Contour Enthusiasts Group Archives Forums Modifications Duratec Performance TPS MOD DONE !!

They theory behind this is to have the PCM dump more fuel at throttle tip in because it thinks the throttle plate is open farther then it is.

The theory is flawed and the PCM will tune out this mod.

When the car starts up and the PCM sees closed throttle position/voltage. That's the value it gives for closed throttle. In order for you to change that you would need to alter the TPS position enough to get past the low range of values so the PCM thinks the throttle is open.

This would slightly increase part throttle fuel enrichment. However it would also cause the car to run rich (as if it doesn't run RICH enough to begin with) This in turn would cause the PCM the "trim back" the fuel enrichment in order to stay around stoich. Therefore tuning out this mod.
OBD-II is all over part throttle A/F using short & long term fuel trim data. It will not let the car run abnormally rich (or lean)

I, of course, am the devil for mentioning this over & over... :rolleyes:

You could be right Demon. I promise I'll put it back to my stock voltage of .91 in a few weeks and see if it made a difference and report back ... suppose i should let the PCM adjust over a few days before reporting back?

I theorized that it screws with the load calculations (advancing ignition timing at part throttle) and that perhaps it causes more fuel to be sprayed at throttle tip-in (which could possibly cause a lean condition at WOT due the ECU's LTFT adjustments).

I did this mod just for the hell of it (before I pulled the secondaries). In fact, I set the damn thing for about 1.05 volts at idle, just because I could. It sure did change the shift points of my ATX.... it no longer upshifts early when I want to ride 3rd up to 55-60mph during light driving (for me). Throttle response seemed to have improved a little, but it could have just been the nice weather. I was going to switch it back to something below 1V (it was .92), but I think I'm going to leave it as it is... at least for a little while longer.

I use a paperclip for this method...

Thanx Greg.

Dan