Hi HT
Need some help with a throttle position sensor issue I don't understand-

With the car off and ignition in the on position, the tps works flawlessly, shows 0% at closed and 96.5% WOT, but when Im cruising, it will randomly start to jump all over the place and my afr will go crazy with it.

For example I will be driving along with the tps at around 12% open and then it will start jumping between 5% and 30% really quickly all over the place and my afr which is around 13.4 when cruising starts jumping all over between 10 and 15 and the car hesitates and you can hear the exhaust tumbling or something similar.

When I'm idling with the throttle closed the tps will be jumping up and down sometimes as high as 35% ? Is this IACV related at all?

Is this a voltage related thing? My crazy SPAL fan draws a lot of juice, could it be causing issues when it switches on?

Any help with this would be much appreciated. Sorry I don't know very much.

 

Is the sweep smooth from 0%-100% ? I have a tps that low and high were fine but everything in between was very choppy

 

the sweep is smooth from 0-100 when the engine is off and the ign is in the on position. When the car is running it isnt.

 

What EMS are you using?

Do you have access to another TPS?

 

if you are using a stock harness, the TPS, IAT and ECT share the sensor ground which is internal to the ecu. Make sure you are not having fluctuations with those sensors as well.

The TPS has a constant 5v reference which is supplied by the ECU, signal and sensor ground.

 

Op do you know how to use a multimeter? I'm going to guess a loose wire in your harness. Bumps in the road or vibration from the engine is causing the problems.


Have you swapped the tps out yet?

 

Rywire Tucked harness. AEM v2 OBD1 EMS.
Switching out to old OEM TPS tonight will post up again.
Yes I can use a multi meter will check for 5v const.
Thank you for all your help

 

Check for continuity at each wire to the ecu

As you are checking each wire tug on the wire harness in the cabin. You will most likely need two people for this.

 

Thanks for everyone's input. Confirmed bad TPS.
Should be noted that while sweep was fine with car not running it was still bad as vibration of the cars engine is what causes issues with the shitty aftermarket TPS.

thanks again