Engine/Transmission (1998.5 - 2002) High RPM

[Short Stack]

I drove from San Jose to Reno today and when I stopped in auburn and when I got to Reno my exhaust brake would shut of at 1500 rpm or would not work at all and when I stopped my engine was @ 1000 rpm at idle. So I shut off the engine and restarted and it was back to normal idle and the exhaust brake worked any ideas on what might be the problem?? no codes

Anybody ever had the engine run alittle higher?

 

[nps]

Sounds like your APPS might be going flaky given that the Ebrake was disengaging - thus the ECM thought you were fueling the engine. The APPS is what sends the throttle pedal position to the ECM.

 

[RustyJC]

Don't laugh at this question - it actually happened to another owner. Are you certain something hadn't slipped off the console and wedged against the accelerator pedal or between the accelerator pedal and the transmission tunnel? Maybe the floor mat was hanging up the accelerator pedal?



Rusty

 

[Short Stack]

o. k. no lol, but I am sure, it happened only after awhile of fwy driving. I have been running all around Reno today and it has been working fine, including the exhaust brake. We are going about 50 miles tommorrow so it will probably happen again. Going to go cruz by Forrest house, a (fellow TDR member) to see if he is home later since were in the area. I'll keep an eye on it, hopefully what ever it is it wil last untill we get back home on Sunday, to cold up here to be wrenching on the truck. Might be my APPS don't know.

 

[TRoyce]

High RPM and Exhaust Brake Failure

I have a 2001 Dodge with the HO engine, the 6-speed manual transmission, an aftermarket Pac-Brake exhaust brake, and about 77,000 miles on it. Everything else is stock. I have been experiencing a high idle (1000 RPM) and an exhaust brake failure on and off for over a year. On startup and short local drives everything is fine. If I drive about 40 miles on the Interstate, when I get off, the exhaust brake will not engage and the idle will be stuck high. The idle will not return to normal unless I shut the engine off and restart it. I do not have to wait long (30 seconds) to restart the engine. The other day, when coming off the highway, the exhaust brake was not activating, the idle was high, and the ABS dash light flickered a few times (new problem). I have had this idle/exhaust brake problem for over a year and it is really annoying me. The dealer doesn't have a clue, and they cannot reproduce the problem. The ambient temperature doesn't matter (90 degrees F, or 20 degrees F). Please help! Sometimes, the Pac-Brake will activate intermittenly when the problem occurs - in a 15 second 65 MPH to stop situation the exhaust brake might cut in and out two or three times.

I just signed up the the turbodieselregistry this week to find the answer to this problem. I hope it is out there.

 

[NoSeeUm]

TRoyce not expert here, but reading other threads I would look in the direction of the APPS.



Essentially, when you press the go peddle you don't open a throttle valve or mechinical linkage to increase fueling. All that really happens is that you operate a device (APPS) that tells the engines electric brain (ECM) where the desired throttle position is. Much like a rheostadt. There are also switches on the APPS that allow the ECM to tell if the go peddle is at the idle position.



A good chance your PacBrake looks at this gizmo (APPS) as well. There are ways to reset the APPS and ways test to see if it needs replacement or not.



Go to the TDR "Search" function and search for APPS.



Jim

 

[TRoyce]

Thank you Jim - your advice definitely gives me a place to start looking.

Tim

 

[Short Stack]

Thank you Jim - your advice definitely gives me a place to start looking.

Tim

Tim I will be taking mine to the dealer for other stuff but am going to see what they can do it happens every time I leave town to go fishing. Then went yesterday and it worked fine, don't know but I just hope it doe's not leave me stranded in the middle of nowhere. I will post the out come afterwards.

 

[HBarlow]

Gitten R Done,



Replace your APPS. That is the cause as others suggested. See my reply to TRoyce on his similar post in this forum on similar symptoms.



I have to carry a spare and replace the APPS on my truck every 40k - 45k miles. First symptom is always intermittent or no exhaust brake when slowing to exit the interstate. Next symptom is always higher than normal idle. If you continue driving and ignoring it the next symptom will be a dead pedal.



Harvey

 

[Short Stack]

Gitten R Done,



Replace your APPS. That is the cause as others suggested. See my reply to TRoyce on his similar post in this forum on similar symptoms.



I have to carry a spare and replace the APPS on my truck every 40k - 45k miles. First symptom is always intermittent or no exhaust brake when slowing to exit the interstate. Next symptom is always higher than normal idle. If you continue driving and ignoring it the next symptom will be a dead pedal.



Harvey

I will, went fishing on saturday check light came on, took it to a freind and he checked the codes= P0121 APPS. Still under warranty at least.

 

[TRoyce]

Thanks Harvey.

Tim