing out the Optispark is really not as bad as a lot of people make it out to be.
Also if you need to change the Optispark, now is a good time to replace the water pump as well since you're going to have to pull it off to get to the Optispark
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio