No Spark about to Burn this Car
Thread Starter
Teching In
Joined: Jun 2015
Posts: 14
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No Spark about to Burn this Car Gents,
I've owned an LT! for 13 years and never had an opti problem.
History of my recent problem.
Currently building a camaro mustang challenge car. I reworked the engine harness to make it a stand alone harness. The motor is completely stock fresh rebuild. Went to fire it has no spark. So I started testing everything I could think of. Engine grounds. Then checked every wire individually. for continuity and for short to ground.
Swapped to a known working PCM. Still same result.
So now to replacing parts. So I took the coil and ICM off of another LT1 camaro (same year). Still not spark.
So I started testing the individual connectors to the ICM and the OPTI Per shoebox how to's:
At the ICM harness
Pin A = 12.07VDC (10 to 12V needed)
Pin B = 0VAC (needs 1VAC to 4VAC While cranking)
Pin C = 0 OHMs of resistance with key off
Pin D = 12.05 VDC
At the opti harness where it plugs into the opti
Pin A = 5.03VDC (needs 5VDC)
Pin B = 5.03VDC (needs 5VDC)
Pin C =12.03VDC (Needs 12VDC)
Pin D = .3 ohms with key off
So I took this as it needs a new opti. Researched optis seems like a crap shoot now with ACdelco being a reman.
Started with just replacing the opti sensor with one off amazon. Still same result above.
Got pissed ran to Jegs and picked up the only OPTI they had in stock. it what their JEGS opti. Heard bad things but wanted to get the car running that day. Same result.
Am I missing something? I do not have an oscilloscope to test the actual wave lengths. I could buy one but figured I would ask what you gents thought before I through any more money at it.
I've owned an LT! for 13 years and never had an opti problem.
History of my recent problem.
Currently building a camaro mustang challenge car. I reworked the engine harness to make it a stand alone harness. The motor is completely stock fresh rebuild. Went to fire it has no spark. So I started testing everything I could think of. Engine grounds. Then checked every wire individually. for continuity and for short to ground.
Swapped to a known working PCM. Still same result.
So now to replacing parts. So I took the coil and ICM off of another LT1 camaro (same year). Still not spark.
So I started testing the individual connectors to the ICM and the OPTI Per shoebox how to's:
At the ICM harness
Pin A = 12.07VDC (10 to 12V needed)
Pin B = 0VAC (needs 1VAC to 4VAC While cranking)
Pin C = 0 OHMs of resistance with key off
Pin D = 12.05 VDC
At the opti harness where it plugs into the opti
Pin A = 5.03VDC (needs 5VDC)
Pin B = 5.03VDC (needs 5VDC)
Pin C =12.03VDC (Needs 12VDC)
Pin D = .3 ohms with key off
So I took this as it needs a new opti. Researched optis seems like a crap shoot now with ACdelco being a reman.
Started with just replacing the opti sensor with one off amazon. Still same result above.
Got pissed ran to Jegs and picked up the only OPTI they had in stock. it what their JEGS opti. Heard bad things but wanted to get the car running that day. Same result.
Am I missing something? I do not have an oscilloscope to test the actual wave lengths. I could buy one but figured I would ask what you gents thought before I through any more money at it.
Through troubleshooting you seem to have eliminated the PCM, ICM, coil, and opti as the culprit. This leads me to believe that you have a wiring issue, possibly corresponding to your reworked harness?
Thread Starter
Teching In
Joined: Jun 2015
Posts: 14
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Year 1995
I made the harness stand alone. I used LT1swap.com as a guide. Ultimately I took 31 pounds of wire out of the car. Hence why I deleted the AC and accessories out of the harness.
The car is going to be a track only car.
I made the harness stand alone. I used LT1swap.com as a guide. Ultimately I took 31 pounds of wire out of the car. Hence why I deleted the AC and accessories out of the harness.
The car is going to be a track only car.
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
Might want to re-visit the wire loom
I think 2 bad out of box opti is way less likely than a potential "oops" in the wire harness diet
maybe a shared signal .5 vdc wire or ground wire that was omitted needs to be restored
has VATS been programmed out?
I think 2 bad out of box opti is way less likely than a potential "oops" in the wire harness diet
maybe a shared signal .5 vdc wire or ground wire that was omitted needs to be restored
has VATS been programmed out?
Thread Starter
Teching In
Joined: Jun 2015
Posts: 14
Likes: 0
I did have the VATS programmed out.
As much as I don't want to I'm going to split the loom and make sure I do not have any shorts. All the tests I have done shows there isn't any shorts but I didn't think of maybe the wires sharing the same source.
I'll do that on Saturday morning and post an update.
As much as I don't want to I'm going to split the loom and make sure I do not have any shorts. All the tests I have done shows there isn't any shorts but I didn't think of maybe the wires sharing the same source.
I'll do that on Saturday morning and post an update.
Trending Topics
OPTI Pin Out Hi Clay, I manufacture both early/late Opti Spark Distributors.
I have sold this item to LS-1 Tech members.
Your use of a Voltmeter has been good.
This is the Pin Out/Signal specification.
A = Low Resolution Signal with FOUR high/low for each crankshaft turn (+5/0) a Hall with my Opti.
B = High Resolution Signal with 180 counts for each crankshaft turn. (+5/0) a Hall with my Opti.
C = 12 Volt Power
D = Power Ground
This test should be done when the engine is cranked.
Report your observarion.
Lance
I have sold this item to LS-1 Tech members.
Your use of a Voltmeter has been good.
This is the Pin Out/Signal specification.
A = Low Resolution Signal with FOUR high/low for each crankshaft turn (+5/0) a Hall with my Opti.
B = High Resolution Signal with 180 counts for each crankshaft turn. (+5/0) a Hall with my Opti.
C = 12 Volt Power
D = Power Ground
This test should be done when the engine is cranked.
Report your observarion.
Lance
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Staging Lane
Joined: Jan 2018
Posts: 75
Likes: 1
Hi Clay, I manufacture both early/late Opti Spark Distributors.
I have sold this item to LS-1 Tech members.
Your use of a Voltmeter has been good.
This is the Pin Out/Signal specification.
A = Low Resolution Signal with FOUR high/low for each crankshaft turn (+5/0) a Hall with my Opti.
B = High Resolution Signal with 180 counts for each crankshaft turn. (+5/0) a Hall with my Opti.
C = 12 Volt Power
D = Power Ground
This test should be done when the engine is cranked.
Report your observarion.
Lance
I have sold this item to LS-1 Tech members.
Your use of a Voltmeter has been good.
This is the Pin Out/Signal specification.
A = Low Resolution Signal with FOUR high/low for each crankshaft turn (+5/0) a Hall with my Opti.
B = High Resolution Signal with 180 counts for each crankshaft turn. (+5/0) a Hall with my Opti.
C = 12 Volt Power
D = Power Ground
This test should be done when the engine is cranked.
Report your observarion.
Lance
Hi lance i have a 95 Z28 LT1 and interested in the omnispark do you have a link
.
OP sorry i subscribe not ment to jack your thread a lot of good advice to follow after modifie LT1ECM stock wiring...
PanteraEFI.COM web site = New Porducts Hi Ghostin, NOT a Hyjack, A "Freejack" = OK
I Believe Clay's Report OR YOUR report will help ALL members.
My site is Panteraefi.com, look under NEW products.
Lance
I Believe Clay's Report OR YOUR report will help ALL members.
My site is Panteraefi.com, look under NEW products.
Lance
Thread Starter
Teching In
Joined: Jun 2015
Posts: 14
Likes: 0
Thread Starter
Teching In
Joined: Jun 2015
Posts: 14
Likes: 0
Gents,
Wanted to thank everyone for chiming in on this. So the problem was not with the harness nor the opti. Since I rewired the entire car using an aftermarket Fuse/Relay block. I had the PCM (pink wires) connected to a circuit that was powered when key was switched on. But shuts power down during cranking. Just like your typical accessories circuit from GM. I was unaware this block had that function. It was difficult to test with just one person.
Moral of the story While cranking the PCM was getting shut down. As soon as I fixed that car fired right up with no problems.
Thanks again for your reply's.
Wanted to thank everyone for chiming in on this. So the problem was not with the harness nor the opti. Since I rewired the entire car using an aftermarket Fuse/Relay block. I had the PCM (pink wires) connected to a circuit that was powered when key was switched on. But shuts power down during cranking. Just like your typical accessories circuit from GM. I was unaware this block had that function. It was difficult to test with just one person.
Moral of the story While cranking the PCM was getting shut down. As soon as I fixed that car fired right up with no problems.
Thanks again for your reply's.
Gents,
Wanted to thank everyone for chiming in on this. So the problem was not with the harness nor the opti. Since I rewired the entire car using an aftermarket Fuse/Relay block. I had the PCM (pink wires) connected to a circuit that was powered when key was switched on. But shuts power down during cranking. Just like your typical accessories circuit from GM. I was unaware this block had that function. It was difficult to test with just one person.
Moral of the story While cranking the PCM was getting shut down. As soon as I fixed that car fired right up with no problems.
Thanks again for your reply's.
Wanted to thank everyone for chiming in on this. So the problem was not with the harness nor the opti. Since I rewired the entire car using an aftermarket Fuse/Relay block. I had the PCM (pink wires) connected to a circuit that was powered when key was switched on. But shuts power down during cranking. Just like your typical accessories circuit from GM. I was unaware this block had that function. It was difficult to test with just one person.
Moral of the story While cranking the PCM was getting shut down. As soon as I fixed that car fired right up with no problems.
Thanks again for your reply's.
Clay = Quality Tech Hi Clay, your work is great, good "tech", BEST reports, not common here at LS-1 Tech.
I offer "best price", help to you, to suite your needs.
YOU have EARNED this on your own, best wishes.
Lance
I offer "best price", help to you, to suite your needs.
YOU have EARNED this on your own, best wishes.
Lance
Registered User
Joined: Aug 2018
Posts: 2
Likes: 0
No spark fix I had to reset my computer after changing out a camshaft sensor do to lost spark on my 2002 firebird. on the GM cars you can reset the computer by disconnecting the negative post on your battery , wait at least 30 min before hooking your battery back up (I waited overnight), turn your key to auxiliary position for two full minutes, next take the key out of the ignition for ten seconds then try starting, This allows your computer to relearn your car, (My car started right up). If your car starts do not rev your car and drive normal the first few drives while the computer is relearning your car. You could also have corrosion at your computer harness that can be cleaned with spray Electrical cleaner from the parts store, Oder test on the computer wouldn’t be a bad idea to see if anything burnt out. If still no spark and you have a security or anti theft light on you might want to YouTube how to bypass the anti theft with a wire. Hope this helps