92 base model 6 speed engine question
Thread Starter
3rd Gear
Joined: Aug 2023
Posts: 3
Likes: 0
92 base model 6 speed engine question
Hi Guys,
I've got a 92 base with 86,000 miles been well maintained. Car runs great under normal circumstances but if I jump on it between 4500 and 5000 RPM's it will start breaking up missing and back firing. I don't want to bend a push rod or hurt it worse. Any suggestions where to check first. Had a new optispark a couple years ago. Gas is good, Any thoughts obviously without any diagnostics it's tough but Just curious if anyone else may have experienced this.
I've got a 92 base with 86,000 miles been well maintained. Car runs great under normal circumstances but if I jump on it between 4500 and 5000 RPM's it will start breaking up missing and back firing. I don't want to bend a push rod or hurt it worse. Any suggestions where to check first. Had a new optispark a couple years ago. Gas is good, Any thoughts obviously without any diagnostics it's tough but Just curious if anyone else may have experienced this.
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
With not much info, my guess would be spark related. Wires, plugs… ICM (on a standoff on front of passenger side cylinder head). Or, Opti.
problems hot and cold or just hot? You should probably also put a fuel pressure gauge on the rail and tape it to the windshield so you can see it. What is fuel pressure doing under that load/rpm?
problems hot and cold or just hot? You should probably also put a fuel pressure gauge on the rail and tape it to the windshield so you can see it. What is fuel pressure doing under that load/rpm?
Thread Starter
3rd Gear
Joined: Aug 2023
Posts: 3
Likes: 0
The engine is warmed up about 198 degrees. When I get on it hard up to 4500 to 5000 RPM it breaks up and pops and spits. But runs and starts perfect otherwise. Seems like might be starved for fuel or ecm isnt set up correctly?
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
More diagnostic work is needed. Any codes? Do you have a fuel pressure test gauge?
It could still be spark related, the ICM can work fine cold and start to fail under heat soak. What does the tach do when the issue occurs?
It could still be spark related, the ICM can work fine cold and start to fail under heat soak. What does the tach do when the issue occurs?
Thread Starter
3rd Gear
Joined: Aug 2023
Posts: 3
Likes: 0
92 base engine question
I never rev the engine cold only after warming up. When I punch it hard under load up around 4500 to 5000 RPM it will start to break up missing and popping. As soon as I let off the gas it smooths right out and run fine. Otherwise it starts first hit on the ignition. Runs great. It’s only at high RPM under load.
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