Truck surging running rough

[CToney]

My dad's '03 has started to surge at idle sometimes and will stumble sometimes when starting out. It has a FASS on it and had an EDGE EZ on for a while (lowest setting). Would the FCA be the problem? It throws no codes. Need some help diagnosing the problem.

 

[GaryOwen]

Could also be APPS - I've had one fail with no codes set.

 

[p-Bar]

throw some 2 stroke oil in the fuel tank . If it smooths out then it's the FCA

 

[VolCTD]

See my previous post on this:



https://www.turbodieselregister.com/forums/5-9l-engine-transmissions-2003-2007/212114-rough-idle-especially-after-towing.html

 

[Rollin' Heavy]

I can not remember, but I think it is Steved who brought up the A/C wiring right above the oil filter rubs and creates a short. It can be intermitten. I am not sure but you can at least check it out. I know there is a write up about it. I just dont remember where right now.

 

[SierraRam]

My 03 did that when the FCA started hanging up.

 

[CToney]

The FCA part number is the same on all trucks? I found a PN on another thread and the least expensive that I can find it in Canada is $200. I will check out the AC wiring. With the Canadian dollar going up I might look into one from the US.

 

[GaryOwen]

Cummins P/N for my 03 is 4932457. I think it is the same P/N for all 3Gen's. I think the price was about $120US a couple of years ago.

 

[steved]

The AC wiring rubs bare on a bolt on the rear of the AC compressor... it does cause some weirdness. I found mine worn through quite a bit of wiring insulation, with a fairly large bare spot. It caused a rougher than normal idle... the truck actually started hard initially once it was repaired (like the PCM/ECM were relearning a new parameter).

I remember reading it is a combined circuit that also serves the crank/cam sensors?

Been a while since I read that... this was a common thing in 2003/2004... and its in the archives here at TDR. I cannot take credit for discovering it, only for remembering it from way back.

Your symptoms however, sound like a failed FCA. The cycling idle are very characteristic of a failed FCA...

 

[CToney]

Thanks for the help guys. Anyone familiar with N14's I am having trouble with my throttle cutting out in my T-800.