Running erratic @ idle

[GSaltzman]

My 03 HO is sometimes running erratic while idling. The only two times it has happened was when we were picking up hay and the truck was left to pick up some bales and stack on the trailer. The truck was not sitting there idling for long. Maybe a few minutes. It sounds like the engine is hunting for a correct rpm. There is no knocking in the engine that I can hear. Once you get back in if you give it a little throttle then back off it's ok. If you don't do this it will want to stall and then it will overcompensate and launch. It does not do this all the time. The engine is stock and otherwise runs great. Advice please!

 

[OT-OF-HERE!!]

rough idle

Have you noticed any white smoke at start up? When my injectors went south I had rough idle and white smoke just at start up and when I'd idle out of the subdivision in gear it would have a rough sounding idle. Also let your truck sit for a couple days and start it up and see if you have a great deal more white smoke.

 

[Lonestar]

Sounds like your fuel Actuator Valve could be going out. What happens is they will stick momentarily in a certain position which causes the near stall, then when it frees up, the computer tries to bring revs back to normal quickly so you get the upward surge. I had this happening occassionaly on my truck, and an actuator valve cleared it right up.



KEEP ON TRUCKIN'

Lonestar

 

[rbattelle]

and an actuator valve cleared it right up.

You replaced the actuator independent of the CP-3?



-Ryan

 

[GSaltzman]

No smoke

There is no white smoke during start up that I can see. It does not run rough at all other than the two times it has done this.

 

[JStieger]

You replaced the actuator independent of the CP-3?



-Ryan

Ryan-



IIRC Tomeygun or someone posted about a month ago that the FCA was now now available through DC. A p/n was also given.

 

[Tomeygun]

Ryan-



IIRC Tomeygun or someone posted about a month ago that the FCA was now now available through DC. A p/n was also given.

Correct, FCA (fuel control actuator) is now a seperate part you can buy...

Heck, there is even a TSB about it - So even DC knows some of them are not right



https://www.turbodieselregister.com/forums/showthread.php?t=119220&page=3&pp=15

 

[rbattelle]

Missed that one. Thanks!



On edit: missed it because of the title. I tend to not read the ones about fueling boxes.



-Ryan

 

[SSkinner]

GSaltzman

Lonestar and Tomeygun are on the right track. Injectors will cause rough idle but not idle surge. The fcv is what regulates fuel deliver and inconstant fuel pressure delivery will cause idle surge. If the problem is inconstant it maybe harder to prove but fcv is more like it.