Poor idle quality when cold?

[231jasonS]

So I've noticed after I installed the DDP90's that I have a lopy/rough idle when cold.



It usually smooths out pretty well when it gets up and going.



It isn't cold here just in the 50's. It is there even when I turn the Edge off or change levels. Ive checked the oil and no real sign of fuel. I suspect a FCA but what else could it be. Truck has 32K on it. It goes away when I raise the rpm's. its only there below say 750-800. It hazes pretty well at idle and at low boost, but once it builds boost it cleans up pretty well. (probably due to CP3 not being able to keep up)



A rail relief valve would do this? It was wet when i came apart to do the injectors, but had no symptoms prior to that. I had never run a pressure box to blow this valve.

 

[HOBrian]

Mine lopes at idle when cold, is yours a lope? kinda like a gasser with a cam in it.

 

[231jasonS]

Yes exactly... ..... why does it do this?

 

[HOBrian]

You might want to sit down first...



Sitting down?



Steved had the samething happen to his before his injectors needed a rebiuld! Mine only do it if I don't plug in. If I plug in and the let the truck go into high idle by itself she won't do it. It only happens if I don't plug in and she goes to high idle. I pray everyday I don't have to do injectors anytime soon. She runs fine and makes no oil so I still keep my fingers crossed and pray to the Bosch god everyday!:{

 

[steved]

Yeah, before I initially lost an injector, it would lope just like a gasser with a big cam when it would kick into high idle... about a month later, I lost an injector.

I almost wounder if it wasn't the weak solenoid that actually caused my troubles in the first place...

 

[HOBrian]

Jason just rereading your OP are those new injectors or just tips?? If just tips I wonder if having bigger holes in the tips makes this more noticable?? You had the problem before but could not tell because of the stock tips. Going on a complete guess so...

 

[231jasonS]

Brian, yes tips only... ... . I see your logic on the bigger hole. I have always had an occasional slight stumble at low idle (in gear). It would show up after an an extended cruise on the freeway then come to the first stop and it would be a very slight stumble (like a bad plug wire on a gasser). It would disappear as soon as i raised the RPM's a little and was never consistent.

What would be the best way to diagnosis this?

 

[HOBrian]

Best person would be Steved...



https://www.turbodieselregister.com...sions-2003-2007/186374-testing-injectors.html



https://www.turbodieselregister.com...7/193482-hah-rough-idle-cured-thanks-tdr.html



https://www.turbodieselregister.com...7/193836-need-injectors-soon-like-friday.html



https://www.turbodieselregister.com...003-2007/207400-injector-efficiency-test.html



https://www.turbodieselregister.com...09376-just-flollow-up-my-injector-issues.html



Take a look at all this, it is all about what Steve went through for his. :{:{

 

[231jasonS]

Thanks for the links. Good read. I capped the RPRV and have yet to start it cold. But it was running well with no sign of a stumble/lope. Well see how it goes.

 

[HOBrian]

Report back for sure... I hope it works!