idle question

[TWhetten]

Just got a 3rd gen, and love it. However I am having trouble with the idle, I think. After the truck warms up if I bump the throttle the rpms will go up to 1100 and stay there. The only way I have found to bring the rpms back down is to turn on the pacbrake and lug the engine down or put in gear and ease off the clutch until the rpms go back down, then put back in nuetral. Is this normal? I wish it would do it when it is cold, so the truck will warm up faster, but it won't.

 

[p-Bar]

Very unnormal take it in to the dealer

 

[Slow Six]

I have the same problem and have had it in a couple of times. They put in some expensive conditioner as they seemed to think it may be a dirty injector. This did not improve things. I had the CP3 replaced and the high idle is occurring less but is still not right. The Xzilleraider seemed to provoke the idling but even with it completely removed the condition still exists. I am hoping that the next time in they will decide to check injectors and possibly replace. I will report results but it may be a while as I am busy and need to get it in during a break. Let us know if you find out anything.

 

[TWhetten]

I have ran a bottle of Lucas upper cylinder lube through it and it seems to have fixed it. I can't get it to stay at a high idle anymore.

 

[Slow Six]

Had mine into the dealer yesterday and still have the idle problem. The technician is looking for help from their tech line. He says that if it is a bad injector it may be a long process to find it. My idle problem is some what intermittent and is worse once the engine is warmed up.

 

[cerberusiam]

Actually it is perfectly normal for the 3rd gen trucks to idle up like this. Its a safety feature built into the ECU that senses intake air temp and idle condition then idles the engine up to keep things warm and prevent washing the cylinders down with uncombusted fuel. My 05 will do it warm or cold if the air temp is low enough but it will drop right back if I touch the brake then idle back up after a couple of minutes.



The idle that won't drop back is something the manuals have a problem with and may be related to the hard start problem with synch of the crank and cam position sensors. Injectors could cause it but you should be seeing a lot of white smoke on start up and declining mpg along with it. It could also be an IAT sensor that is going bad and demanding the ECU idle up.



This may not apply to the early 3rd gen trucks as I am not sure when the auto high idle was implemented, but its something to investigate if nothing else works.

 

[Slow Six]

Our problem is not the high idle. My truck is an early 03 and the high idle for cold works okay. The situation I am getting is the idle speed stays at around 1000 when I push in the clutch to stop or if I hold the go pedal at any rpm over the 1000 mark the engine will not slow down to the 800 rpm. A bump on the Jake or just slightly let the clutch out in gear and it will drop down. When it sticks at the 1000 mark the speed is not always constant and the situation is worse once the engine is warmed up.

 

[cerberusiam]

Our problem is not the high idle. My truck is an early 03 and the high idle for cold works okay. The situation I am getting is the idle speed stays at around 1000 when I push in the clutch to stop or if I hold the go pedal at any rpm over the 1000 mark the engine will not slow down to the 800 rpm. A bump on the Jake or just slightly let the clutch out in gear and it will drop down. When it sticks at the 1000 mark the speed is not always constant and the situation is worse once the engine is warmed up.

Thats why I mentioned the IAT sensor as a potential source of the problem. If its holding at around 1000 rpm's its seems the high idle has been activated for what ever reason. This could be due to a number of reasons and can happen when the engine is warm or cold. The IAT sensor getting dirty has been a source of problems since the 24V's came out and now that everything is run thru the ECU its readings seem to be even more critical.



There have been a couple of threads on this in the past. You might try a search and see what you find. I don't remember if a absolute cause and solution was ever found but it seems the manuals were more prone to this problem.

 

[JHardwick]

I've got the same problem with my early '03. The cold weather high idle seems to work fine. But, right now with temps in the 60's to 80's it'll idle up to 1100, not 1000 and injector rattle like crazy ... ... ... ... it's different than the cold weather high idle, trust me.



As a matter of fact, I dropped a horse off in Columbus, Ind a couple of weeks ago to a lady who works at Cummins. As soon as I stepped out of the truck, she said "that's not right". :{