Need some suggestions - struggling with EFI tune

dversaw

Member
Hi CACC Braintrust,

I've been struggling getting my Cobra tuned. It shouldn't be all that difficult with the system I have, but I'm stumped. Tried everything I can think of. It's been running great for years, but after sitting for a while during Covid, forgetting to plug it in and running the battery down to nothing (losing EFI computer settings), I can't get the idle anywhere close to a decent level when running a new tune. As soon as the engine warms up, the idle sways all over the place, down to almost nothing, where it stalls out. Now it is starting to backfire, so the mixture seems off. My first thought was old gas, but I've diluted the old gas (which there wasn't much) with new high octane. So I don't think that is it. O2 sensor seems to be working normally.

The simplified setup:
351W with a FAST EZ-EFI.

Does anyone have experience with this type of setup that would be willing to help me troubleshoot ideas?
 

Rob Burton

Contributing Member
Member
I think it is still in the learning process. Drive it for a bit and see how int acts after that.
 

kellerscobra

Contributing Member
Member
I have used Brake Kleen and sprayed that around the intake area. If that gets sucked in, you can hear the idle change.
 

Tom Wells

Contributing Member
Member
Also exhaust leak if the O2 sensor is near the sidepipe joint. If it is leaking typically it will make the car run pig-rich.
 

Mike Holt

Member
I recently had a similar issue. Had to recalibrate the O2 sensors.

I have the Pro-M set up tho. Not sure how the EZ-EFI works.
 

Danbo

FFR6198 Dan Deitz
Contributing Member
It’s sounds like the fuel propto-energizer reciprocating idle driven transponder!
 
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