How to make High idle work

[nonnieselman]

Hey guys,
I have a 2003 tahoe and im trying to figure out a way to get it to idle higher for winching and such.
Would it be possible to put a 5 prong relay on the IAT sensor and when its energized let it read straight to ground which should be about -40* and i tune that section (B4603) (B3618) (A0008) for a higher idle??
any other tables that would need adjusting?
Im running COS3 also.

Thats the only way i could think how to do it.

[Tinbender59]

i think the best way would be a solenoid, like the 70's cars used, messing with the ECU is generally a bad idea. ther is a product called "auto throttle" senses when battery voltage is below a set threshold, then brings the motors rpm up to stabilize the voltage level

here is one - http://www.kussmaul.com/091-84.html
and another http://www.vanner.com/manuals/02045.pdf

[nonnieselman]

The second one wont work with a DBW throttle..

The first one looks like it might work but i dont see how it would work with DBW also.

[Big Mike]

Always wanted to do it in the tune myself as well but could never come up with a way to do it safely and effectively via driver input. But Off Road Engineering does make a user adjustable high idle box that's plug & play for the 03-up DBW GM's.

http://www.offroadengineering.com/product-gmsuv.html

[RADustin]

what about a segment swap? from a vehicle that had a PTO or similar?

you still using A/c?

[DURAtotheMAX]

I wonder if you could use an 8.1 operating system, and then retune it for the LQ4?

8.1 OS's support factory high idle via the cruise control buttons, for PTO use in the HD pickup trucks.

[RADustin]

Is the 8.1L the only engine offered with PTO?

is the 8.1 coil on plug with high res crank trigger? or is it 4x with a dizzy?

hrm.

[RADustin]

I don't think a controlled vacuum leak will work. It will just make it run like crap.

You need to tip in the throttle some how.

Using the a/c circuits is one way. or an OS that had PTO or some 3rd party stuff.

Is the pedal a potentiometer or an encoder?

[DURAtotheMAX]

Is the 8.1L the only engine offered with PTO?

is the 8.1 coil on plug with high res crank trigger? or is it 4x with a dizzy?

hrm.

8.1 is coil on plug and drive by wire. Its basically identical "electrically" and "controls" wise to an 03+ drive by wire LSx. You'll just have to do some custom tuning to make the ECM work with a smaller displacement engine.

You might have to use an 8.1 throttle body and TAC module too, I dont know if the 8.1 ECM calibration will work with an LSx throttle body and TAC module.

The ECM's are the same (LSx and 8.1)...I mean for grins, you could just reflash your current ECM with an 8.1 calibration and see what happens????

[DURAtotheMAX]

I don't think a controlled vacuum leak will work. It will just make it run like crap.

You need to tip in the throttle some how.

Using the a/c circuits is one way. or an OS that had PTO or some 3rd party stuff.

Is the pedal a potentiometer or an encoder?

Its a potentiometer...but there are THREE, and they all sweep at different ranges/directions...so it would be somewhat complicated to make a fooler.

[DURAtotheMAX]

on the 8.1 calibration...there are two different transmissions that were offered with the 8.1. The Allison and the 4L80. Suburbans/Avalanches got the 4L80 and pickup trucks got the Allison.

The Allison uses a separate TCM...so you'll have to use a Suburban 8.1 cal....but then again, the Suburban 8.1 cal might not support PTO....I dont know though.

Maybe you can start with a pickup truck 8.1 cal and segment swap the 4L80 transmission segment? I dont know much about segment swapping on the LS1 PCM's.

Ben

[DURAtotheMAX]

The PTO-enable input is Pin 22, on the C1 connector (blue). Apply +12v to turn PTO functions on.

[RADustin]

8.1 is coil on plug and drive by wire. Its basically identical "electrically" and "controls" wise to an 03+ drive by wire LSx. You'll just have to do some custom tuning to make the ECM work with a smaller displacement engine.

You might have to use an 8.1 throttle body and TAC module too, I dont know if the 8.1 ECM calibration will work with an LSx throttle body and TAC module.

The ECM's are the same (LSx and 8.1)...I mean for grins, you could just reflash your current ECM with an 8.1 calibration and see what happens????


as long as the wiring diagrams are the same.

so doesn't an 8.1 not have cruise control? or is there a trigger switch to make the cruise control switches dual function?

I feel like a script could transfer the files over really quickly. and go from there...I never been inside an 8.1 file before though.

Do you have one that would have the high idle feature? Maybe only the system and/or engine segments need to swap over?




Its a potentiometer...but there are THREE, and they all sweep at different ranges/directions...so it would be somewhat complicated to make a fooler.

ahh- gotcha.

[RADustin]

The PTO-enable input is Pin 22, on the C1 connector (blue). Apply +12v to turn PTO functions on.

this could work.

segments on the 1mb are all in the same spot and same size. It should be no problem to move things around. Just need to know which segments to swap. Be great if we had two files identical, one with PTO, one without. Check the checksum/segment ID and see which are changed.

[RADustin]

wait- he said he is running COS3 but is an 03. I thought 03 was 1mb? there is no COS3 for 1mb so he must have a 512.

ecu number will be important to ensure he has the hardware.

[RADustin]

looks like once the 8.1 segments are there, a tech 2 is needed to adjust the parameters.

Not sure if these parameters are in the bin dump or somewhere in RAM.

does EFIlive have the PTO mapped?

[RADustin]

just checked- efilive does not have it mapped. nor does I believe hptuners.