LT1 misfire and popping (Page 2/2)
Will APR 27, 07:40 AM

quote
Originally posted by str8maxn:

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.
Will APR 27, 07:58 AM

quote
Originally posted by cyrus88:

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.
str8maxn APR 28, 05:18 PM
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?

Or are you using another method?
thejinx13 APR 28, 07:06 PM
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).]