I am looking into doing the E-fan mod to squeeze a little more power and mileage out of my truck. I've have heard that there are many ways to do it, but the best way is to turn the fans on in the PCM. My question is can this be done with a handheld type tuner? Or do you need something like LS1edit. Also, will the computer have both high and low settings for the fans? It seems like everyone complains about their fans running on high all the time. Thanks!

 

A hand held will not be able to do it. A tuning software like HPTuners or EFI-Live can do it, not sure about LS1-Edit or TunerCats. For trucks 2003 and newer, they simply can wire directly up to the unused pinouts of the ECM, and simply set the calibration for two fans. The computer will run both fans much like it would on a passenger car. For 2002 and older models, those do not have the high speed pinout available (it is used by the HVAC). These trucks can use the low speed settings, but the high speed settings will need to be controlled by the AC Enable or some other trigger. EFI does have the option of re-assigning the pinout for the fans though.

 

It can be done with a predator, but it has to be done by getting a custom tune and then you can't make any adjustments. You could also just order a custom tune from somewhere like nelson's and have them enable the fans. Other wise you best bet will be HP tuners or EFI Live.

Most of the fan harness are set up to just get one signal from the pcm and the other from the AC wire. This can be fairly easily rewired to get both signals from the pcm. However, I'm not sure if a 2001 pcm is cabable of sending both signals. I think some of the earlier years used the normal high signal pinout for a different function just not sure off the top of my head what years. If you went this route then EFI live might be a better choice as they currently have more parameters available for adjustment in that dept. than HPT does.

On a side note I have had my fans wired getting just one signal from the pcm and the other from the AC wire for several months now. I don't have any problems with it that way, it comes on low when commanded, one fan on high and one on low with the ac on and both fans on high with the ac on and comand temp reached.

 

Hmm, so basically, if I tune the fans into the PCM, it will only be able to tell the fans to come on low speed? So my fans will never go on high? Sounds like you haven't had any issues with this? I don't really feel like having to turn on my AC to keep the truck cool. I'd probably forget or something...

What about the VSC option? I read that it controls the fans from 60-100%. I was curious to how you tune the VSC. I'm guessing it's adjustable, but does it use a laptop and software, or just some ***** on the VCS itself?

Thanks so much!

 

your fans go on high when you turn the A/C on..and no you dont need to turn the a/c to keep the truck cool.. the fans turn on low speed when the hit the temp its set for..

 

Yes, you can turn on the high speed fans using pin 33 even on the 2001 PCM, but you would lose the Auto Recirculation (max cool) feature on the a/c controls. Here is the description of it in a 2001 truck PCM using EFILive;
You would have to find that wire, hook it up to your high speed relay and then program the PCM. The PCM outputs "grounds" the fan circuits to turn them on. Hope this helps.

Ron