[Mk2] [Turbo] TPS calibration?

[garry goodall]

Recently been experiencing hesitation and loss of power low down in the revs under light throttle n WOT (2k-5k), its like its missing but no backfire and holding back, after 5k its fine though and pulls like a train
recently changed leads, plugs (0.6 gap), dizzy + rotor arm, o2 sensor, and thinking about putting a new coil on, before this I would like to check that the TPS isn't screwing up the A/F mixture causing it to bog down.

How do you check the tps is calibrated properly?

thanks in advance

[garry goodall]

had it on code reader machine and it says it ok, 0% and throttle closed and 81% WOT

is this correct does anyone know, thought it would be 100% at WOT?

[Chris]

The WOT/idle reading is irrelevant to your diagnosis if the issue is within a rev range. The idle reading is incorrect, it should show a low percentage for the throttle plate being slightly open.

Have you monitored it from start to finish? Any sudden drops?

[garry goodall]

Ah so it should be more than 0%, I have moved the throttle and there are no sudden dips indicated through the machine that I used to test it! If I move the sensor past 0% it loses it's idle signal and begins to hunt ? Could it be that everthing needs setting up again I.e throttle butterfly screw and tps? I haven't adjusted anything does it lose itself after a while ?

[Chris]

Yes, you should see a low percentage at idle relative to the throttle plate position. Not 100% of the reading, but around 10%-15% should be about right.

You can loosen the screws on the tps, and rotate it slightly to set it. I would then carry out a hard reset (remove battery) to allow the ecu to reset.

This should then even out your WOT closer to 100%. However, don't be suprised if that is not obtainable.

[garry goodall]

Thanks chris, would the ecu reset set the idle position then as if I do set it to within 10-15% I don't want it to start hunting looking for an idle signal like it has done when I moved it before ?

[Chris]

That's what I am hoping should happen. Set it and then reset it. The ecu should then see the new reading as idle and not hunt. You can always mark the TPS and return it to the original position if it goes boobs up

[garry goodall]

Nice one I'll give it a try in the morning before work

[garry goodall]

Marked and took tps off, put it back on in the same place and it now reads 12 % idle so that's sorted, cheers Chris

[Chris]

Nice one bud. Does it idle any better? Any running improvement?

[garry goodall]

No it still runs xxxx, idles a lot better now though so that's one problem sorted, thinking it might be ignition timing ? It's booked in on rolling road tomorrow so that will show it up hopefully! Other than that I'm clueless lol

[danielmotegi]

can you not also measure the voltage coming from it, i remember in the ford days it used to go off voltages where we would measure the voltage at idle and get that matched up then try and get the full throttle matched as close as possible, was like a compromise as you couldn't get them both dead on,

maybe thats too old school now lol

[garry goodall]

yeah I do believe that you can test it that way if there were any known values to work from

Couldnt get it on the dyno but tuner seems to think injectors or a sticking valve is causing the problem, dyno next week will hopefully show it