94 LT1 battery light & check engine light on
Thread Starter
Intermediate
Joined: May 2009
Posts: 28
Likes: 0
94 LT1 battery light & check engine light on
Hi, everyone
94 LT1 won't start
I replaced the battery with a yellow top optima; had a red top before. Cleaned both positive & negative battery terminals. Cleaned & checked wires coming & going to the fuses in the engine compartment & alternator. Replaced alternator & ignition control module also had the coil checked it is fine. I checked for spark on plugs & wires No Spark. After everything I've checked or replaced the Vette still won't start; it tries but no Cigar. The battery light & check engine light remain on. Please Help.
Any wisdom will be greatly appreciated.....Thank You.
94 LT1 won't start
I replaced the battery with a yellow top optima; had a red top before. Cleaned both positive & negative battery terminals. Cleaned & checked wires coming & going to the fuses in the engine compartment & alternator. Replaced alternator & ignition control module also had the coil checked it is fine. I checked for spark on plugs & wires No Spark. After everything I've checked or replaced the Vette still won't start; it tries but no Cigar. The battery light & check engine light remain on. Please Help.
Any wisdom will be greatly appreciated.....Thank You.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Your stating at least 3 problems in your post. Alternator, engine light and no spark at plugs (no start).
Would like to know what problem occurred first and what you focus is on. I assume it is the no start problem. The alternator will not affect the spark. Did you check for spark off the coil and not just the plugs. Can you check your fuel pressure or injector pulses at the injectors?
You will get a battery light and check engine light if the engine is not running......
Here are some items to check in no particular order since there is limited information so far.
Fuses: fuse 25, coil: fuse 14 fuel pump: fuse 22 & 23 injector voltage: fuse 33 PCM.
It would be nice to know if there is 4 VAC driving the ICM from the PCM.
If you have a check engine light on before you could not get it started, then you should check for codes and see what codes have triggered the light.
Just wondering, did you replace the battery and alternator in hopes of getting the engine stared?
Would like to know what problem occurred first and what you focus is on. I assume it is the no start problem. The alternator will not affect the spark. Did you check for spark off the coil and not just the plugs. Can you check your fuel pressure or injector pulses at the injectors?
You will get a battery light and check engine light if the engine is not running......
Here are some items to check in no particular order since there is limited information so far.
Fuses: fuse 25, coil: fuse 14 fuel pump: fuse 22 & 23 injector voltage: fuse 33 PCM.
It would be nice to know if there is 4 VAC driving the ICM from the PCM.
If you have a check engine light on before you could not get it started, then you should check for codes and see what codes have triggered the light.
Just wondering, did you replace the battery and alternator in hopes of getting the engine stared?
Thread Starter
Intermediate
Joined: May 2009
Posts: 28
Likes: 0
Thanks for replying and the knowledge.
I'm trying to give as much info as I can sorry if I've confused you.
the car was driving fine; then it started stumbling & shifting very hard @ 3grand. Then the service asr light & check engine light came on so I parked her. Then it wouldn't start up anymore; so I checked for code's. It gave me code H64 = RF O2 Sensor Lean; I cleared it. Yes I checked the coil for spark there's non I had the coil checked out at the auto parts store and they said it was fine. Yes I did replace the battery, alternator, and the ignition control module in hopes that it would start.
I checked the fuse you told me with a test light and there fine but these didn't light up on both sides............
1 a/c, 5 htd Mir, 7 horn, 9 crank air bag, 10 crank p/n clutch, 11, rh illum
12 lh illum, 13 cnsl illum. I don't know if this has anything to do with it.
Hope this info helps. Thank you.
I'm trying to give as much info as I can sorry if I've confused you.
the car was driving fine; then it started stumbling & shifting very hard @ 3grand. Then the service asr light & check engine light came on so I parked her. Then it wouldn't start up anymore; so I checked for code's. It gave me code H64 = RF O2 Sensor Lean; I cleared it. Yes I checked the coil for spark there's non I had the coil checked out at the auto parts store and they said it was fine. Yes I did replace the battery, alternator, and the ignition control module in hopes that it would start.
I checked the fuse you told me with a test light and there fine but these didn't light up on both sides............
1 a/c, 5 htd Mir, 7 horn, 9 crank air bag, 10 crank p/n clutch, 11, rh illum
12 lh illum, 13 cnsl illum. I don't know if this has anything to do with it.
Hope this info helps. Thank you.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Obviously you have a no spark problem. I would guess based on limited information that the ICM or opti may be the problem (I would think ICM first). If you can check the injector pulses to see if there good, then that would indicate the opti low resolution pulse is clocking the PCM and driving the injectors (then the opti is probably good).
(If there is no injector drive, then the opti may be bad.)
I would assume then that the drive for the ICM is being developed. In that case I would at least get the ICM checked or replaced with a GM part.
(If there is no injector drive, then the opti may be bad.)
I would assume then that the drive for the ICM is being developed. In that case I would at least get the ICM checked or replaced with a GM part.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Go to a auto part store and get a noid light. You connect it across the electrical connections of the injectors. You are not checking the injectors, you are testing to see if it is being driven by getting drive pulses from the PCM. One wire has 12 volts on it all the time and the other goes to ground thru the PCM when pulsed (requested). You have to test it when you crank the engine.
Do you have a DVM or the FSM manuals?
I re-read the post and see you have already repalced the ICM. You might then have a opti problem but would not run with it quite yet. There is still lots of other things to check.
Do you have a DVM or the FSM manuals?
I re-read the post and see you have already repalced the ICM. You might then have a opti problem but would not run with it quite yet. There is still lots of other things to check.
Thread Starter
Intermediate
Joined: May 2009
Posts: 28
Likes: 0
Thank you.
I'll go to an auto parts and get a noid light. I've been looking for my manual can't find it; so I'll have to see if they have one there. I'll check this out and get back to you. One more question is there a specific way of checking the spark off the opti?
I'll go to an auto parts and get a noid light. I've been looking for my manual can't find it; so I'll have to see if they have one there. I'll check this out and get back to you. One more question is there a specific way of checking the spark off the opti?
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
Thread Starter
Intermediate
Joined: May 2009
Posts: 28
Likes: 0
@pcolt94.
I know I've been MIA for awhile sorry I was in and out of the hospital. Feeling better though. Anyways I found my repair manual. Then while I was at the hospital a friend of a friend who works for Chevy down here. Took a look at it and said the opti got wet and fouled out. I ordered the msd with the adjustable timing screw. Can you give me any feed back on it?
I know I've been MIA for awhile sorry I was in and out of the hospital. Feeling better though. Anyways I found my repair manual. Then while I was at the hospital a friend of a friend who works for Chevy down here. Took a look at it and said the opti got wet and fouled out. I ordered the msd with the adjustable timing screw. Can you give me any feed back on it?