EFIDynoTuning Forum

After installing electric fans on my truck I ran into the problem of ever time I turn the A/C on I get a rough/surging idle and the truck will die. The strange thing is that the wide band shows the truck to go from 14.6 AFR to 12; a data log shows the O2s to shift to the lower side of the mid voltage range. At first I thought that it was a low voltage issue (and it was pulling it down to 11.5vdc), so I got a shop to build me a good alternator that actually supports 130 amps at idle and a new battery and now I am getting 14.2vdc all the time like it should be. The issue remains the same: runs great until you turn the a/c on. It also causes the voltage meter on the dash to instantly jump down a couple of volts every time I turn the A/C on but yet a meter on the battery does not reflect this. I have opened up the wiring harness and been looking for a short or a problem but have not found anything. Any ideas on this situation would be greatly appreciated.

Sorry, this is a mass air conversion with an A9P and a Moates chip.

thats normal

run the fan relay trigger to ecu pin 41 using the fan wiring diagram under reference on the homepage.

That way the ecu can turn the fan on and off and also will kick it on when the ac is turned on.

Then just kick up the a/c iscdc adder so it doesn't drop idle when the ac is turned on.

Thank you for the quick response! I have my two fan relays being triggered off of pin 41 and working (high speed fan set up only). I also have pin 50 going to the 12v side of the A/C clutch so the eec will know the A/C is on. I don't understand how to get the fans to kick on when I turn on the A/C.

Also, I don't have the WOT A/C cut out relay in the system.

it kicks on automatically

are you uaing the latest a9l2 ?

No I am not, is there some parameters that need to be changed to make the fans come on when the A/C is turned on? Also, does the wire from pin 50 go to the "hot" 12v side of the A/C clutch power?

In Binary Editor, I only have the GUF1 strategy and I believe when I open the A9L2 calibration it doesn't make sense.

Sorry again, not pin 50! pin 10 to the a/c 12v side.

cant do it with BE have to upgrade to tunerpro