A/C Disable Settings

[TrekGTO]

Theres really nothing to "fix"

'PLEASE"

[BBA]

Log ETC Position and you will see 100%.

But that has nothing to do with it. It's is a TPS setting, not an ETC setting.

I'd like to know the fix as well.

[5_Liter_Eater]

I was wondering if 2.2 would help with this issue but it doesn't appear to have although the new MPIDs help to verify that it is not working. I currently have my AC disable set like:

RPM Disable: 4000
RPM (re)Enable: 3000
TPS Disable: 75%
TPS (re)Enable: 50%

I have added the status bits for AC Clutch, AC Disable (Pressure) and AC Disable (WOT RPM). I have seen the AC Disable (Pressure) kick in because I pipe my WB output through my AC Pressure input so when my AFR is leaner than ~17:1 the AC Disable (Pressure) status bit goes to "Yes" and the AC Clutch status bit goes to "Off".

I have looked at the parameters and descriptions in the demo version of EFI Live and while there are a few extra parameters in EFI Live they are only timers to say how long the AC will remain disabled, there is nothing there that I see HPT is missing to have this functionality work. I'm not sure if EFI Live users can verify whether this works or not a Gen 4 but it ain't workin' for us. Not sure if this is a GM OS bug or what.

[Kelp]

This works for me:

RPM Disable: 3500
RPM (re)Enable: 3400
TPS Disable: 30%
TPS (re)Enable: 25%

Car really kicks when the A/C goes off too. Right where you need it. My other tables complement this TPS threshold.

[5_Liter_Eater]

What vehicle? Are you seeing the AC light turn off or logging the PIDs to tell that it's kicking off?

[BBA]

I think he's saying he can feel it turn off.

As for using pressure to verify, you will go a good 15-30 seconds before a high AC pressure comes down anyway, so you can't tell by pressure at all.

If you really want to know, wire a test light across the AC clutch wires and test it while revving in neutral.

[5_Liter_Eater]

The status bits for AC Clutch, AC Disable (Pressure) and AC Disable (WOT RPM) should tell me the same thing. And they're telling me that it's not working.

[8850]

The status bits for AC Clutch, AC Disable (Pressure) and AC Disable (WOT RPM) should tell me the same thing. And they're telling me that it's not working.

I programmed mine at a low rpm, had my wife up the throttle way past my setting while I watched the compressor. It did not disengage. I agree, the program setting is not working.

[Ben Diss]

What's the latest on this? Has anyone figured out how to disable the A/C?

[5_Liter_Eater]

Press the button with the snowflake on it.

[Chris@HPTuners]

you need to set the RPM value to something really high for both. I said this many times now it doesn't work like the LS1. It only really disables via TPS. The RPM values only enable or disable the TPS check. The RPM must be below both of these values for the TPS disable to work. This is GM's screwed up system, not a problem with our software.

Set the Disable RPM to something like 7000rpm and the Re-enable RPM to say 7200. Then set the TPS values to whatever TPS you want the AC to disable and re-enable. eg. 80 and 75.

[Ben Diss]

you need to set the RPM value to something really high for both. I said this many times now it doesn't work like the LS1. It only really disables via TPS. The RPM values only enable or disable the TPS check. The RPM must be below both of these values for the TPS disable to work. This is GM's screwed up system, not a problem with our software.

Set the Disable RPM to something like 7000rpm and the Re-enable RPM to say 7200. Then set the TPS values to whatever TPS you want the AC to disable and re-enable. eg. 80 and 75.

Thanks! I'll give that a try.

[BennyHHR]

you need to set the RPM value to something really high for both. I said this many times now it doesn't work like the LS1. It only really disables via TPS. The RPM values only enable or disable the TPS check. The RPM must be below both of these values for the TPS disable to work. This is GM's screwed up system, not a problem with our software.

Set the Disable RPM to something like 7000rpm and the Re-enable RPM to say 7200. Then set the TPS values to whatever TPS you want the AC to disable and re-enable. eg. 80 and 75.

Chris,

That can't be good as stated. That would mean that "if" the above worked that the A/C would kick back in as soon as the TPS dropped below 75 at high RPMs. Not good for the compressor?

[8850]

Chris,

That can't be good as stated. That would mean that "if" the above worked that the A/C would kick back in as soon as the TPS dropped below 75 at high RPMs. Not good for the compressor?

I was thinking the same thing. After I make a pass and lift the throttle to idle position my rpm is still almost at shift rpm. Maybe the 7000/7200 rpm setting protects the compressor from over rev. I can read what Chris is saying but don't understand how that is controlling the compressor.

[5_Liter_Eater]

Chris,

That can't be good as stated. That would mean that "if" the above worked that the A/C would kick back in as soon as the TPS dropped below 75 at high RPMs. Not good for the compressor?

That something we need to test. I keep a demo version of EFI Live handy just to compare PIDs, table and descriptions. EFI Live has several other PIDs for the AC disabling. In addition to the ones we see in HPT there are also AC Disable Timer, AC disable max timer, AC disable TPS timer (all of which default to 6 seconds in the demo '05 vette tune), AC disable stall RPM and AC disable stall timer.

[Chris@HPTuners]

there is a seperate compressor protection disengage RPM, i didn't add it because i figured GM would have this set correctly and there would be no need to change it.

The WOT disable TPS is designed to increase vehicle performance, not protect the compressor. usually the minimum offtime is set in the 5-10s range, so the compressor is not going to re-enage as soon as you let off the throttle. I never heard of anybody racing their car with the AC on!!

I can add the other values if you think they are needed.

Chris...

[8850]

Sorry, I did not mean I race with the compressor on but I do test on open roads. On occasion I forget to turn my compressor off before making a WOT run. Just want to be sure I have programmed values that not only improve performance but protect the compressor.

[BBA]

I'll second the above comment and I would also like to see the additional values included.

[Kelp]

Actually the car has so much power in the summer I occassionally race with the A/C on. Why suffer?

[5_Liter_Eater]

Just tested this with Chris' suggested settings and it is still not working. The AC Clutch status bit never went to "off" and the AC Disable (WOT) status bit never went to "Yes".

Attached are the tune, log and config. Ignore the copious amounts of KR in the log.