Rattle with RP Fluctuation

[Erik@LCD]

Looking for some help here, this is one we haven't seen before.

Have an 04. 5 manual truck that has a cyclic rattle at idle. Every 7 seconds or so, it has what sounds like an injector or lifter rattle. Hooked up to the scan tool, this sound corresponds to a change from 5500psi (ish. . normal idle pressure) to a spike of 10-13kpsi. I suspect the noise is the injectors rattling or a return valve rattling. The cause is the question.



I am leaning to the FCA as the cause. Any thoughts or similar experiences?



Thanks!

 

[p-Bar]

Eric,

A bad FCA will usually cause a rough idle, they will leak also. From what I have read if you shake it and it rattles it's OK . This what I have gotten from TDR Forum.

 

[SierraRam]

Looking for some help here, this is one we haven't seen before.

Have an 04. 5 manual truck that has a cyclic rattle at idle. Every 7 seconds or so, it has what sounds like an injector or lifter rattle. Hooked up to the scan tool, this sound corresponds to a change from 5500psi (ish. . normal idle pressure) to a spike of 10-13kpsi. I suspect the noise is the injectors rattling or a return valve rattling. The cause is the question.



I am leaning to the FCA as the cause. Any thoughts or similar experiences?



Thanks!

My FCA failing caused the exact same symptoms, a cyclic injector knock was the beginning followed by rough idle and stutter, rp was going wild. Changed the FCA and all was back to normal.

 

[Erik@LCD]

thanks guys, I will order one up and give it a try

 

[RDyson]

You can get that new FCA from Cummins for just under $100. They cost alot more from the dealer.



Randy

 

[JJPage]

Cummins part #4932457 ACTUATOR FUEL CONTROL, It may also be a bad rail pressure sensor, and the ecm is trying to compensate. The rail pressure sensor is less money than the FCA.