Tps Help!!
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Joined: Jan 2007
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From: Tempe, Az, 85284
Tps Help!!
I just bought a 88 hatch with a ls motor. The guy I bought it from told me the ecu and dizzy are obd0 and the injectors are obd1. The car runs perfect with 85 percent throttle or less but if you floor then it bogs down to around 1700 rpms. I was checking all the wireing and found the tps wires green/white and yellow/white were never switched with eachother and I read a diagram saying they should be so I tried switching them and now my problem is opposite. It bogs at around 1700 with 15 percent throttle or less and is perfect if you floor it. My question is do you think I need a new tps or just need to calibrate it or what? Thanks
Junior Member
Joined: Feb 2009
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From: California
Re: Tps Help!!
TPS is a variable resistor sensor. you will more than likely have a break in the resistor at a certain throttle angle. this can be verified by a signal drop-out if you hook up a scanner while watching the output signal of the TPS while slowly opening and closing the throttle valve.
TPS is also a input sensor, and no other sensor dictates its operation. it basically tells the ECU what angle the throttle is in.
if you don't have access to a scanner, just replace the TPS and update us on your progress.
TPS is also a input sensor, and no other sensor dictates its operation. it basically tells the ECU what angle the throttle is in.
if you don't have access to a scanner, just replace the TPS and update us on your progress.
Re: Tps Help!!
Sounds like a MAP sensor problem to me, but start off with TPS since that's where you are at now....
You're supposed to use the scanner to check the TPS voltage and adjust it accordingly or to diagnose bad sensor. You can also check TPS voltage using DVOM which works the same as the scanner, but not as simple. If you instruct the guy to change his TPS, he will have no way of adjusting it to the proper voltage and will either get 1 in a million lucky or have problems again.
First thing you need to check is if someone accidentally switched the MAP and TPS harness plugs around (This is extremely common), then if that's good, proceed to checking TPS voltage. Take a DVOM (Digital Volt/Ohm meter) and probe the two outside wires in the TPS plug (there's three wires) while it's still plugged into the TPS. Turn the key on, with engine off and look at voltage. Voltage is supposed to read 0.5V at closed throttle and 4.5V when at wide open throttle (WOT).
If you have a JDM throttle body and the voltage is incorrect, there'll be screws that hold your TPS sensor into place. Loosen the screws and move the TPS sensor either clockwise or counter-clockwise until 0.5V is reached at closed throttle, then tighten the screws and check voltage at WOT. If it is correct at closed throttle, but incorrect at WOT or you can never achieve 0.5V at closed throttle, then the sensor is bad and needs replacement.
If you have a USDM throttle body, the TPS sensor will be riveted down, so if the voltage is incorrect, you need to remove the throttle body, get a flat chisel and hammer a groove into the rivets, then use a flat screw driver to spin them out. Find new screws to re-install into the TPS holes when you put them back together.
If you find the problem isn't your TPS sensor at all, it could be an ignition issue, so proceed to checking the coil and distributor and MAP sensor if TPS doesn't solve problem.
TPS is a variable resistor sensor. you will more than likely have a break in the resistor at a certain throttle angle. this can be verified by a signal drop-out if you hook up a scanner while watching the output signal of the TPS while slowly opening and closing the throttle valve.
TPS is also a input sensor, and no other sensor dictates its operation. it basically tells the ECU what angle the throttle is in.
if you don't have access to a scanner, just replace the TPS and update us on your progress.
TPS is also a input sensor, and no other sensor dictates its operation. it basically tells the ECU what angle the throttle is in.
if you don't have access to a scanner, just replace the TPS and update us on your progress.
You're supposed to use the scanner to check the TPS voltage and adjust it accordingly or to diagnose bad sensor. You can also check TPS voltage using DVOM which works the same as the scanner, but not as simple. If you instruct the guy to change his TPS, he will have no way of adjusting it to the proper voltage and will either get 1 in a million lucky or have problems again.
First thing you need to check is if someone accidentally switched the MAP and TPS harness plugs around (This is extremely common), then if that's good, proceed to checking TPS voltage. Take a DVOM (Digital Volt/Ohm meter) and probe the two outside wires in the TPS plug (there's three wires) while it's still plugged into the TPS. Turn the key on, with engine off and look at voltage. Voltage is supposed to read 0.5V at closed throttle and 4.5V when at wide open throttle (WOT).
If you have a JDM throttle body and the voltage is incorrect, there'll be screws that hold your TPS sensor into place. Loosen the screws and move the TPS sensor either clockwise or counter-clockwise until 0.5V is reached at closed throttle, then tighten the screws and check voltage at WOT. If it is correct at closed throttle, but incorrect at WOT or you can never achieve 0.5V at closed throttle, then the sensor is bad and needs replacement.
If you have a USDM throttle body, the TPS sensor will be riveted down, so if the voltage is incorrect, you need to remove the throttle body, get a flat chisel and hammer a groove into the rivets, then use a flat screw driver to spin them out. Find new screws to re-install into the TPS holes when you put them back together.
If you find the problem isn't your TPS sensor at all, it could be an ignition issue, so proceed to checking the coil and distributor and MAP sensor if TPS doesn't solve problem.
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