Throttle Hesitancy - K Series

[Knighter92]

Evening All,

I have a throttle issue on my 2003 1.8K series. The engine continues to idle and drive like normal, except it's developed hesitancy in its throttle response. See video here: 

My initial thoughts are it's the TPS. I've re-calibrated it (Ignition, 5x throttle application, off) but that's made no difference.

I'm wondering whether to take the plunge and replace the TPS or if there is anything else I should/could investigate first? Faulty MAP sensor etc. 

If I am to swap the TPS, is it just a case of swap and calibrate as above, or do I need some additional electronic gubbins? 

Any advice much appreciated, Cheers! 

[revilla]

It looks from what I can see of the cam cover that you have an EU3 engine, with the coil packs on top of the head? If so the ECU will talk to an OBDII scanner (which can bought cheaply on eBay of you don't have one already). That will let you see live data for the important sensors. The TPS should usually report as 3.92% when closed and properly calibrated, going smoothly and progressively up to 90%+ when fully open.

The MAP should show about 100kPa with the engine not running (depending on the atmospheric pressure on the day). It should show somewhere around 35kPa at hot idle and should respond rapidly, although an OBDII scanner usually only updates once a second so it's hard to see.

Worth checking things like the coolant and inlet air temperature sensor values look sensible too. 

The scanner should also show any fault codes. Post the list up on here and we can tell you which ones you need to worry about (there will probably be a few spurious ones due to it not being in a Rover).

That kind of response can come from a failed MAP sensor, where the ECU starts using a calculated MAP estimate instead, but in that case there will be a fault case so it will be obvious.

I'd try to post up the scanner results before spending money on new bits at this stage.

[Knighter92]

Hi Andrew. Thanks for the reply and the advice. OBD2 scanner on order and I shall report back with the codes/findings