Page 1 of 1

Throttle position sensor

Posted: Wed May 25, 2016 1:29 pm
by ThatGuy
I'm having some problems with the tps on my altezza again, it started to play up a while ago and I managed to sort it by getting the car to run and adjusting it by ear until it idled fine.
But I went to adjust it yesterday to bring the idle up abit and it's somehow f*** itself. Ive checked the voltage going to it through the ecu which should read 0.78v from factory but the lowest I can get it to is 0.93v with it fully turned one way, which I think is causing it to idle at 3500rpm.
Does anyone have any ideas to sort it? I just don't get why it won't let me adjust it to where it is from the factory now even thiugh I had it running alright the other day.
Cheers for any help

Re: Throttle position sensor

Posted: Fri May 27, 2016 8:56 am
by RS Tom-Hundred
I know these can be a bugger and once you have touched them it can be a world of hurt to sort it! If all is well then I don't think you should ever have to touch them tbh.

Maybe the ECU has self learnt and tried to solve it but getting mixed up because the TPS is in the wrong position (after you adjusted it). Have you disconnected the battery overnight to reset everything? are the yellow paint marks still on it from the factory?

If I were you I would disconnect the battery and put it back to the paint marks/original position is possible. maybe clean the MAF and check resistance on the O2 sensor etc too. Then re connect the battery the next day. The car will idle high probably (mine always does after an ECU reset) for a day or two and then after that see where you are with the idle and voltage etc. Have you tried another TPS in case this one is faulty? If you can get hold of one even to borrow, that might be a next step if reset etc doesn't help :)

Not an expert on the TPS but that would be how I would tackle it ;)

Re: Throttle position sensor

Posted: Fri May 27, 2016 1:48 pm
by ThatGuy
Cheers for that bud, to be honeat I haven't touched my car since Monday but I was going to do as you say but pull the ecu fuse and try it in different positions and just keep turning the engine in and off as I thunk it might be taking the first adjustment and saving it so when I turn the engine off and adjust the tps it stays at the same rpm.
Ive had the tps off before but I got it to idle okay but didn't check the voltage if it, and now I can't get it any lower than 0.93v which doesn't seem right.
Annoyingly I cant borrow a tps as I don't know anyone with and altezza that's close to me :/

Re: Throttle position sensor

Posted: Sat May 28, 2016 3:56 pm
by ThatGuy
So I managed to sort the problem out once again, it seemed that when I had this problem before and had the throttle body off, I had adjusted the little Allen key screw that determines where the butterfly reverts back to at 0 throttle, so I've adjusted it out as it was causing the butterfly to not close fully so when I turned the engine on the revs would shoot up to 3K. Which has allowed me to get the voltage on my tps to 0.78v even though that wasn't the sweet spot for mine it's give me more adjustment and let me get the idle better than it has been :)