Engine/Transmission (1998.5 - 2002) How to make a high idler for my truck?

[PatrickCampbell]

With winter coming, I want to get a high idle going on my truck.



I understand that the voltage on the APPS (Accelerator Pedal Position Sensor) ranges from around 0. 5 V to 5V. I found this out today by adjusting it (It was at 0. 30 V).



My thought is that I will have a stick hold the pedal at 1200 RPM and measure the volts at that RPM and then using a resistor and a ignition switched 12 v source, impede the 12V down to the proper voltage for 1200 RPM using a properly rated resistor.



A few questions:



A) Will this work

B) On the APPS connector pin out there's a bunch of other crap like Idle validation switch 1 and 2. Do I need to care about these??? I don't want to be throwing codes...

 

[Lordsman]

Ever thought of using a exhaust brake for warming up? It will run your egt up to 500 degrees with the heaters cycling and 400 without atb idle. You've got a manual transmission, and if you tow anything you'll love it for moderate or downhill braking. Just an alternative suggestion.

 

[Graphic man]

do you have the warm up feature turned on in the ECM?



it will run it at 1200 rpm



the dealer can turn it on for you





Scott

 

[CLamb]

What years can this warm up feature be turned on? On my first cummins truck(old TDR member back again ) I had an ice scraper that was a perfect 1200RPM when wedged between the seat bracket and the throttle. Amazing how much faster it warmed up.

 

[Huff N Puff]

I thought there was a PTO wire that you could ground to increace idle speed.

 

[Sea01Cummer]

Anyone know more about this dealer turned on warm up feature?



Steve

 

[Graphic man]

there is a setting in the ECM that if it is turned on and below a given temp it will go to a 3 cyl, warm up on start-up, approx 1200rpm and when you touch the break it will return to normal



i believe the only way to turn it on is at the dealer (scan tool) OBD2





Scott

 

[PatrickCampbell]

Exhaust brake is definitely something I would like but can't afford at the moment!



And the automatic high idler is nice but I want to be able to control it for a few reasons.



I want to be able to kick on the high idler in the winter when I am sitting around for a few minutes, or say, while I'm shoveling the snow off



Would like to be able to use it if/when I sleep in the truck to control the temps



Would like to be able to use it if I ever get a PTO.



Also would like to be able to use it if I ever get a high wattage inverter so I don't kill the batteries.



I have checked out the wiring diagram and from what I've determined the only thing that goes to the PCM/ECM regrading the accelerator pedal position sensor is a voltage reading. The APPS has idle validation switches to make sure basically that you really are moving the pedal, but once it gets beyond the APPS its all voltage so I will try to test out my theory today.

 

[Texas Diesel]

Anyone know more about this dealer turned on warm up feature?



Steve

It is not installed in all ECM's. If you go in and get any ECM update you will get it. The cold idle engine warming then must be activated by a DRBII scan tool. I had it on my 2500, the software came when Chrysler "fixed" my oil pressure problem by telling the ECM to ignor an out of range oil pressure reading from the oil presssure sender. I proved this by unhooking the oil pressure sender from the wiring harness AFTER the ECM update. Guess what? With no sender attahched I had 40 PSI. I had 40 PSI hot, cold, idle, red line.



My current 01 doesnt have the cold idle engine warming feature so I have a functioning oil pressure warning system.



I would rather have the dash chime, and turn on a red light if I lose oil pressue rather than the fast idle.

 

[Ram4Sam]

High idle??

TD, years back my truck got hosed by the dealer with that miserable oil press update. By your post, do you mean that the oil press ecm update includes the high idle feature? At what air temp does it activate? Since I am in So Cal, I doubt my truck will ever see temps cold enough to set it off, just curious as to whether there is actually a positive side to that god awful ecm flash.



Sam

 

[PatrickCampbell]

This is pretty much a done deal. I have tested this out with a 25 ohm rheostat hooked up to the #4 pin on the APPS and it effectively raised the voltage from . 50 to . 55. A 150 ohm rheostat will do the truck letting you swing the idle from idle to ????. One thing I'm not sure about is at what point the idle validation switches will get angry and stop allowing it... I'll keep everyone updated.

 

[lumberjack98]

Please do I am also interested in this feature

Thanks

 

[rockjeep73]

I have a Practical Solutions High Idler on my 2000, there is a small adjustment screw on it so that you can set the max RPM's that the idle adjustment knob will allow. The instructions say to set it so that the high idle does not exceed 1550rpm, as anything over this will set the check engine light and throw a code. hope this helps.

 

[PatrickCampbell]

Alright well, my truck is not letting me start now. I am HOPING I didn't fry the APPS. It is reading a full 4V now (???) It worked great in the engine bay, but of course by the time I got it all back together, something went wrong. If you do this, unplug your batteries because I either just set off some real annoying DTCs or fried something.



Basically, take the APPS off. and then get at the APPS wiring harness, this is the #4 wire which is the APPS sensor ground. It is the top left, if you are looking at the connector with the clip towards you. Cut it, and bring both wires into the cab.



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Put it back together nice and sturdy because its right by/on the engine

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In cab "ON/ON" switch with a 100 ohm resistor. In this picture, when the switch is DOWN, it uses the top terminal (so down=regular idle) and when the switch is up, it goes through the resistor. The middle terminal is the feed from the APPS--The top is the return.

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[BDMiller]

There is a much simpler way to do this- wire up a solenoid under the black injector pump cover. It would function just like those fast idle solenoids on older carburetors. I bought a kit do do just this from a guy (I think his name was Harold) on this board a few years back. It took 15 minutes to wire up & has worked flawlessly since.

 

[PatrickCampbell]

does that just push the spring?

 

[BDMiller]

On mine it pushed a lever.



Check this out



https://www.turbodieselregister.com/forums/showthread.php?t=90100