Does anyone have a diagram on how this is done? my Drag Comp stinks when its cold out, I have all the parts but im not sure if you tap into just positive wire side of the iat, or do I tap into both of them, thanks for any help.

 

I have been playing around with the IAT sensor on my truck to get high idle to start at warmer temperatures. The sensor is a two-wire device that changes its resistance inversely with temperature. At 0*C (32*F) it should measure between 30K-36K ohm. At 25*C (77*F) it will be at 9K-11K ohms.

I will assume that you want to fool the ECM into thinking the temperature is warmer to keep it from advancing the injection timing. If this is true, you will need to put a resistor across the two sensor wires to lower the resistance. If you can tell me what temperature you need to stop the timing advance, I should be able to calculate a suitable resistor value.

 

My truck does it right around 40 deg, I installed a 1k resistor today, I scotch loced the 2 sensor wires and ran em into the truck, 1 wire goes right to the switch, coming off of the other side of the switch that is labled on I installed the resistor then ran it back to the sensor, however I cant tell if it works or not, the grids cycled a few times even with the switch on last night was the 1st time using this box and I could not believe how bad it was, my TST Catcher stack was bad also, but the Comp was worse, the one box that kinda handled it better was the Xzillaraider, any way im not sure if its hooked up correct, thanks for the help. its good to atleast figure out was has been causing this, It hit me when last night when my temp gauge was 180 it ran horrible, when it got up to 185-190 it ran better, I then pulled over and used my wifes expensive poster to block the radiator and whalla the stumble almost disappeared however once the outside temps get to about 50-55 the truck runs great.

 

Using a 1K ohm resistor will tell the ECM that the intake air is at about 75*C (167*F). I don’t know how Cummins programmed the ECM for high temperatures but that may be too hot. You might try a 10K ohm resistor to tell the ECM that the temperature is somewhere around 25*C (77*F).

Connecting one switch terminal to one sensor lead and the resistor to the other switch terminal, and returning the resistor to the other sensor lead, should work. (That was a mouthful) I think you have it wired correctly.

 

Thanks Bent, man your truck looks real nice, I did notice that using the resistor might have made my truck de-fuel a little later in the rpms here is a post that I found about using a 1k resistor, http://www.turbodieselregister.com/f...ght=iat+bypass
I just came back from a ride and it is still doing the shack rattle and roll, ill try the 10k tommorow.