Throttle Position Sensor (TPS) - HELP!!!!!!
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Throttle Position Sensor (TPS) - HELP!!!!!!
I have a 1999 F-150 with the 4.2L V-6. I have been having all kinds of transmission problems and a few others. The truck is shifting at weird times, popping hard out of gear when braking, and the check engine light is on. The transmission shop (just rebuilt the tranny twice)said that they think it is the TPS sensor. They showed me where it is and said it was just a bolt on part with 2 screws.
My question is:
What am I getting into by changing this? Is it easy to do and does it take any adjusting. It looks simple. Also, would a bad TPS cause these symptoms? Thank you so much for your help.
D Durrett
Houston, Texas
My question is:
What am I getting into by changing this? Is it easy to do and does it take any adjusting. It looks simple. Also, would a bad TPS cause these symptoms? Thank you so much for your help.
D Durrett
Houston, Texas
Senior User
Joined: Apr 2001
Posts: 105
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Throttle Position Sensor (TPS) - HELP!!!!!!
>My question is:
>What am I getting into by changing this? Is it easy to do
>and does it take any adjusting. It looks simple.
It is simple. But, you need a voltmeter to adjust it. Notice the slots where the screws go thru. I believe the usual procedure is to turn the TPS until it's output is a specific voltage (sorry, don't know the value - check service manual), when the throttle is closed.
>Also, would a bad TPS cause these symptoms?
I think it could (maybe).
The TPS outputs a signal of x.xx volts at idle and increases as you open the throttle. I think WOT should be 12V (not sure). If you check your old one, turn the ignition on but don't start the car. You will find one lead from the TPS outputs the small voltage at idle, then increases at WOT. Move it slowly from idle to WOT and monitor the voltage. Watch for spikes and drops. An analog meter works best for this. I am told that a bad TPS could be overlooked by the average voltmeter. When the TPS moves it can be giving a "noisy" signal, similar to turning up the volume on an old TV (the scratchy noise that you hear as you turn the ****). Using a good oscilliscope may be able to see all bad TPSs. But, they aren't that expensive. If it's in question, replace it.
Good Luck.
>What am I getting into by changing this? Is it easy to do
>and does it take any adjusting. It looks simple.
It is simple. But, you need a voltmeter to adjust it. Notice the slots where the screws go thru. I believe the usual procedure is to turn the TPS until it's output is a specific voltage (sorry, don't know the value - check service manual), when the throttle is closed.
>Also, would a bad TPS cause these symptoms?
I think it could (maybe).
The TPS outputs a signal of x.xx volts at idle and increases as you open the throttle. I think WOT should be 12V (not sure). If you check your old one, turn the ignition on but don't start the car. You will find one lead from the TPS outputs the small voltage at idle, then increases at WOT. Move it slowly from idle to WOT and monitor the voltage. Watch for spikes and drops. An analog meter works best for this. I am told that a bad TPS could be overlooked by the average voltmeter. When the TPS moves it can be giving a "noisy" signal, similar to turning up the volume on an old TV (the scratchy noise that you hear as you turn the ****). Using a good oscilliscope may be able to see all bad TPSs. But, they aren't that expensive. If it's in question, replace it.
Good Luck.
New User
Joined: Mar 2002
Posts: 10
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Throttle Position Sensor (TPS) - HELP!!!!!!
the TPS on your truck is a simple bolt on and really has no adjustment to it. Idle voltage is usually around .98-1.02 volts with WOT being 4.50 volts or above. (5.00 volts means shorted internally to referance voltage). The hardest part is usually getting the screws out to start with. They probably have a posidrive head on them(looks like a phillips, but it's not.)
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