LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Help, swapped dying optispark now car doesn't run.

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Old 10-22-2003, 02:14 PM
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Default Help, swapped dying optispark now car doesn't run.

Ok my girlfriends opti on her '94 z28 recently crapped out. I got a rebuilt one from Autozone and swapped it in. Now whenever I try to crank it over it just won't catch. It will barely fire a few times and will only stay running (and I use the term running loosely) for a few seconds. I haven't had much of a chance to look at the car since then but I need to know what I should be looking for. I'd assume the timing is just drastically off but what would cause that and how could I fix it?

A list of possible problems and ways I could try to test/diagnose them would be very helpful. I don't want to tear the thing back down for nothing yet. Any suggestions? BTW: to take care of the most obvious answer: Yes the sparkplug wires are all in the right place. Thanks!
Old 10-22-2003, 02:31 PM
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Default Re: Help, swapped dying optispark now car doesn't run.

Gangly, where are you...?
Old 10-22-2003, 02:42 PM
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Default Re: Help, swapped dying optispark now car doesn't run.

Ok my girlfriends opti on her '94 z28 recently crapped out. I got a rebuilt one from Autozone and swapped it in. Now whenever I try to crank it over it just won't catch. It will barely fire a few times and will only stay running (and I use the term running loosely) for a few seconds. I haven't had much of a chance to look at the car since then but I need to know what I should be looking for. I'd assume the timing is just drastically off but what would cause that and how could I fix it?

A list of possible problems and ways I could try to test/diagnose them would be very helpful. I don't want to tear the thing back down for nothing yet. Any suggestions? BTW: to take care of the most obvious answer: Yes the sparkplug wires are all in the right place. Thanks!
First off, buying a unit from AZ was the beginning of your problems Those rebuilt units are pure crap and just the optical portion proves to be a crap shoot when trying to purchase those rebuild kits from them. They cost as much for a reason. I know you don't want to tear it down again, but I would source a new complete unit from the dealer so you will avoid chasing your tail and spending frivoulous cash on everything but the real problem solver. I've been down the same road your on and I ended up basically rebuilding a motor in the driveway because I replaced darn near everything but a piston before I put in a working opti-spark which fired the car right up.
Old 10-22-2003, 02:59 PM
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Default Re: Help, swapped dying optispark now car doesn't run.

buy a new opti and be done with it, I tried to go autozone as well and found they do not sell the complete opti like GM does and ran around like an idiot for the longest time, bought an new one shipped second day for 318.00 and was wiping my hands clean of the mess. Return the autozone unit and buy the entire thing.
Old 10-22-2003, 04:26 PM
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Default Re: Help, swapped dying optispark now car doesn't run.

Damn.. I was REALLY hoping not to hear that. Is there any possible way I can test what's in there to make sure that's the problem? Money is VERY tight right now so we don't want to spend the extra money on a dealer bought opti if that's not even what's causing the problem... any other suggestions?

Oh and I'm in Lido beach Mario.. South shore, Nassau county, why?
Old 10-22-2003, 08:08 PM
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Default Re: Help, swapped dying optispark now car doesn't run.

the autozone parts are cheaper for a reason, one thing ive definately learned over the years is that price is a good indicator of quality asa far as sensors and computer controlled components
Old 10-23-2003, 02:40 AM
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Default Re: Help, swapped dying optispark now car doesn't run.

Scrap the autozone rebuilt unit. Big Show is correct(as always) and replace it with a GM one. Optisparks arent fun to trouble shoot and in my opinion its definately worth it to put a completely new unit on just to keep from worrying about when the rebuilt one will go out...a friend went through about 4 rebuilt opti's in a little under 2 years, replaced it with a factory unit and hasnt had a hiccup since.
Old 11-07-2003, 12:37 PM
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It's too late now but I got my opti-crap from az also. My car would start but not act like it was actually running??? It's hard to explain but with my pedal to the floor it was barely running. I looked further into opti-crap history and found a website, mike chaneys dissection, On that website he had the small round metal disc under the larger metal, the larger disc has the 360 slots. On the opti I bought it had them reversed. I took everything apart and reassembled it according to mike's dissect. My car still will not start. It is backfiring out of the throttle body now. Have you fix your girlfriends yet?? What did you do if you have?? I'm taking my opti off again today.
Old 11-07-2003, 02:46 PM
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What I normally do is pull the wire to the opti and hold it next to a header while someone cranks the car - if you have spark there you know you are getting a power to the opti - then plug it back in and pick a spark plug wire and do the same thing.

If you have spark to the opti and nothing out then it's the rotor/cap portion for sure. If you have no spark going into the opti then I would get the ingnition module checked, then try swapping on a new coil.

If the optical encoder is bad there isn't a good way to check it out without a scope - you pretty much need to swap in a new opti. The autozone unit has a lifetime warranty I believe, so you might just swap it out.
Old 11-09-2003, 06:41 PM
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Contact Dal Slabaugh:

lockitup@bright.net

He quoted me $198.24 + shipping which was supposed to be around $6.00...for a brand new Opti...he's cheaper than Jason Cromer...
Old 11-10-2003, 02:24 AM
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I had a problem similar to that when i put my opti back on after a cam install. You might wanna check that the little shaft from the timing gear to the opti is in the right way. Mine had been forced on by the previous owner and went in two different ways. if its not in right it will sound like like you have a few crossed wires and will idle real low, then stall and cut off.
-Larry
Old 01-21-2011, 01:28 PM
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Ok so i know this is an old thread but i ran into the exact same problem. The little shaft of a 92-94 style had a little rust on it because it was in the wet distributor. The keyed part of the shaft allowed me to stick it in the distributor any way! So if anyone tells you it is completely keyed in, that may not be the case. You just really have to pay attention and look at the double key marks in the block and on the distributor to make sure that shaft is in there right!
Old 01-21-2011, 05:12 PM
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Default Opti

Did you check if piston #1 was up before installing the opti?
Old 01-21-2011, 08:01 PM
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Again old post...but the #1 piston dont have to be up on a compression stroke,as long as the OP did not rotate the motor,there are splines on the cam gear,as well as the splined opti shaft.make sure they line up and install the opti.do not force it.



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