Hey, I have my SCT chip from my now sold Cobra and I'm getting a new program written for my 2003 FX4 with 4.6L. I'm going to tune it for 93, but I have some questions.

The electronic 4X4 setup--is there a significant increase in load if 4H is in use? And does the computer cut or advance timing when it's in 4H? Does timing change at all? I haven't seen the file for this thing yet, so I don't know how the values work yet. (I'm not writing the prog, I just have access to the file with the guy who is)

Also, I need specs on the 4.6L motor. Compression, injector size, fuel pump, etc.

Should I make multiple programs depending upon conditions that would create a greater load?

Also, should I make the shifts stiffer or could this cause issues with towing or going off road? Should I make the shifts hard only for wo throttle and keep partial stock?

My goal is simply to make my truck a little bit peppier and more efficient. The thing is otherwise stock except for the K&N, but I wanted to go ahead and write a prog for it just to get my bearings on the thing. I'm used to Mustangs, hehe.

Thanks a lot!

 

Anyone?

 

I don't think there is much difference between 2Hi or 4Hi. You are simply turning a second drive train and the power is evenly split between the two. I am sure that there is a difference between 2-4Hi and 4Lo becasue of the gearing. The t-case multiplies the ratios by a factor of 2.56:1. In an automatic the shift points would have to be lower in order to complete the shift before the engine reved to the limiter. The GEM controls the 4x4 engagement and it has a wire going to the PCM to signal it that the T-case is in 4Lo. On the Manual t-case the switch in the T-case sends a ground signal to the PCM when in 4Lo. So to answer your question the PCM only knows when the t-case is in Lo.

Regards

JMC