LT1 No Spark
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Registered User
Joined: Aug 2010
Posts: 2
LT1 No Spark
Hello All,
I've got a LT1 in a 1994 Camaro Z28 A4. I just finished doing a head gasket job. Thanks for all the info from all the posters of this and other forums!!! It made it real easy. The car did run prior to the tear down. The water pump and Opti were not removed.
I am trying to trouble shoot no spark. Here is what I have tried and the results thus far.
No Spark to #1
Checked and Recheck all connections.
Checked all fuses.
Checked and have 12 volts at end of coil wire going into Opti.
Checked opti wiring harness per http://shbox.com/1/4th_gen_tech2.html#opti_test
Red/Black wire has 5.01 DCV and Pink/Black has .02 DCV this is with ICM disconnect per testing at shbox. The results are the same with ICM connected.
Thing that is getting me right now is that it is the same volt readings with or without opti harness plugged into the Opti.
Is this the normal volts reading for the opti harness without the Opti plugged in and the Opti is dead hence no volts at 10DCV per shbox article? or is there something else going on?
Ideas? I'm thinking dead opti, may have gotten some antifreeze on it when separating head from block?...speaking of any suggestions where to get a real GM one? Lowest I got quoted for so far for a non vented was $435.00
Thanks!!!
__________________
1994 Camaro Z28 A4 - Mods, KN Filter, 160 Stat, TB Bypass. Trans- 3000 Stall, Corvette Servos and Heavy Duty Clutch Pack.
I've got a LT1 in a 1994 Camaro Z28 A4. I just finished doing a head gasket job. Thanks for all the info from all the posters of this and other forums!!! It made it real easy. The car did run prior to the tear down. The water pump and Opti were not removed.
I am trying to trouble shoot no spark. Here is what I have tried and the results thus far.
No Spark to #1
Checked and Recheck all connections.
Checked all fuses.
Checked and have 12 volts at end of coil wire going into Opti.
Checked opti wiring harness per http://shbox.com/1/4th_gen_tech2.html#opti_test
Red/Black wire has 5.01 DCV and Pink/Black has .02 DCV this is with ICM disconnect per testing at shbox. The results are the same with ICM connected.
Thing that is getting me right now is that it is the same volt readings with or without opti harness plugged into the Opti.
Is this the normal volts reading for the opti harness without the Opti plugged in and the Opti is dead hence no volts at 10DCV per shbox article? or is there something else going on?
Ideas? I'm thinking dead opti, may have gotten some antifreeze on it when separating head from block?...speaking of any suggestions where to get a real GM one? Lowest I got quoted for so far for a non vented was $435.00
Thanks!!!
__________________
1994 Camaro Z28 A4 - Mods, KN Filter, 160 Stat, TB Bypass. Trans- 3000 Stall, Corvette Servos and Heavy Duty Clutch Pack.
Thread Starter
Registered User
Joined: Aug 2010
Posts: 2
Thanks for the fast response!!! 
I was testing the wrong terminal A and D of the harness. I was testing opti side not ICM side.
Rechecked ICM pigtail and 12.24 DCV at A & D. Now moved onto the AC volt pulse test and there is none.
I was testing the wrong terminal A and D of the harness. I was testing opti side not ICM side.
Rechecked ICM pigtail and 12.24 DCV at A & D. Now moved onto the AC volt pulse test and there is none.
Last edited by 01Fast; Aug 18, 2010 at 10:55 PM.
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Joined: Nov 1998
Posts: 71,098
From: Hell was full so they sent me to NJ
The Opti harness doesn't even connect to the ICM. It connects to the PCM. The PCM sends the pulse signal that tells the ICM to fire the coil, on the single white wire to the ICM.
Shoebox has a diagram of the system:
http://shbox.com/1/95_ign_system_schematic.jpg
Shoebox has a diagram of the system:
http://shbox.com/1/95_ign_system_schematic.jpg
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