Optispark distributor

[Lucabrazzi1]

This is my first ever forum so bear with me. I have a 1994 Roadmaster Estate Wagon with the LT1 engine. Real garage kept gem from my neighbor. Total enjoyment for 18 months. Until this May. My mechanic had to replace my optispark. He put two aftermarket ones and he still can't get a spark to cylinder #3. He replaced the ignition coil and the ignition module still not luck. He ran a diagnostic on his computer and the OBD I is fine. He tried to get an OEM Optispark but can't find one. Any ideas on where to get a quality replacement or an original? Or any ideas on why one cylinder is not getting the spark?
Thanks

 

[2007LucerneCXL]

Hopefully someone this forum will respond with additional information, but there are a few LT1 related forums also check out the Chevrolet forums as they may have more information on this motor. Good luck on getting the problem corrected.

 

[Lucabrazzi1]

Hopefully someone this forum will respond with additional information, but there are a few LT1 related forums also check out the Chevrolet forums as they may have more information on this motor. Good luck on getting the problem corrected.

Thank You

 

[HotZ28]

The Optispark failure is often misdiagnosed and could be the result of ignition wire failure, spark plugs, or many other problems. I have owned many Optispark cars (Corvette, Z-28's & RMS) some vented and not. I see no mention of whether the plugs/wires were replaced during that Opti replacement? If an Opti/wires actually fail to deliver spark, the plugs will foul and not fire. Inspection of the wires & plugs should lead to the conclusion of this mystery.

 

[Lucabrazzi1]

Thank you for your help. The plugs and wires were all replaced a year ago but I will ask if he checked the wires

 

[kiltedscotsman]

MSD ignition make an over engineered (as a result great quality) one. Or they did last time I checked. Mucho $$$ though... They seem to have been bought by Holley?

OEM GM ones are readily available, AC Delco here https://www.rockauto.com/en/moreinfo.php?pk=9479292&cc=1022218&jsn=426

MSD here: MSD 83811 GM LT1 5.7L Distributor Late Model, 94-97

 

[Lucabrazzi1]

MSD ignition make an over engineered (as a result great quality) one. Or they did last time I checked. Mucho $$$ though... They seem to have been bought by Holley?

OEM GM ones are readily available, AC Delco here https://www.rockauto.com/en/moreinfo.php?pk=9479292&cc=1022218&jsn=426

MSD here: MSD 83811 GM LT1 5.7L Distributor Late Model, 94-97

 

[Lucabrazzi1]

Thank You. Another new distributor and an AC Delco ignition coil. Starts and runs great. But...when it gets hot it starts to hesitate when he puts a load on it like going up a hill. He also changed the plugs and wires. At least all 8 cylinders are firing.

 

[kiltedscotsman]

Thank You. Another new distributor and an AC Delco ignition coil. Starts and runs great. But...when it gets hot it starts to hesitate when he puts a load on it like going up a hill. He also changed the plugs and wires. At least all 8 cylinders are firing.

Mine used to be like that in top gear at 55mph/90Kph Turned out to be a vacuum leak, and new injectors. Runs like a top now. Has a good code reader been used on it whilst driving it to reproduce the problem real time?

 

[Lucabrazzi1]

Mine used to be like that in top gear at 55mph/90Kph Turned out to be a vacuum leak, and new injectors. Runs like a top now. Has a good code reader been used on it whilst driving it to reproduce the problem real time?

Thank you I will share your ideas with my mechanic

 

[2Blue]

Probably very late to the thread although I might have a little input (although you might have solved the problem by now.) First regarding the hesitation, I have a 95 with the LT1 (Three now actually, it's like an addiction). Anyway, I just went through Opti fun with mine. I had a severe misfire and stutter and just assumed after plugs and wires it might be the Opti, and if not then heck got a new opti anyway. I put on a new opti from NAPA Amazon.com: Cardone Select 84-1832 New Ignition Distributor: Automotive. Well, lets just say it was DOA. Tried again with a Opti from Rock Auto that was said to be an AC DELCO reman. (Though I dont believe they reman them anymore anyway) . Put it on and 3000 Miles later no problems, much better power. Even read some reviews of people who've tore them apart and found the genuine Mitsubishi sensors. Although I was very upset when this still didn't fix all of the miss or hesitation. I looked a little deeper and found a HUGE hole in a Vacuum line going from EVAP valve to the manifold. Long story short, I can echo what others have said about vacuum leaks and misses. Just my 2 cents, and if you have any more problems with your Opti know that the Rock Auto Delco seems to be a sturdy unit. Hopefully you've found the problem by now, I know these Optis can be a pain.

 

[G-616485]

Probably very late to the thread although I might have a little input (although you might have solved the problem by now.) First regarding the hesitation, I have a 95 with the LT1 (Three now actually, it's like an addiction). Anyway, I just went through Opti fun with mine. I had a severe misfire and stutter and just assumed after plugs and wires it might be the Opti, and if not then heck got a new opti anyway. I put on a new opti from NAPA Amazon.com: Cardone Select 84-1832 New Ignition Distributor: Automotive. Well, lets just say it was DOA. Tried again with a Opti from Rock Auto that was said to be an AC DELCO reman. (Though I dont believe they reman them anymore anyway) . Put it on and 3000 Miles later no problems, much better power. Even read some reviews of people who've tore them apart and found the genuine Mitsubishi sensors. Although I was very upset when this still didn't fix all of the miss or hesitation. I looked a little deeper and found a HUGE hole in a Vacuum line going from EVAP valve to the manifold. Long story short, I can echo what others have said about vacuum leaks and misses. Just my 2 cents, and if you have any more problems with your Opti know that the Rock Auto Delco seems to be a sturdy unit. Hopefully you've found the problem by now, I know these Optis can be a pain.

Thanks for your input. I actually just got it back 2 weeks ago. 5 opti’s later it’s running great so far. I will check that vacuum line for any potential leaks. Thanks

 

[2Blue]

Hey guys just for the record .... what i said about the Delco Opti from rock auto.... yeah I jinxed it. Seal went bad and now code 36. No oil leaks. Pretty pissed it went out in about 4000 miles. Maybe not everyone will have the same problem with it but after all the fun I’ve had I wouldn’t give one to anyone I cared for. Tried 2 Optis since, and Cardone had right bank misfire out of box (second bad Cardone right out of box, reason I got a Delco the first time.) Tried cheapie from Amazon for the heck of it, and the pin DIDNT EVEN FIT into the cam. Trying the Accel next. We’ll see how that goes....

 

[G-275757]

Hey guys just for the record .... what i said about the Delco Opti from rock auto.... yeah I jinxed it. Seal went bad and now code 36. No oil leaks. Pretty pissed it went out in about 4000 miles. Maybe not everyone will have the same problem with it but after all the fun I’ve had I wouldn’t give one to anyone I cared for. Tried 2 Optis since, and Cardone had right bank misfire out of box (second bad Cardone right out of box, reason I got a Delco the first time.) Tried cheapie from Amazon for the heck of it, and the pin DIDNT EVEN FIT into the cam. Trying the Accel next. We’ll see how that goes....

How did this go?