E-fan controlling on 02 Chevy truck

[Taz]

Sorry ... I had made certain assumptions about what you and the other gentlemen had discussed off the Forum, when you were setting up the tune using TunerCat.

Yes, just like the A/C Pressure Sensor, the A/C Compressor Clutch must be wired the same as a Camaro. If you have AllData now, pull up a schematic of a 2002 Camaro - then look at the A/C Compressor Controls for an LS1.

Both your truck and a Camaro use PCM C2 pin 43 to activate the A/C Compressor Clutch Relay. The Camaro set up monitors voltage to the A/C Compressor Clutch - your truck does not.

So Yes, splice pin A of the Compressor Clutch (DK GRN wire) - and connect it to PCM C2 pin 18.

Also, the High & Low switches your truck came with should be bypassed - the Camaro uses only the input from the A/C Pressure sensor.


Regards,
Taz

[aaronr]

After spending hours of looking at wire diagrams and modifying my wire harness. I can not get the truck a/c compressor to cycle with 02 camaro tune. I can tell you the fans work great with the a/c pressure sensor but the a/c compressor won't look at no matter what i do. The only way I see to get what i want out of this system is to add relay to switch the clutch signal on and off with low side pressure switch to keep from icing the a/c system up. What do you guys think.

Here is the wire diagram method think to do.


The truck wire diagram

[Taz]

Something is not right ... could you post a log - with the first 5 or 10 seconds prior to activating the A/C - continuously logging to when the lines start to ice up.

It's been awhile ... think the A/C Pressure Sensor voltage PID is GM.ACP. Also log RPM, ECT, IAT, E-Fan status - and whatever else you think is relevant. The fewer PIDs the better - faster sampling, and easier for the brain to digest on playback.


EDIT: Also log A/C status, can't recall if there are any other A/C PIDs for the LS1-B PCM.

Regards,
Taz

[aaronr]

The A/C status "gm-accr" isn't supported on this pcm.

[Taz]

OK ... just trying to point you in the right direction ... connect to your PCM ... validate PIDs ... and select whatever A/C related PIDs you can ... as well as the other PIDs mentioned in post #43.


Regards,
Taz

[aaronr]

Taz,
I'm trying to get a/c system run off the 02 camaro tune so i can control the fan by the pressure sensor.

This file the compressors never cycles at all and the vent temp was at 20*
(2 truck with 02 Camaro system segment swap_0007.tun) goes with (truck tune with camaro system swap.efi)

When you look at this log file you will see that compressor is cycling with the truck tune. This tune will keep the vent temp at 40*
(current_0003.tun) goes with ( truck tune running ac sytem.efi)

any ideas??

[Taz]

Thanks for the logs ... they were helpful. Too bad GM.ACCR (Air Conditioning Status) is not a valid LS1-B PID (it is for Gen IV controllers) - it would tell us a great deal about what is happening with the A/C Compressor.

From the logs (especially the truck tune log) it seems that the A/C Compressor often disengages below 600 RPM - and when this happens, the A/C pressure drops off drastically.

Attached is PDF example of this, and a tune to try out - the idle values were increased to 650 RPM, and some other minor changes to the E-Fans.


Regards,
Taz

[aaronr]

Taz,
I think we are not on the same page here. I want the truck to run of the camaro tune that the only way I can have full control over the fans. Camaro tune is what ice system not the truck tune. If look at the camaro log and you will see the compressor wont cycle after high side gets below 150psl. That's why I want to put in the relay in. Thanks for info

[Taz]

I simply provided you with feedback on what I inferred from the logs you posted - a potential idle RPM issue - which may be a function an A/C table that is not accessible - who knows.

I posted some tuning suggestions in the truck tune posted. If you prefer to use the Camaro segment tune - just copy over the changes.

Not about being on the same page - it is up to you to get the A/C working the way you want - merely providing input / suggestions as you have been stuck a time or two on what to try next.


Regards,
Taz

[aaronr]

Thank you for your help and input.