i have been having a tough time with my car running rich and i figured i would mess with some sensors and see what happens. i no the map snesor isnt easily changed without computer tuning so i left that alone. and the next thing i did was i tried too rotatte the tps so the pcm would see less voltage. this leaned the car out too hwere i wanted it so i was pretty happy. the old voltage was around 1.2 and i brought it down too about .50. everything was good and the only thing that i noticed was going too be a problem was the cold start. it still seemed a littel rich but that can be dealt with if it is only when its cold. does anyone have any experience with this type of mod that could give me some insight too what is going too happen. i really need too get this thing too a dyo too check the a/f ratio, but i would lkike too no before i go if there are going too be any problems so i can rule this out as a possible fix. thanks for the much needed help!

 

help please?

 

So basically the tps is .5 volts at closed throttle? I would think that this would cause the pcm to switch to the WOT tuning at a higher percentage of throttle. You should look into one of LM1 wideband AFR meters from www.Innovatemotorsports.com they're fairly inexpensive.

 

I'm not sure what you're asking?

TPS has a spec voltage for closed and WOT. As long as you're within spec then you're ok.
I'm not sure how playing with the TPS would lean you're car out at all? All it does is communicate with the PCM how much throttle you are aplying. And I think that everytime you shut the car off and restart it, the TPS gets re-zeroed. In other words, if you have the closed throttle tps at .5 volts the PCM will use this as its 0 reference point.

 

yep ,that is exactly what happened. i went too take the car out jsut now and it was rich again. i thoght it was gonna fix the problem but i guess not, lol. is there a sensor that i could manipulate too trick the ecu into makin it leaner that isnt gonna reset?

 

no, not really

 

is there anyway that you can trick the map sensor into seeing more vacuum at idle? i htink his woul dhelp out alot because of the cam. i think the cam is gonna be the whole problem since i havent been able too tune for it. thanks for all the help!!