In reply to a message from LarryHartman sent Sun 17 Jul 2011:
Hi Larry,
Not sure about your question but here is what I experienced.
I first removed my old tps and found that one of the mounting ears
was broken off, but in place. Also the shaft on the unit was
sheered off, but at an angle…allowing it to work somewhat. I
repaired the old unit because a digital multi-tester on the red and
yellow wires showed voltage ranged smooth and proper as it was
supposed to according to specs. After epoxying the shaft and tab
together, I replaced it in the car and the results were less than I
had hoped for but all was working, but not well. I had a
fluctuation in the idle speed of around 50rpm…maybe…some
intermitent surging that was unexplainable. The car would start
fine the first time, but needed me to push the pedal down some to
start easily thereafter. It would start not pushing the pedal, but
would have to turn over several times first.
I took a ‘‘leap of faith’’ and decided that I would throw a part at
it and see what happened based on the obvious problems I was
having…with no explanation. I retested the old unit at least 2-3
more times before replacing it and every time, it appeared to be
working OK. I don’t think there is any way to test the old one and
be sure that it is operating perfectly due to the low current
readout and sensitivity of the tps…I just don’t think you can
ever be sure. If you are having problems that are unexplainable
and have checked everything else…you may also need to take
the ‘‘leap of faith’’ and just try a new part to see if it helps.
I firmly believe in troubleshooting and not just throwing parts at
something to see if it works…but in this case, I had tried
everything else and it was time.
Hope this helps some with your question…or maybe someone else,
with unexplainable issues with a poor running engine.
Next is the AAV or auxiliary air valve. I pulled mine and did the
hot water test using a thermometer and found that it was not
closing all the way. I did the temporary repair by crushing the
bulb/sensor some and that has worked out OK…but it is slow to
completely close and I am not 100% sure that it is even doing
that. This one is not a ‘‘leap of faith’’ since I can easily tell
what it is doing with the hot water test.
I have made some other improvements that Kirby and others had
documented such as removing the vacuum air valve mess and plumbing
the distributor directly to the throttle body, The AC compressor
hot wire now activates the idle air valve and works great, I
replaced the kick down switch at the throttle turntable, and made
all the adjustments to the throttle butterflies and linkage,
replaced the old Lucas windshield unit with a 1990 unit with the
better motor, 1990 honeycomb wheels and new Perelli tires, fuel
system cleaned…and on and on.
I drive the car almost every day since I got it running and love
every minute of it.
Front end rebuild, seat rebuilds, repaint, etc to come. I plan to
drive it until the wheels fall off!–
The original message included these comments:
The red slotted TPS, is there a way of checking it, to see if its
on the way out?
–
Bob Clinkenbeard 1987 XJS V12 Coupe
Locust Grove, Georgia, United States
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