Optispark distributer is the usual culprit. MY optispart had oil in it and I had to take it apart and clean it to clear misfires.
I had the exact same issue as this, the crank hub seal was leaking, water pump drive seal and the Optispark seal was crumbling. Cleaned the Optispark carefully, replaced those three seals.. got less then 1200 miles and the Optispark failed.
Decided to either do a full LS engine swap or what Will suggested. Since my engine was already built for boost I opted to convert the ignition, used an expensive but high quality kit from Torqhead.com
CYRUS88 >>> The LT1 is out of a 93 Vette. How hard it to replace the optispark on a scale of 1 to 10. Ten being the hardest?
WILL>>> Wow, I didn't know LS Coil conversion was possible.
Waterpump has to come off for opti-spark maintenance, so it's an extreme PITA in a Fiero.
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Originally posted by InTheLead:
I had the exact same issue as this, the crank hub seal was leaking, water pump drive seal and the Optispark seal was crumbling. Cleaned the Optispark carefully, replaced those three seals.. got less then 1200 miles and the Optispark failed.
Decided to either do a full LS engine swap or what Will suggested. Since my engine was already built for boost I opted to convert the ignition, used an expensive but high quality kit from Torqhead.com
Let me start off by saying I am not a mechanic; so if I sound like a dumbass please forgive me... I recall the last owner replaced the OptiSpark with an MSD vented version. I do have a small pickup air line coming from the air intake filter. and have paper work for the MSD unit.
How prone are the MSD Opispark to failure? Is there a way to test the MSD Optispark?
In another site, Someone had the same problem and it turned out to be the ICM. Could this be the problem? How can I test the ICM?
Going back to my original question, do you think a sticky or a clogged injector could be the cause. I remember the last owner saying that the car was running great until it was not. A few years later, while talking to his father in law; who's car left him stranded because hose line that was used inside his gas tank that had turned into playdoh didn't allow fuel to be picked up.
As it turned out, he did the same when he ran the stock fuel pump for the vette inside the fiero tank.
Consistent or intermittent misfire? Idle or only loaded?
There are a number of troubleshooting techniques to find a misfire... Unplug the injectors or spark plugs one at a time, for example.
On cold starts it idles fine for the first 3-5 minutes. After which I start to hear the popping coming from the exhaust. The popping is also present during normal driving.
Thanks.. Looking forward to your input.
[This message has been edited by str8maxn (edited 04-26-2021).]
Originally posted by str8maxn: CYRUS88 >>> The LT1 is out of a 93 Vette. How hard it to replace the optispark. . .
It's fairly simple, just tedious. I can't put it on a scale because I don't know your skill/knowledge level. For me it was about a 1.
If you have an LT-1 water pump, then it's more involved because you have to drain coolant, remove and reinstall pump, etc. I have a remote electric water pump, so I didn't have to touch the cooling system. I did have to tilt the rear of the cradle down to get the balancer and optispark out, though.
Be careful about the MSD opti, the rotor can fall apart inside (do a google search).
On cold starts it idles fine for the first 3-5 minutes. After which I start to hear the popping coming from the exhaust. The popping is also present during normal driving.
Thanks.. Looking forward to your input.
Basically, if you can't narrow the misfire to one cylinder, then it's the opti-spark. Google and YouTube should have lots of misfire detection techniques. Start with the basics: -Inspect plug wires -Pull and inspect spark plugs -Use an inductive timing light on each plug wire successively to get a visual gauge of whether the spark is intermittent. Also check timing via the timing light to see if the spark is moving around. -Unplug each injector successively to see if the miss goes from an intermittent to a dead miss on one particular cylinder
WRITE EVERYTHING DOWN. If you think it sounds tedious reading it here, imaging doing it twice because you didn't know for sure what you did the first time.
If you have an LT-1 water pump, then it's more involved because you have to drain coolant, remove and reinstall pump, etc. I have a remote electric water pump, so I didn't have to touch the cooling system. I did have to tilt the rear of the cradle down to get the balancer and optispark out, though.
Be careful about the MSD opti, the rotor can fall apart inside (do a google search).
I've never worked on an LT1 Fiero, but I can't imagine access for waterpump removal NOT being a nightmare.
For the guys that have an LT1 are you able to use the ODB1 port to find trouble codes via a paperclip? If so how? What pins? Using the stock fiero check engine light?
The optispark on my Camaro failed twice, exact symptoms you are having . Mounting the most sensitive timing mechanism ever invented under the water pump makes my brain hurt. That being said, I did get a random multi misfire code from my ignition module one time too.
But, my money is on the Opti. Visit any Camaro board and search optispark and you'll see.
[This message has been edited by thejinx13 (edited 04-28-2021).]
