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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5300
Experience:  Owner at DJ Wilson
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Need help: 02 ISC Cummins runs rough with loud detonation

Customer Question

Need help: 02 ISC Cummins runs rough with loud detonation knock only when outside air is in 60's or less, feels like a strong miss pulls poorly has an 1/2 to 3/4 MPG drop-off. Replaced fuel flow, fuel timing. and fuel cutoff actuators, ran better but did not clear problem. There is no smoke out stack. Cylinder performance test showed #2 weak after local mechanic gave up, took it to Cummins, in their warm shop found no miss but said #4 and #5 low preforming but #2 was good. Picked up truck, next morning in the 50's back to rough and loud. Ambient air temperature is key.
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 1 year ago.

Hi my name is***** will be glad to try to help. Please post what you are getting for fault codes logged in the ECM memory.

Expert:  Daniel Wilson replied 1 year ago.

Hi Jim, Did you get this resolved or still need help?

Customer: replied 1 year ago.
No fault codes, no check engine lights.
Expert:  Daniel Wilson replied 1 year ago.

Thanks for the info. Sounds like an injector problem. They will need to do a cutout test but cut out all injectors but the cylinder you are testing. The engine should stumble before stalling. If it stalls instantly that injector is bad. This is the accurate way to test them. Also if they have 500,000 or more they should all be changed per Cummins. Run the overhead adjustments as well to be sure they are in specs. Let me know

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