Analog 4 - TPS Acting Weird

[Incognito G]

Hi guys, I need your help. I have Analog Input 4 wire to my TPS. The TPS has a 5volt supply, ground and the 5v output wired to analog input 4. The TPS was calibrated and reads 0 to 100%. However, when pressing the throttle lightly it will immediately jump to 100%. Depressing this the TP (Main) channel slowly counts down from 100% to 0%. I tried supplying Analog 4 directly with 5 volts, it acts the same way regardless if I use the TPS to output the 5v to AN5 or directly feed 5V to AN5. I'm using firmware 4.6.9 but this has been happening since 4.5. Appreciate your help.

[Denis Tan]

Hi, Not mean to be rude, but have you tested the TPS with ohm meter ? That will tell you if you have bad/wrong type of TPS. And please make sure the pinout/wiring are correct for the TPS you are using. Denis

[Incognito G]

Thanks for the concern Denis, I did test the TPS and its working fine. I also tested Analog 4 by feeding it directly with 5 volts, once I remove the feed to it the reading slowly goes down to 0%. I should not act this way, it should either be 100% when at full 5v and 0% immediately when I remove the current to Analog 4. Anybody experienced this?

[Rod Smart]

From a electronics side, Link systems would have filtering on the input of the analogue channels to stop HF from entering the system and making it unstable.

Each input would have a capacitor on each input pin to bypass this HF, if you connect +5VDC to the input, the input will be taken to a high state (100%), if the input is released to a Hi-Z (high impedance) the input cap will discharge through the internal circuitry, if the input is taken to zero with a ground/0V wire, the ECU will register instantly 0%

If you have a TPS installed, you hit full throttle, and its 100% (or max), let go and let it spring back, it will be instantly 0% or min setting.

To test that your TPS is working correctly, disconnect the centre pin from the ECU cabling, and put a volt meter Black from 0V (green) terminal, and the meter Red on the disconnected ANV4 terminal on the TPS side, as you move the TPS, you should have a smooth value of voltage from 0V (min) to 5V (max) across the TPS movement, if you have 5V at min and 0V at max, then you have the ends of the TPS swapped,

To test the input, (after verifying the TPS is correctly wired and working) reconnect ANV4 to the TPS signal, and look on the LinkECU software, also with a volt meter on that pin, and verify over the range of movement that at 0V (min) on the meter you have 0% on the screen, and 5V on the meter with 100% on the screen,

If there are still problems, and your measuring the voltage from the TPS at the TPS location, then check the same values closer to the ECU wiring, or remove the ECU and check the length of wiring form the ECU to the TPS with a ohm meter, you should have <2R (< 2 ohms)

[martin battye]

more than likely a switch type TPS or faulty wiring.

[Incognito G]

Thanks for the input guys, verified the wiring, all is good, tps has been replaced, still having the same problem. Had the TPS calibrated, when viewing using TP Main with the engine off, the reading changes when I press the throttle, when the engine is on its always at 0, however viewing by actual voltages shows changes

[Top Tune NZ]

have you tryed it in another an volt try one or two and see if it still has a problem

i have had a couple of issues like this but it was with an volt 2 where it shared with a di4 and there was a pull up on under the di side. you can email a log of it to me if you like and i may be able to see whats going on