VTPS but not with engine running (?)
 

Ok experts. This has got me stumped...:vash:

I installed my VTPS.
It moves full range mechanically.
I calibrated it by acquiring the min and max values & swapping a gage from the dashboard to verify that MS was reading the potentiometer full sweep.

I switched over to TPS based AE on the AE wizard menu and saved/ burned the MSQ to the ECU

I recorded a log with the ignition "on" as I stepped on the gas and it shows the TPS trace working fine but when I drive the car the AE action/change only shows occasionally in the logs.

Any ideas ?

BTW I want to use the TPS based AE to have better control/ recovery of my idle with AC etc...


Thanks

TPS AE isn't tuned.

Thanks ! You mean with the same settings it will show up on a log and then once the motor is running it does not ?!

I don't know if a log will show it but I attached one.

It is as if the 5V signal drops off or is reduced once the motor starts.

The log basically shows 3 full movements of the VTPS followed by 3 1/2 swings, 1/3 swings and so on.

There is no problem until the engine is started and then the VTPS movement does not show unless I stomp on the pedal.

Does that make any sense ?

Could my modification to the MS to accept the VTPS signal be wrong ?

P
:vash:

so on that log, when the motor is running, your stabbing the throttle fully?

Just about....:vash:

Weird, it seems sensitive enough when I am driving around watching the TP % gage on the TS dasdboard but it is damped on the log...

I have a feeling you hooked it up wrong, or somehow when the motor is running your bleeding voltage to ground.

Well, I don't think it is working backwards....

I found this but I'm not sure what if any applies to my PnP

http://www.shoptalkforums.com/viewto...?f=23&t=122132

My grounds have all been moved to two central locations to benefit the LC-1 groung loop thing....

I added some to the lower number and subtracted some #s to the top one and the log seems to show it as +3 instead of minus 1 at idle. Then I drove around the block and made sure that I stood on the gas pedal.
It shows a high reading same as the log with the engine off but the rest of the drive, it is as if I was driving at idle the whole time....

Poobs, did you ever figure out what was wrong? I may have the same issue..I thought my tps was a dud.

Well, first make sure it is wired right and mechanically moving smoothly.
Among other things mine was not returning to zero because I had taken play out of the cable.

Do a calibration, save it and then swap one of the gages to an ADC idle gage or anything that shows the values of the VTPS.

No matter what you do the logs will not show much change if you are running on the MS1 . This will make it harder for reading the logs.