Mechanics

92 F150 CODE 634?

1992 Ford F-150 • 192,000 miles

Brother has this vehicle and the trans is early/hard shifting. He changed TPS on advice and now idle is higher and early shifting. Before it was late/hard shifting. I tried to read codes but info on reading them was way to confusing due to all the dont do this stuff. Including the 2 digit codes vs 3 digit codes. I did see a 634 code in sequence though. Dont know what that actually refers to. Before his CEL was off and on now it's on steady. Thanks
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Fixitmr
October 9, 2012.



Oh yeah it's a 302 and it has a trans kickdown cable I think. Has 2 cables 1 is cruise. Hitting gas does increse shift times somewhat but still shifts harder than should.

Tiny
Fixitmr
Oct 9, 2012.
Adjust the tps to.5 to.75 volts at closed throttle.

Start there

Roy
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Did not check voltage yet the tps is not adjustable as far as I can tell. But unplugged IAC and idle went down. While this helped with gear engagement 'bump' it did not change trans bang shifting at low throttle. Still got code 634. Also trans has NO kickdown cable.

Tiny
Fixitmr
Oct 11, 2012.
Brother had replaced TPS and vehicle drove accelerated but when I tested TPS for operation it did not change readings when he stepped on throttle. I watched some youtube vids about testing and saw readings change with throttle change. His is says at.8 if I remember correctly. I went to store and bench tested a unit just to make sure I did it right and store part worked fine changing readings. He still has unplugged iac for idle and now starts in 2 to avoid hard shifts.

Tiny
Fixitmr
Dec 13, 2012.

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