High idle switch for interchiller

[bmiketuc]

I have a 2019 mustang with roush supercharger and Forced Induction stage 2 interchiller. The unit works great except at idle when the car is heat soaked. Remote starting will barely cool it off and sitting for long periods at the 650rpm idle it will creep up in cabin and interchiller temp. If i raise idle while in park to 1000rpm it cools much better and will not rise in cabin or interchiller temp. Is there any way to wire in a switch and program a high idle for remote start or while in park? While cruising the system has no problem on a 100 degree day holding 50 or below cabin vent temps and 45-50 interchiller temps with 70 IAT2 temps. It is not a condenser airflow or head pressure issue i have verified by watching discharge pressures. The compressor does not flow enough refrigerant for the load at idle and suction pressure rises with the load at idle only. It still cools but if idling for long vent temps will hit 60.

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[mejohn50]

The easiest option would be to do a PCMTEC Custom OS Multi-Tune and have your base tune slot be the high idle slot so it defaults to that every time you start it. Then you can add the normal idle to slot 2 or whatever and switch to that when you want. That way you would never have to remember to switch to the 1000rpm slot.

It’s also possible to setup the Multi-Tune to remember which slot it was last using. You could then swap to the 1000rpm slot if you knew you wanted that on your next remote start.

A hardware switch could also be possible. If you could trick the inferred engine coolant temperature into thinking it's really cold then it's possible you could make the switch work. The way I would test this is to figure out how the cylinder head temp sensor works, which looks like a 0-5v sensor with ~5v being the lowest output value. I would then wire a switch into that circuit that forces the output to the PCM to 5v, which should trigger the PCM to see something like -40 degrees F. If you do this with the engine off, that may trigger the engine coolant temp reading on the next engine start to be low, which could then be used to trigger the cold start idle speed, which you can have set to 1000rpm or whatever you want. I have no idea if this will work and I have never tested this theory on an S550.

Personally, I would do a Multi-Tune slot with a 1000rpm or whatever idle speed, make sure I have tune slot memory enabled in Custom OS, and then flip to that tune slot before shutting the car off if I knew I wanted to run it with a high idle after a remote start. That will accomplish exactly what you want without any added hardware, just flip slots with the cruise control buttons.

 

[bmiketuc]

Thank you. That would work for me being on a switch when needed. Ill look into how to get that setup.

 

[bmiketuc]

My hptuners will not read the encrypted roush tune file will this be a problem for PCMTEC?

 

[mejohn50]

My hptuners will not read the encrypted roush tune file will this be a problem for PCMTEC?

Is it a Roush file or is it from one of the mainstream tuners?

If it's a Roush file, then HPT or PCMTEC should be able to support it, you may have to request your specific OS be supported if it isn't.

If it's a mainstream tuner file, like Lund or whatever, then PCMTEC or HPT will not be able to read it.

 

[bmiketuc]

I honestly do not know for sure. I bought the car with the supercharger installed and judging by the car fax data it looks to be factory installed and all maintenance done by ford. When i try to read with my MPVI3 it will not read and pops up error messages. I need to get it tuned.

 

[mejohn50]

I honestly do not know for sure. I bought the car with the supercharger installed and judging by the car fax data it looks to be factory installed and all maintenance done by ford. When i try to read with my MPVI3 it will not read and pops up error messages. I need to get it tuned.

What error does it give you? Are you running the latest HPT beta?

 

[bmiketuc]

I believe it said file not supported. I was using latest stable version from website.

 

[mejohn50]

Post up a screenshot of the error when you can and use the latest beta from the HPT website.

 

[engineermike]

If it’s locked by a 3rd party tuner there are people out there who can unlock them for about a hundred bucks.

 

[bmiketuc]

I was able to read and save a copy of the tune using the beta version. Not sure how to tell if it’s a Roush tune or if it’s been changed. Idle is set 650 P/N and 600 Drive. Can it be raised some without needing a separate tune for now. Seems a little low which may be why even before the interchiller it cooled not so great at idle.

 

[engineermike]

You can find a stock roush tune posted in the forums and compare it to yours to see what was changed if anything.

 

[Rolls]

I'm sure there is an ect/wot and possibly iat idle adder you can adjust to simply raise the idle if the ect is too high. I bet an hour digging through all the tables and you will find it in PCMTEC

 

[bmiketuc]

I could not find any Roush tune files to compare mine to. At least I have a backup copy now if needed. What rpm do 2019 stock gt cars idle at in park? I found the climate control idle speed adder for park/neutral

 

[mejohn50]

This is from my stock 2019 Mustang GT auto.

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