TPS at idle?

[Fran D]

I don't have access to my Ford manuals here, so I was hoping someone could fill me in on what the expected TPS% is at idle, warm with the AC off ('01 LC). I'm reading 17.4%, which seems a little high to me. The throttle is actually sitting against the throttle stop, which I have never changed.

The reason I'm asking is that the car threw a misfire at me this morning and when I went to take a look at the logged data it had stored the TPS at the time of misfire at 180%! Unfortunately, I didn't keep any of my old scans to see what the thing actually should read at idle.

Any help is appreciated.

[drzoidberg]

I have a 98 3.8L, and if I remember correctly I get around 17-19% on the TPS at idle.

I believe the TPS is nothing more than a potentiometer (ie variable resistor), and sometimes the low and high end of potentiometers are avoided due to potential nonlinearity at the extents, so I wouldn't really be surprised if that is the correct value.

[Fran D]

Thanks. I just know on my GM, idle is at a couple of percent. The big number kind of threw me, but I saw in my shop manual that hot idle can be anywhere from 0.53 to 1.27V (they don't give it in %TPS). That's a pretty big range, so I guess it's OK. Still don't know why it would say 180% on misfire, unless the data was corrupted in transmission.

[wiswind]

I once forgot to plug my TPS back in.......so I can tell you that it does not cause a misfire and your transmission will still be able to shift into all the gears.
However, when you push the accellerator all the way down, it will not "kick down" into "passing gear" with the TPS unplugged.

[Fran D]

No, what I meant by transmission was data transmission from the PCM to my scan tool, or even the stored value within the PCM was corrupted.

Either way, I can't get it to misfire again, so I'll need to keep looking for the next event.

[wiswind]

One thing that having the min and max values for the TPS not be zero (short) or open.....is then the PCM can detect if the TPS is unplugged (like I did) or shorted.....and it can then see that for what it is, a bad value.
In my case, I got the CEL, and no kick down when I would suddenly press the accellerator....but otherwise, everything was normal as far as drivability.