Hi, Shane
At 12:37 PM 3/3/01 -0600, you wrote:
><snip>
>Any idea what the the expected extremes for TPS operation are? I'm getting
>around 12.5 percent fully closed and 72.x percent fully opened. Hmmm - I bet
>thats in my powertrain diagnostics manual - doh! - I hate when I realize I
>should
>be reading the friggen manual (RTFM)... Shane
The F body boys say the voltage bump is made at 70% throttle.
I've also read of another TPS mod specifically done on a Chrysler product.
The author states that the information has been confirmed by certified
Chrysler techies
and extensive testing. I don't know what specific vehicle the author is
referring to but
it should serve as a pretty good guide.
For 1995 cars the TPS output voltage to the PCM varies from about 0.5 at closed
throttle to 3.7 volts at wide open throttle.
On 1996 and up the TPS output voltage to the PCM ranges from 0.35-1.03 at
closed
throttle to a maximum of 3.1-4.0 volts at WOT.
On 1996-2000 cars the voltage should never exceed 4.5 volts.
As the throttle is opened, the voltage should increase slowly.
He has a '95 and performed a TPS mod by drilling the attachment holes a
little larger
so that he could turn the TPS from its original position in order to
increase the closed
throttle voltage. If the voltage is too high at the 'turn' location,
you'll have to loosen the
2 screws and, with a scanner or DVM, move the TPS to set it at a lower voltage.
Chrysler recommends no more than 0.85 volts on the '95 because the PCM,
when given
very high TPS voltages, can "seek" and cause extreme rpm fluctuations. You
will
have to make sure that voltage does not go above the 3.7 or 4.5 at WOT for
your year
as well. He has been unable to locate the recommended high limit for
closed throttle
voltage for the '96-'00s.
My scanner showed on the last run of last year a closed throttle voltage of
0.68
and WOT voltages of 3.73 and 3.75 (hmmmm, air flow must have been really
turbulent).
Another TPS that I have shows sightly different voltage (cannot recall them at
the moment). I may try this on this other TPS this summer.
After he did this mod on his '95, his 'modded' readings were 0.93 volts
(closed)
and 3.6 volts (WOT), and he experienced no difference in his idle nor any rpm
wandering. He said that the difference in throttle response and crispness were
noticeable as soon as he pulled his car out of his driveway.
I think that he used a 1/4" bit to drill the holes bigger.
Happy hotrodding :-)
Bob
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