LT1 PCM and aftermarket AC

[superfragl]

Hi all,
I got a 53 GMC truck with LT1 engine/4L60E transmission and PCM 16188051 out of 94 Fleetwood.
I installed an aftermarket AC system and wanted the compressor clutch to be controlled by PCM. Reason for that - proper fans and idle control, as well as compressor clutch control at certain conditions.
The problem I am having is - PCM would not command the clutch to engage.
The PCM has a bin from 94 Firebird flashed (same service number) because it has a subroutine for Performance mode.
AC request signal is wired via dash button, evaporator thermostat and low pressure switch. The rest of AC electrical part is done per Fleetwood service manual, including factory pressure sensor, clutch status signal, diode on the compressor, relay. The only thing missing is evap temperature sensor - I wired a resistor and the PCM sees 20 degrees Celsius all the time.
I deleted power steering sensor and EGR.
I attached BIN file and a zip with EEhack log file.
As I turn ignition on, PCM would test AC clutch successfully.
With engine running I press AC button, PCM sees the AC request signal, but the clutch would not engage. No codes are present.
If I command to turn AC clutch on, it will engage and AC on flag would set (not sure if that matters).
What I noticed when recording the last log is after I manually trigger AC on, then turn it off - fan1 would keep running for another 10 seconds or so and after the fan shuts off I would press AC button but PCM would not show request signal anymore until I restart the engine.
Please help - what am I missing?

[LeMarky Dissod]

Have you tried an otherwise identically written B- or D-car .bin file?
If 2nd gear start is disabled, Performance Mode should be enabled.

Think the pcm appreciates your request to turn on the AC, but is reserving its final decision to issue the command to turn it on, based on something missing or misconstrued.

If the AC still doesn't work using a B- or D-car .bin file, it's not either .bin file.

[dave w]

Perhaps the attached .xdf will help.

dave w

[steveo]

thanks for stopping in

i assume you're the fella that emailed me earlier.

i don't have time to review your data tonight but i'm sure if we keep talking we'll figure it out.

[superfragl]

Perhaps the attached .xdf will help.

dave w

Dave, thank you, I will take a look. Is there a specific parameter you have in mind?

[superfragl]

thanks for stopping in

i assume you're the fella that emailed me earlier.

i don't have time to review your data tonight but i'm sure if we keep talking we'll figure it out.

Steve, you are correct. Thanks

[superfragl]

Have you tried an otherwise identically written B- or D-car .bin file?
If 2nd gear start is disabled, Performance Mode should be enabled.

Think the pcm appreciates your request to turn on the AC, but is reserving its final decision to issue the command to turn it on, based on something missing or misconstrued.

If the AC still doesn't work using a B- or D-car .bin file, it's not either .bin file.

Original Fleetwood bin did not want to turn perf. mode on no matter what I have tried. As soon as I flashed Firebird bin (i had to match multiple parameters to original bin, like shift points, ignition tables, etc.) it worked just fine.
I will try flashing original Fleetwood bin back and see if that makes any difference.
Thanks

[superfragl]

Update. A/C is kicking in now - I flashed original B-body bin and AC works.
The situation with AC request not working after manually commanding clutch to engage is resolved too - it was just evaporator thermostat disconnecting the signal since it is cool outside now.
Performance mode does not engage anymore, which I expected. I looked for 2nd gear start enabled parameter and could not find it. Can someone advise on how to enable perf. mode on b-body bin? I am attaching it to this post.
Thank you all.

[LeMarky Dissod]

Forgot to change the filename, but I disabled 'Force Manual Mode in D2', which for whatever reason, enables the use of the Performance Mode table.

[superfragl]

That parameter did not help. However I changed both of these parameters
Force manual mode in D2 changed from Set to Not Set..
Single Manual/Perf Mode Switch changed from Set to Not Set..
And the performance mode light turns on and off now (which comes from PCM). If i monitor 'performance mode button pressed' in EEHack is shows up as always ON.
I guess, I will have to road test it, unless there is another way to confirm.

[steveo]

i think you're winning, that bit that's toggling to enable performance mode is probably the same one that enables those tables to be selected, so i doubt there's a way for the light to be on without switching to those tables.

[superfragl]

I hope so. The truck is not on the road yet. It will be a while.
Thank you all for your help!

[steveo]

if you really want to verify without driving it, i'm sure there's something in the "Trans" log tab (press the stream button to the right) that will change when you toggle the button. that'll be proof enough.

[superfragl]

I will be checking tomorrow. Thanks

[superfragl]

Tried checking parameters on Trans tab, but did not see anything change. The engine was not running, ignition was on.