Ya know what has really got me baffled is I measured the resistance on the TPS
before I took voltage readings and the resistance overloads my Fluke at WOT...
Using ohms law (V=IR) shouldn't the signal voltage approach the input voltage
(approx. 5v) as R takes the big jump towards infinity at WOT?? What's in the
TPS that's stepping down or holding back the voltage?
Tom
____________________Reply Separator____________________
Subject: Re: DML: TPS voltage @ WOT
Author: <dakota-truck@buffnet.net>
Date: 4/25/00 9:38 AM
Hi, Tom
At 06:50 AM 4/25/00 -0400, you wrote:
>I finally hacked together some jumper wires and got a voltage reading of
.6v at
>idle and only 3.8v at WOT with an input voltage from the PCM of 5.1v...
My FSM
>specs call for approximately .25v at idle and 4.8v at WOT. I took the
>measurements with the key on and engine off... While it functions
smoothly you
>can see the voltages are off by a fair margin. Do you think this is a
problem
>or should I test it again with the engine on???
I've recorded runs down the 1/4 of the TPS @ WOT on 2 different TPS.
One TPS gives a min. voltage reading of .47v (engine on) and a WOT reading
of 3.65. The other gives a min. voltage of .68 and a WOT voltage of 3.75.
One source says WOT TPS voltage should be 4.5 or over, another says 4.8v, and
a third says at least 3.5v.
I really don't know what is what. Your message is the only response that I've
received and our TPS seem to be in the same ball park. This leads me to
believe
that the TPS that they put out for our engines are all in that range.
What bothers me is that, as far as I can tell, the TPS is a main player in
determining spark advance and air/fuel mixture. If WOT TPS voltage is really
suppose to be 4.5-4.8, then we are really not getting full potential
performance
at WOT. I've checked the tb plates with the pedal fully depressed and they
are wide open.
Thanks for the valuable feedback. The "BEAT" (search) goes on ...
Bob
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