Rough idle...injector failure symptoms?

[BHolm]

Just recently my '05 truck started to idle roughly, like it is missing on a cylinder or two. This morning it was pretty rough with black smoke for a few seconds. It was cold out but nothing out of the ordinary. The truck has started better many times in similar weather.



I am running Redline fuel additive. The first tank with it was a whole bottle in a full tank. This was the second tank and I started with a half a bottle. It ran fine through the first tank and started running badly on the second tank. I added the rest of the bottle and drained the water trap in the fuel filter just in case. The truck is still under 5,000 miles.



If I idle it up to 1100 rpm it runs fine. It runs just fine on the road too and has plenty of power. The only thing that has changed is the idle, it shakes the truck.



I am pretty convinced that I have at least one leaking injector. If I drop it off high idle it takes a few seconds then starts missing. I think what is happening is that fuel is leaking un-metered through one or more injectors causing the rough running.



I ran it fairly hard today in an attempt to use up this tank of fuel. It would be nice to rule that out for sure. I pulled my snowmobile trailer over the pass and ran the truck fairly hard. Not much wieght but definately some work due to the grade and my heavy foot :-laf For the first time I could smell the truck when I got home. You know, the paint burning off the manifolds smell. I wonder if the offending injector/s are running up my EGTs as well?



Anyway, just my rambling thoughts. I know I am going to end up at the dealer, the truck is almost brand new. I just thought I would throw this info out there to see if anybody had any thoughts confirming or denying my theory.

 

[tschwab]

Keep us posted, I am particulary intrested due to the fact that you are using Redline, which I was going to switch to from Stanadyne Performance Formula. Now this is a long shot... . but were you using some other fuel additive before Redline? Stanadyne is a Demulsifyer which pools the water into larger clups hopefully to be caught by the water/fuel seperator, where as Redline is an Emulsifyer which disperses water into very small droplets into the fuel which supposedly should pass through the fuel system with no harm. Is it possible that the Redline could have not safely passed the water through and this is playing havoc with your fuel injection system? I hope this is not the case, but could be a longshot possibility?

 

[jelag]

I had the same issue with my 04 and after 2 weeks at the dealer it turned out to be lift pump failure... . in that it wouldn't provide the volumn needed by the cp3 pump... the injection pump failed and the failed parts in the pump created the rough idle... .



Dealer replaced both these parts and several others while they chased the problem under warranty... .



They tell me my 05 however now has the lift pump in the tank instead of at the engine...



Jim

 

[BHolm]

I was not using any other additive prior to the Redline. The truck ran great on the first tank, a good 300+ miles.



It really seems like too much fuel is the problem. If there was a bad fuel problem, either just bad fuel or because of the Redline, that I would notice it more than just at idle.