Need Help - Possible Misaligned Opti Spark?
Thread Starter
Drifting
Joined: May 2002
Posts: 1,530
Likes: 1
From: Houston TX
Need Help - Not the Opti but Coil Problem???
I just swapped the Opti Spark in my 95 LT1 with a fresh GM one. Car is now misfiring and seems to be out of timing. Does anyone have experience on the new 95 vented Opti install? I am quite sure I got the keyway in the Opti lined up right. For those familiar with the 95 set-up, there are "slots" between each of the three bolt head releifs on the back of the Opti. One of them is a square configuration whereas the other two are a "figure eight" shape. I assume the only way the Opti can go in is by lining up the square slot with the keyway. :confused:
[Modified by aggie88, 10:51 AM 5/18/2004]
[Modified by aggie88, 10:51 AM 5/18/2004]
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: Need Help - Possible Misaligned Opti Spark? (aggie88)
Yes you are right there are three slots, two are alike the third is not . It is that one slot that the opti has to have the cam pin engage to. I had one car where the machinist installed the cam, thought the cam pin was too long and cut it off!!! The opti was not keyed in place and was indexing on the three cam sprocket bolts. It ran but it ran like crap!
Thread Starter
Drifting
Joined: May 2002
Posts: 1,530
Likes: 1
From: Houston TX
Re: Need Help - Possible Misaligned Opti Spark? (tjwong)
Thanks for the confirmation, I'm pretty sure I got it right. When I put in the Opti, it did seat okay. So if that is good, anyone got any suggestions on the problem? I never removed the timing chain, so it cannot be a crank/cam misalignment.
Racer
Joined: Sep 2002
Posts: 317
Likes: 1
From: Maple Valley WA
Re: Need Help - Possible Misaligned Opti Spark? (aggie88)
Plug wires not seated/routed properly, or worn and broken with movement around replacing opti?
I replaced one once with a rebuilt unit from NAPA. BAAAAD idea. The bearing/bushing was shot and it never ran. Shouldn't be the problem with yours though if you got it new from the general.
GL,
Jay
I replaced one once with a rebuilt unit from NAPA. BAAAAD idea. The bearing/bushing was shot and it never ran. Shouldn't be the problem with yours though if you got it new from the general.
GL,
Jay
Pro
Joined: Jan 2004
Posts: 626
Likes: 2
From: Nashville
Re: Need Help - Possible Misaligned Opti Spark? (STL94LT1)
The plug wires click twice in the opti. Check wires and sensors. I had to do mine twice it is a lot easier the second time. Did you replace the wires also? One of the connectors could have pulled loose. I didn't put anti-freeze in until it cranked ok won't hurt it for a few seconds. :cheers:
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Need Help - Possible Misaligned Opti Spark? (aggie88)
You can force the opti on incorrectly. The drive pin in the cam will fit the other holes if you try hard enough. I believe though that this would put it so far out of time that it wouldn't even run. Double check the plug wires, speicifally 5 & 7. They are right after each other in firing order, if they are swapped the car will still run, just poorly.
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Thread Starter
Drifting
Joined: May 2002
Posts: 1,530
Likes: 1
From: Houston TX
Re: Need Help - Possible Misaligned Opti Spark? (Nathan Plemons)
Thanks everyone for the tips. It turns out I did have the Opti in wrong. That thing is really picky about getting seated right. But after closing it up, I still have the misfire problem I thought would be fixed. It is not noticeable under no load, but when driving, the car really stumbles and misses. Should I go after the coil and module next???
Melting Slicks
Joined: Apr 2000
Posts: 3,198
Likes: 2
From: Northern CA
Re: Need Help - Possible Misaligned Opti Spark? (aggie88)
For anyone else reading, the opti needs to be *completely* flush against the timing cover. A 1/4" gap means the dowel pin is not seated correctly. Sounds like you found that out.
How many miles? Next I would try swapping the coil and maybe the ICM as well.
How many miles? Next I would try swapping the coil and maybe the ICM as well.
Thread Starter
Drifting
Joined: May 2002
Posts: 1,530
Likes: 1
From: Houston TX
Re: Need Help - Possible Misaligned Opti Spark? (JasonL)
Yes, the first time, I thought I got it right, there was about a 1/4" gap - but the bolts woudl easily close the gap. When it is "right" there is no question, no gap at all. It is a 46k mile car. I I changed plugs and wires and they all look good. Do you mean the ECM?
For anyone else reading, the opti needs to be *completely* flush against the timing cover. A 1/4" gap means the dowel pin is not seated correctly. Sounds like you found that out.
How many miles? Next I would try swapping the coil and maybe the ICM as well.
How many miles? Next I would try swapping the coil and maybe the ICM as well.
Melting Slicks
Joined: Apr 2000
Posts: 3,198
Likes: 2
From: Northern CA
Re: Need Help - Possible Misaligned Opti Spark? (aggie88)
Hmm 46k is a bit early for a coil to go bad, but don't rule it out. It's only $20.
ICM is the ignition coil module, which is mounted just above the coil.
ICM is the ignition coil module, which is mounted just above the coil.
