Engine/Transmission (1998.5 - 2002) Need help. Truck idling high, dealer claims dead VP44?

[AndyMan]

Hey guys! Need a little help please.



I've got a buddy at the dealer with a 99 24v with 90,000 miles. Truck runs like a CHAMP. . However!:



It's idling at around 1300-1350 RPMs, and the dealer claims it's the Injection Pump, and wants $1800. He left the dealer and went to another local diesel shop. They also claimed injection pump dead as a result of dead lift pump.



There are no gauges, and no BOMB's. Totally stock CTD.



So can anyone help diagnose this? WHat I don't get is: If the injection pump is dead, how does it run at all?



Thanks a million for any help!

Andy



I originally posted this in the 911 forum, but came here as well for more exposure.

 

[AndyMan]

Looks like the 2nd repair facility checked the codes (duh) after installing a new VP44, and determined the problem to be TPS. Which I find strange, don't the 24v's have APPS not TPS?



Thanks,

Andy

 

[mbrolin]

They are one and the same. Throttle Positioning Sensor or Accelerator Pedal positioning Sensor. I suppose your buddy is still out $1800?

 

[AndyMan]

Believe it or not, the shop put his pump back on, and ate their labor costs... which I guess they should since they should've checked the codes first anyway... . Honestly, my bud should have checked the codes (although it's doubtful that he has any clue how).

 

[AndyMan]

Update and another plea for assistance:



VP44 has been replaced, no difference in behavior.

TPS/APPS (whichever it actually has) has been replaced, no difference in behavior.



Only code was TPS/APPS bad. Any other ideas as to why the motor won't come out of high idle?



Thanks for any help.

Andy

 

[otis]

A few weeks ago I went to shut my truck off and the idle was also around 1200-1300 and wouldn't come down. I turned it off and fired it up again and it idled fine but I had the APPS code (0122). It was replaced under warranty.

 

[Marco]

Ground

I've seen that a couple times.



All the sensors share the same ground circuit. When the APPS has a bad ground connection the Rpm goes up to about 1300.

All those grounds are connected to pin 11 on the ECM.



Most likely it's the engine harness that has a problem.



A simple test could be this. Pin 1 on the APPS is the ground circuit . Try to provide a ground from the battery negative pole to that wire and see what happens. If that works well, then you could simply provide the ground to the APPS permanently from the battery. Been there, doen that... .



Marco

 

[AndyMan]

EXCELLENT INFORMATION! Thanks, I'll pass that along, and post results.



Andy

 

[2-ND TIME]

high idle

Check to see if Cummins has a wiring diagram for you truck and if they have the resistance spects for the APPS and measure the diferent pins for the rehostat and idle - validation ccts . Or get cry--slurrr to provide it to you.

 

[Marco]

News?

 

[AndyMan]

Thursday, I had suggested he just go get the truck Friday morning and we'd look at it over the weekend, ensure the linkages, voltages, and codes were all good and verify it didn't have a switch.



Well, Friday morning the shop couldn't even get the truck to run at all, so the problem either complicated itself, or the shop has dorcked something up good. So, it's still there this morning I guess. I'll let you know the next chapter as it is written.

 

[muchsnow]

NEWS??? I have a similar problem.