So my wife's 1998 discovery 1 v8 has a high idle, somewhere around 1200 RPM.

I tried diagnosing and come to the following conclusions. With the A/C on or off there is only a temporary change in the idle speed, so I ruled out the IACV.

When I remove the TPS from the throttle body, but keep it plugged in, the idle speed drops to 700RPM- which is correct.

So- I either have a bad TPS, or the computer needs to relearn what zero is when the TPS is actually installed and has some pressure against it.

My Question is should I:

A. Get a new TPS and take it to a Land Rover specialist to have the ECU reset to accept the new one
B. Simply have the ECU reset to accept the TPS as at "zero"
C. Look into a new ECU/TPS

The high idle was a bit of a sudden issue, and I am confused why this would be. I am not able to locate any vacuum leaks but could keep trying.

THANKS!

 

The best idea I have is to get a obd dongle and an app for you phone so that you can actually see what the sensors are sending to the ECU. You may need a new tps and you may need to re-flash your ECU. You can re-flash it yourself using robertf's application.

https://landroverforums.com/forum/di...33/#post598538

 

I have an ODB reader that is showing 11% on the TPS.

I have an IPhone but I will do some research on what you posted.

Edit, I see that it's mac compatible so maybe I should pick one up! If resetting is the best idea

 

11% TPS at idle sounds about right.


IIRC robertf's application only runs on Android devices.

https://play.google.com/store/apps/d...ms.gemsutility

 

So if unscrewing the TPS, but leaving it plugged in yields an idle at 700, what would you all do?

 

There's a free app that will allow you to reset the adaptive values in the ECU with a bluetooth dongle. It doesn't hurt anything to do it.

When I was chasing an intermittent high idle resetting the adaptives on first start would make it go away for awhile. Then it stopped working altogether. Then a few weeks down the line I'd be cruising along and hit random choppy fuel cut. Then when I ordered a $60 Jeep TPS it finally started spitting out TPS codes. Replacing the TPS fixed everything.

 

What year make and model jeep has the same TPS?

 

napa p/n: crb 21856

 

If you are strapped for cash, and don't have time to do the Adaptive Reset gambit, it is easy to file out the holes on the TPS a little bit and rotate it slightly CW, so the resting value is less than the base value memorized by the ECU. I did that to solve the high idle on my 96 D1 a few years ago. Whenever the TPS resting value is more than the memorized base value, the engine revs high at start. That is why taking it off works, since the value goes to zero. So that can happen with a new TPS as well, it just depends on your luck. That's why it is good to have a scanner that can show your throttle position, then write it down in your shop manual, just like me. Now if I could remember where that manual is.... PS That NAPA part (CRB 21856) is the IACV (also shown in the photo), not the TPS.

TPS rotated a bit CW