Idle jumping around

[dan_gilson]

I have a '98 24V with ~55K miles on it.

Recently the idle starting jumping around.

Sometimes it is ~800RPM and other times it is

as high as 950RPM.



Has anyone run across this before and know

the cause? Thoughts and suggestions would

be greatly appreciated.



I know from previous posts that the idle

seems to be controled from the ECM. Obviously

it is getting it data from a couple of

sensors. Do I have problems with one of

more being dirty or not working correctly?



Thanks in advance!

 

[TDickerson]

Seems to me that everytime an idle issue comes up people will blame the lift pump. Had mine replaced too at about 40K miles and had alot of idle drop and then my son said the idle jumped up pretty high. He told me they replaced the pump. I'm assuming it was the lift pump. I left the truck with him to take care of so I wasn't there. I do remember just before I left it with him the truck would have a hard time in reverse with my camper and would cut out on me. The only problem I had with the engine so far.





__________________________________________________

1997 Solid Black 2500 4X4 SLT 3. 54, auto (lazy), loaded except leather (next time) fully stock with chrome westins (love em). Son taking care of it (driving the you know what out of it in Jax Fl) while I’m overseas.

 

[SWC]

TPS

With less then 5,000 kms on my new truck the motor started idling as you described. This would not happen all the time. On two occasions while driving I would have no throttle response. That finally sent a code to the ECM. The problem in my case was a faulty Throttle Position Sensor. When the motor would not respond to the throttle, I would shut down the motor, wait 10 seconds and start the motor. Then I could drive again.

I hope you get your problem solved. I know its not fun when this happens.

Stan

 

[dan_gilson]

I have a friend who just got an OBDII reader.

Maybe it time to check the ECM.

 

[dan_gilson]

I checked the truck this morning with the

OBDII probe. It says that everything is OK

but the throttle position sensor say

that I am already at 12% on idle.



I would have thought that this should be

at 0% until you push down on the accelerator

pedal. I check the linkage and it seems

OK (even a little loose).



The pump level is on the stop and seems

to have a reasonable amount of slack.

(More than my liking. )



Can anyone point me to where the

Throttle position sensor is and how to

further diagnose it?



I have an alldata account but it show

a 12v setup. It was very non-helpful.



Thanks in advance!

 

[dan_gilson]

I took it into Cummin West and they put their Checker on it which is on the other side of DC's OBDII. All tests passed.



After I paid up and drove away the engine check light came on and stayed. I brought it back to them and still all tests passed and they could not see any codes. They told me that this was not the firs time for this. Their insight checker does not look at the stuff DC's OBDII checker looks at.



I had given back my friend's OBDII checker by then and had to ask to borrow it again. By the time it got to me the Engine check light had turned off and no codes showed up on the checker.



Cummins did upgrade the ECM flash.



I can't tell you how nice it is to be serviced by a professional shop. My appt was for 10:30 and they took the truck at 10:20. They said to expect them to have it for 1. 5 hours and . 75 hours later they told me it was ready.



Any and all DC service managers should take note here. Typically when I take the truck to DC it does not even get moved back to service for a couple of hours and then they take a couple of hours more to look at it, so I have blown 4 to 6 hours just for them to tell me what is wrong. Then typically the really bad thing comes: You will have to make another appt because we do not have the parts in stock. Arrggg!!!! If this had happened only once or twice I would not be making so much of a deal about this. I got the paper work to show that this happened most of the time I bring the truck in for repair.



I anyone else has some ideas please give me a shout. I think I am in a mode now where I will just have to wait for it to get bad enough to throw a code.

 

[illflem]

Dan, as far as your alldata account, you need to enter '98. 5 or '99 to get info for the 24 valve.

 

[dan_gilson]

I think the one that I have is for the 98. 5. It specifically says it is for the 24V. I have not had time to work it out with Alldata yet.

 

[MCummings]

My truck does this High-idle thing also.



The times my truck does this is usually when not full warmed up. I haven't had the truck go to high idle when parked, but if I push the clutch in when decelerating, and let the RPMs fall from about 1,500 my truck will high idle (about 950RPM) till I slow to about 15MPH, then the motor idles down to "normal"



I have a new lift pump, new injection pump, and a new TPS (2,700 miles new now), and only have about 200 miles with new injectors and a PE COMP. I have not noticed this prob. since the BOMB's, but my injectors were playing havoc with my idle while they were still purging air out of themselves.



MerrickNJr