Throttle Position Sensor

[John Robinson]

I have a problem of early upshifts so I had the diagnostics run on the car and it turns out that I only have 3 volts at the TPS.and it should be 5 Volts.

Transmission shop wants $150.00 to replace. NAPA Wants anywhere from $25.00 to $90.00 based on differant manufactures for the part.

I check the parts catalogs and the price is all over the place. Now I call Advance Auto Parts and they say they have it for $19.99.

My question is have any of you used the cheaper TPS and does it work as well as the higher price ones. I would appreciate opions based on good or bad experience with this part.:confused

 

[tigmaned]

i have a older C4 but the TPS is on the throttle body, isn't in the same place on a 93 vette? wondering why you have a price of $150 from a tranny shop? if its like a earlier model is simple to change, one plug and two screws. and with ours early ones need a voltmeter to adjust to .o54 volts. i get some parts from rockauto.com and they have more then one brand to pick from.
sorry i wasn't much help?

 

[jimmers]

i have a older C4 but the TPS is on the throttle body, isn't in the same place on a 93 vette? wondering why you have a price of $150 from a tranny shop? if its like a earlier model is simple to change, one plug and two screws. and with ours early ones need a voltmeter to adjust to .o54 volts. i get some parts from rockauto.com and they have more then one brand to pick from.
sorry i wasn't much help?

On my 90 the tps is also on throttle body. I just replaced mine this past summer and got it for $80cdn.

 

[geekinavette]

If you only have 3 volts at the TPS then I would investigate the ECM itself. The ECM must provide a 5 volt reference to the TPS....measured at the two end pins of the TPS connector. The center pin is the wiper lead of a potentiometer and will vary from a low voltage (around .5 volts) to a higher voltage at WOT (usually around 4.5 volts)...but the outer two pins must always measure 5 volts (or -5 if the voltmeter leads get swapped).

Replacing the TPS will likely not fix it if the ECM is only providing 3 volts. Check the voltage at the TPS connector with it disconnected from the TPS....if it's still 3 volts then you have an ECM or wiring problem.

Bill

 

[John Robinson]

What do I do

If you only have 3 volts at the TPS then I would investigate the ECM itself. The ECM must provide a 5 volt reference to the TPS....measured at the two end pins of the TPS connector. The center pin is the wiper lead of a potentiometer and will vary from a low voltage (around .5 volts) to a higher voltage at WOT (usually around 4.5 volts)...but the outer two pins must always measure 5 volts (or -5 if the voltmeter leads get swapped).

Replacing the TPS will likely not fix it if the ECM is only providing 3 volts. Check the voltage at the TPS connector with it disconnected from the TPS....if it's still 3 volts then you have an ECM or wiring problem.

Bill

Ok so if I understand what you are saying when I disconnect the wire from the tps there are 3 wires in the connector. Two are side by side and one is above them in the middle. I should be putting my volt meter on the two that are side by side is that correct? With the key in the on position I should have 5 volts between those two connectors ? This should not vary between idle position and WOT without engine running? Now as I understand it the center connector above the other two connectors should read .5 volts in idle position and 4.5volts wot with the key on. Do I put the + lead from the voltmeter in the pin hole and the - grounded on the block somewhere? Are there any tests to determine if the TPS itself is good since the above process is done with the wire connector disconnected from the TPS. Also when I put the tps on the shaft I have to rotate it until it slides over the shaft and then rotate it to put in the screws. Do I need to adjust the idle position on the other side so that the shaft and tps line up with the mounting holes without having to twist anything?:confused

 

[scorp508]

I'm not sure if L98 info is useful here. The L98 TPS is non-self adjusting, and your LT1 TPS is. I would check your manual for what the proper voltage is.

 

[DMGroh]

I'll be checking my TPS this weekend as part of a new opti install. I have the factory manual, so I know what to look for, and I'll let you know what I find out. This may or may not translate to a 93