Constantly have to calibrate TPS

[ggrant3]

I have just started to drive my project car around and all in all it is running nice and smooth.

But I have noticed that every time I start TS, my TPS is off. Usually by 1 or 2 percentage points. Sometimes it is showing 1 to 2% and sometimes -1 to -2%.

It does this with the car running at idle and the car off, but key "on"

I have also tested this by calibrating the tps and letting the car idle. Then turning off the car and restarting ts (without touching the tps or pedal) and once ts starts the tps is reading wrong again and needs to be re-calibrated.

What can be causing this?

[Matt Cramer]

This can be a fault with the TPS or the wiring. Two key questions:

1. Where is the TPS grounded?
2. What is the ADC reading at closed and wide open throttle?

[arran]

Is "auto calibrate tps" enabled?

[kjones6039]

Is "auto calibrate tps" enabled?

What version is that in? Just curious......................

Ken

[ggrant3]

This can be a fault with the TPS or the wiring. Two key questions:

1. Where is the TPS grounded?
2. What is the ADC reading at closed and wide open throttle?

Actually I'm not sure where the TPS is grounded, but Matt you may know. It's the stock TPS (and wiring) for a '94 Ford Probe GT. I just tap'd into the factory harness at the ecu.

I am not at the car at the moment for the exact #'s, but I do recall the ADC for the closed throttle being 86 and changing to 88 when I recalibrated it on Sunday. But the 86 was from Saturday when I was driving the car.

[ggrant3]

Is "auto calibrate tps" enabled?

I didn't even know that was an option.

Where would I find that?

[nathaninwa]

Not sure if it's in ms2 and ms1, but ms3 has a feature called auto zero tps, not auto calibrate. Is check the wiring and make sure the tps is connected to sensor ground before enabling that feature

[ggrant3]

This can be a fault with the TPS or the wiring. Two key questions:

1. Where is the TPS grounded?
2. What is the ADC reading at closed and wide open throttle?

Okay, I'm in the car now and the ADC readings are: 88 Closed & 758 wide open.

Now maybe I am doing something wrong (wouldn't be the first time).

"But" when I just got in the car (without starting it) the reading was off, it was at -2% (ADC was 88). So I calibrated it and zero'd it out, which brought the ADC to 99.

Then I started the car and it showed it was now at +2% at idle, so I calibrated it again and zero'd it out, which brought it back to an ADC of 88.

All of these instances do not affect the wide open reading, that is always dead on.

Should I not worry about calibrating it when the car is off?

I think I am going to ignore the reading when the car is not running for now and watch the reading when the car is idling only. Because as long as the reading is correct when the car is running, obviously is the only thing that matters.

[ggrant3]

Not sure if it's in ms2 and ms1, but ms3 has a feature called auto zero tps, not auto calibrate. Is check the wiring and make sure the tps is connected to sensor ground before enabling that feature

Okay, that may be why. I am running MS2