mickytrus Posted February 26, 2014 Share Posted February 26, 2014 Hello, I am interested in testing a tps...... I have removed the TPS and have an ohm meter. Basically, looking for the overall testing procedure... testing resistance and resistence range.... Also, testing the voltage on the three wires going to the TPS... THanks, Micky Oh, symptoms...... car Idles beautifully........... try and accelerate and you would think the wires were crossed...... chuggs..... and doesn't even move...... press pedal to the metal.... and no difference at all..... so I am thinking either TPS or........ no electric getting to it........................ So when you describe.... use wire color if you can.... and reference pins by top pin of tps or middle or bottom... etc etc.......... Thanks, Again,,, Micky...... Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 26, 2014 Share Posted February 26, 2014 Overall resistance I don't remember offhand. But here's the basic. Either outer pin to the center pin, you should have either high resistance, gradually sweeping to low resistance (or vice versa depending on which pin you choose. Switching top to bottom will reverse the resistance reading.) as you turn the TPS. This is much easier done with the TPS still attached to the throttle body, so you can use the throttle lever to turn the TPS. The reading should be a smooth change (easiest to see with an analog meter if you have one), if the resistance bounces around a lot and goes off scale the TPS is probably bad. Wiring. Center wire is the signal wire to the ECU. Top and bottom will be either 5V reference feed from the ECU, or ground back to the ECU. Easy to tell if you unplug the connector and turn the key On, check each pin for voltage. You should also check the TPS voltage signal back to the ECU while it is plugged in. You'll need a paper clip or needle to stick in the back of the connector. Check the reference wire for 5v with the key On. Check the ground wire voltage to be sure you have a good ground. Should be very close to 0V no more than 0.1V. Check center wire voltage. Adjust the TPS until you have about 0.51V at the center pin. Then sweep the throttle slowly all the way to wide open. Voltage should climb steadily to about 4.2-4.5V. If you have a jumpy (up and down) voltage reading, or voltage drops to 0 while sweeping the throttle open, the TPS is bad. Quote Link to comment Share on other sites More sharing options...
mickytrus Posted February 27, 2014 Author Share Posted February 27, 2014 Thanks for the reply.... I just want to clarify so I better understand...... I bolded the topic.... and threw in a couple more words... Thanks, Micky Overall resistance: Ok, that sounds good..... I understand... that. Wiring Reference voltage, top and bottom pin while key is in on position ground to battery or any good ground....? (should be 5 volts) Tps voltage back to ECU: this would be the center pin(wire)(while plugged in) stick a needle or paper clip in wire, run to ground, voltmeter reading should be 5volts? Check the ground wire for a good ground. Should be close to 0v no more than 0.1volts( not sure here what you mean) which wire is the ground wire( basically, place voltmeter between it and ground..... (should be close to zippo in voltage?) no continuity Check center wire for voltage(not sure??? if you could clarify) Adjust the TPS until you have about 0.51V at center pin This would be key in on position..... using needle or paperclip..... throttle closed..... run to ground Do the sweep thing 4.2 - 4.5 volts check your sweep quality.... should be fluid no drops Quote Link to comment Share on other sites More sharing options...
mickytrus Posted March 6, 2014 Author Share Posted March 6, 2014 So ,,,,,, Here is what happenend... I have 5 volts with the key on. for the top wire in the plug..... I don't have 5 volts on the bottom wire in the plug So ..... I would like to know what to do next...... I figure it would be good to check the wire to the other end for continuity and I would also like to know where it goes....... What are the next steps to trouble shoot this here? Thanks a bunch Micky Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 6, 2014 Share Posted March 6, 2014 Then the bottom wire is ground wire, so there should be 0v there. That means the ground is good. The TPS signal at the ECU should be checked. You would have to get a factory service manual for the car and check which pin the TPS signal wire goes to in the wire diagrams. Have you checked for split vacuum/ breather/ PCV hoses? Checked fuel pressure? Replaced air/fuel filters? Quote Link to comment Share on other sites More sharing options...
mickytrus Posted March 6, 2014 Author Share Posted March 6, 2014 Then the bottom wire is ground wire, so there should be 0v there. That means the ground is good.ok, that's great.. I'll just test the sweep for voltage.... and adjust tsp....The TPS signal at the ECU should be checked. You would have to get afactory service manual for the car and check which pin the TPS signalwire goes to in the wire diagrams. Ok, illl work on that.(finding out which pin).... Where is the ECU located?Have you checked for split vacuum/ breather/ PCV hoses? Checked fuel pressure? Replaced air/fuel filters? Not to any great extent...... I did pull off the air intake last night.... those hoses seem.... ok..... I believe air filters.... fuel filters where already replaced...... (air filter is new) How do I check the fuel pressure..... I can go and purchase a pressure gauge/ fuel pressure meter.... etc if I have to ..... which one should I get?? Thanks, Micky Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 7, 2014 Share Posted March 7, 2014 Most parts stores will rent fuel pressure test kits for free. You pay a fee to get it, but get all your money back when you return the kit. You need a kit with a T fitting. Hook up between the fuel filter and the engine. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.