Engine/Transmission (1998.5 - 2002) 1000 RPM Idle

[CFAR]

I was travelling down Hwy 99 from Sactown to Merced, 65-70, cruise on, got to Merced and stopped at a light and what do you know 1000rpm. Turned it off, back on, still 1000rpm. Stopped at a gas station, went inside, got some bottled water, came back outside, popped the hood, wiggled some wires, started it back up and 850rpm.



Hasn't done it since, and ran fine when it was idling high.

No codes.



Any ideas?

Anyone seen this before?







2001QC 4x4, BullyD III, comp, scottyII, other assorted and sundry items.

 

[COWBOYDUALLY]

here we go!!!

CFAR, I had the same problem Twice!!! turned out to be the throttle positioning senser, at least thats what the dealer told me, they said that they replaced it. after a couple times of high idle i lost the trottle completely, had it towed back home and started it up at the dealer to see if it came back, well it came back and had throttle again,so much for the 500 dollar tow . i was told that it was the VP44 about to kick the bucket but it wasnt and i am still on the original injection pump. take it to your friendly CUMMINS engine shop... ... Jeremy

 

[CFAR]

And here I've gotten 111,000 miles with only a couple lift pumps gone. Now a tps, its worn out I tell you!!!!!



Thanks Jeremy.



I'll try to avoid the tow.

 

[ChrisWilliams]

I had this happen to me twice on my 01 a few months ago after a couple of hours on the Interstate @ 70. I shut down the engine for 15 seconds or so and cranked it back up, went back to normal. I figured it was the TPS or a bad connection to the TPS. No problems since. If it keeps happening with regularity, try pulling the wires to the TPS and put a little dielectric grease on the contacts. It just takes a little bit of glaze/corrosion to raise the resistance which would change the output from the TPS and might bump the idle. If the TPS was bad, I would think it would act up worse, like no throttle response or a hesitation.

 

[KcoleKennyc]

Mine did this and it was the VP-44, maybe you will be lucky and it will be the APPS instead. It's much cheaper and easier to install.

 

[Hahn007]

If it keeps happening with regularity, try pulling the wires to the TPS and put a little dielectric grease on the contacts.

I have seen this a lot about using dielectric grease to improve a poor electrical connection. I was under the impression that a dielectric had insulating properties and don't understand how this would improve current flow. I would think it would aggravate the problem. Please correct me if I am wrong. Thanks.

 

[ThrottleJockey]

Chris,



Dielectric grease has a slicone base that resist corrosion and promotes metal to metal contact.



You wouldn't want to put it in your axels or anything like that.



Brian

 

[HBarlow]

CFAR,



Replace the APPS. The classic symptom is fast idle (which prevents the exhaust brake from activation if so equipped) then, ultimately, dead pedal.



I replace the APPS on my truck every 40k to 45k miles. Three of them last year! I carry a spare.



Harvey

 

[EGaskamp]

How do you replace the APPS? I was thinking that could be my problem too. I was driving a few weeks ago and I was about to shift to 3rd and the truck just fell flat on its face and died. It started right back up. No codes no nothing and I haven't had a problem since. Plus I was just ccurious on how to change it. Thanks.



Eric

 

[CFAR]

I will probably get a spare, but until the thing fails... .



I want to actually see it fail before I replace it. Its only done it once, so its a waiting game.



3 a year seems kind of high, have you taken one apart to see the failure mode?

 

[Allnew2Me]

Another place you might wish to check is the temp sensor that is mounted to the thermostat housing on the top front of the engine. If it gets unplugged or has a bad connection it will tell the ECM that the engine is cold and call for high idle. I had something like that happen and that was what it was.

 

[CFAR]

I don't have the high idle enabled.

So would it still cause high idle?

Wouldn't it throw a code if there was no connection?



That happens to be one of the connections I wiggled.

 

[Short Stack]

CFAR I am having the same thing right now, I first had no e-brake and high rpm on a trip to Reno in Dec of 04 and then never had any more problem untill I went up to Reno in Dec 05 it did the same thing again. Since then it has done it a few times, I just restart the truck and it is fine. Last saturday it was working fine and then my check lite came on, checked the code with the key and had only P1963. Went to a freinds house who has a code reader and it brought up P0121 APPS voltage something or other. He accidently cleared the code, so I checked with the dealer and they cannot do anything untill the code comes up again, so I borrowed a APPS from my freind just in case my dumps on me. We are taking the 5er out this weekend so I dont want to get stuck somewere on the road. So all of your syptoms are a bad APPS. Mine is still under warranty, good thing I here those are around 4 bills.

 

[CFAR]

I thought there was someone who would fix these, seems like they had a website also.



No ebrake? Do you have it hooked up to pin 20 on the ecm? If so then it probably is a APPS, it thinks you have your foot on the pedal all the time.



What I'd really like is a defective APPS to disect.