Dropping cylinders at idle
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Dropping cylinders at idle LM7 swap in 94 Camaro z28. Was running poorly so replaced spark plugs and coils. Seemed ok but then wouldn’t start, so replaced fuel pump with a DW200 255lph. Starts up fine now but within 10-15 sec of idling it starts misfiring and sounds like it’s dropping cylinders. It has MostPlus 60lb cheap injectors, so that’s a thought or maybe idle control module. I don’t know how it’s tuned so I’m afraid to swap injectors yet. Also A/F ratio all over the place. Any ideas?
Last edited by vvangrod; Nov 11, 2022 at 07:30 PM.
Thread Starter
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Joined: Nov 2022
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What is PCM that you are using in Camaro ? Factory
What is static fuel pressure ? No mechanical gauge, but should be 58psi with corvette style return filter/fuel pressure regulator
What fuel pressure at idle ? See above
Can you approximate camshaft duration figure ? I don’t know but sounds stock, possibly ls7 or similar mild cam
Where did you obtain Injector data ? No access to tune yet so idk what data was input for injectors
What is static fuel pressure ? No mechanical gauge, but should be 58psi with corvette style return filter/fuel pressure regulator
What fuel pressure at idle ? See above
Can you approximate camshaft duration figure ? I don’t know but sounds stock, possibly ls7 or similar mild cam
Where did you obtain Injector data ? No access to tune yet so idk what data was input for injectors
Tune. The injectors your using require a very specific tuning window…as does every other injector. The injectors must be flowed to figure their requirements, then the data is analyzed and converted into the VE (fuel flow) in the ECM with HP Tuners or similiar. If untuned, your ECM still has the fueling for the factory injectors in the VE tables. Lots of variables are involved here to get the tune right. If you’ve had the car tuned, disregard everything I’ve said here…
