Engine/Transmission (1998.5 - 2002) High Idle, 3 cylinder, and overnight plug-in

[Billy Diesel]

Is there anyway to enable the high idle and 3 cylinder shut down even if the truck has been plugged in all night. I just got the program flashed yesterday, so last night, to test it, I didn't plug the truck in. It only got down to 0 or single negatives, so starting wasn't too bad this morning. The feature engaged as I went in and had breakfast, and for the first time since I bought the truck (year ago) I had defrosters on my drive into work (short trip ). I will always plug my truck in, but I would like to have my cake and eat it too! Maybe an aftermarket high idle is in order? Any suggestions?



TIA

 

[JJW_ND]

Get Harold Bowers (sp?) high idler

You should find several discussion on Harold B. ( mailto:rvhvnfn@juno.com ) high idle kit. Comes with everything you need to add a in cab switch controling a simple soliniod that pushes on you throotle linkage. It is adjustable so you can pick your RPMS. Simple, works great, no delay or warm engine effects.



jjw

ND

 

[Makensmoke]

... ... but that won't make your 3 cyl engage, which i also know is the cats meow for making cab heat!!!

 

[Mschevey]

I have been thinking of this too. I will try the following when I have some time and am feeling adventurous.



1 I think someone has posted resistance reading for the outside air temp sensor. Find the reading that relates to 10* or less.



2 splice into the line coming from the sensor to the ECM and install a SPTD relay. (single pole double throw)



3 Attach the line to the ECM to the common of the relay



4 Attach the normal sensor to the terminal connected to common for the non-energized position.



5 Attach a fixed resistor that equates to less than 10* outside air to the other terminal (connected to common terminal when energized. )



6 Install a lighted control switch in the cab to activate the relay.



Any time you flip the switch the ECM will think that the outside temp is less than 10* and if everything else is met for high idle, you get high idle plus 3 cylinder shutdown.



Any comments on this will be appreciated.



Mike Schevey

 

[Mschevey]

wrhuston: Just to note a few issues before you try this, If you beat me to it.



1 The outside air temp comes from the Battery temperature sensor NOT the Intake Air Temp.

The IAT is after the grid heaters so the reading from this sensor can not be used to measure the outside temp. With the grid heaters cycling the IAT will see approximately 65*F plus at 20*F. (The Battery temperature sensor is located under the drivers side battery. )



2 I don't know what the Ecm will do when the resistance (temp) changes by a large value instantly. It may set a fault code, this is especially true if it (the ECM) picks up the momentary interruption of the signal when switched from the dummy resistance to the actual sensor.



I would test the theory by removing the plug from the sensor and adding the fixed resistance to the wire when the temp. is to high for the feature to work. If the feature activates then use just a SPDT switch to see if the transition causes any problems. If not, then I would install the relay and control wiring.



Just some precautions I wanted to warn you of, Email me if you want to discuss this.



Mike Schevey

 

[Billy Diesel]

All right, starting over.....



Because it doesn't function when it has been plugged in overnight, it has to be a temperature sensor.



From the TSB, that leaves:



1. Intake Manifold Temperature less than 0°C (32°F) and,

2. Coolant Temp is less than 60°C (140°F)



And for the 3-cylinder, IMT is less than or equal to 15°F



If the IMT is taken from the sensor under the battery, then that can be ruled out. There is no friggin' way that is above 32°F when ambient temp is 0°F, it's been plugged in all night, and no high idle.



That leaves #2. , or different sensor. Since DC says to replace the sensor under the battery if the function doesn't work properly, apparently the IMT is taken from there. However, my temp gauge can stay below 140°F for a half hour with ambient at 5°F, and no high idle.



Is there possibly another coolant temp sensor?



Or... ... . IMT needs only to be less than 32°F for the high idle to start. The only temperature related disabler is coolant temp. This would make it possible to read the initial IAT, before the heater grid kicks in, and use that temperature.



Since the feature doesn't work after an overnight soak, the temp sensor has to be in the block, doesn't it?



Anyone else feel like I am running in circles?!?



Any other thoughts?



--

-Will

 

[Makensmoke]

will i think your on the right track, it makes sense what you say that they wont high idle after a good soak, they must read temp off the batt. i can see the ecm throwing a code with all the quick changes but the relay would be the ticket to all this if the ecm doesn't catch on. maybe even a double throw double pole one for high idle and one for 3cyl? or a timer on the 3cyl then down to high idle? if it worked a guy could make alot of friends selling that idea!