89' 7M-GTE MKIII Supra TPS Issues

[tobsta]

Hi guys,
So basically my mate has bought a second hand Tubro MKIII Japanese import about a week ago and doesn't have an account here. I'm extremely interested in it also so i have created an account for the moment while he gets his stuff together. I believe we are having some problems with the TPS so I'll explain what has happened from purchasing it to about now, a week later.
So basically went to pick the car up and it was having some strange idle issues, really rough, jumping around and even sometimes stalling after 30 secs or so. The bloke informed us that the ECU needed some time to learn the idle settings again and after about 30mins of driving it should be sweet. Anyway after a 3hr drive home the problem persisted.
After doing some research i managed to get the ECU into diagnositcs mode and check for errors. The car spat out a 51 error, which is a TPS problem and after doing some further research on faulty TPS this seemed to fit the symptoms, e.g rough idle and hopping acceleration.
So today i went and had a look at the TPS with my mate and checked that the wiring and plug were attached well to the actual senson, pulled it out and ran the engine to check if there was any difference in the idle, which there wasnt. Plugged it back in and went for a drive, only to find that it now stalled almost instantly when left to idle.
Drove around to some mechanics to ask them for advice and none really wanted to help so I performed a check on the TPS to make sure it was in spec. It was way out of spec, for instance at 0.5mm throttle open it read infinite resistance. Plugged it back in and blew the wiring harness out and started the engine only to find that it was idling far better, but seemed to be a bit high.
So after all i think its definitely an issue with the TPS, and it may need replacing. What do you guys think would be the most likely problem and where can i buy a new TPS. Also will I need to adjust the timing after fitting a new one? The car is fitted with an e-manage and im not too sure if the timing has been adjusted with this? Will it need to re calibrated if it is?

Cheers
Toby

 

[tobsta]

Anybody?
Anyway I plan of taking the entire throttle body off, giving it a clean with carb cleaner as I have no idea if this engine has ever been pulled apart or not, cleaning the IAV and re-calibrating the TPS. Hopefully after this the problem will be resolved. I might plug the e-manage in as well and check what has actually been adjusted. The main question I have is will it be that necessary to redo the igintion timing? I mean if the timing is still correct, and the TPS is out of spec, surely adjusting the TPS to within spec shouldn't mean i need to redo timing will it? Im a complete noob to this but im willing to listen and learn.

Cheers

 

[Mike Morris]

Do you have any friends with a good running Supra? Swap throttle bodies if you do. Despite what is posted here most of the time when you get this code it comes from people trying to adjust the TPS(ie the two screws bolting it into the throttle body). I wonder if prior owner did that. Or its the rare instance that the actual sensor is bad

 

[tobsta]

I'm almost certain that the TPS is out of calibration because grounding the IDLE pin gets rid of the error 51, instead throwing an error 41. The idle problem is very strange. Sometimes the engine will run perfectly while others the idle will cause the car to stall when standing still. Are there any vacuum lines I should check for leaks around the throttle body?

Cheers
Toby

 

[mark3]

Have a look on www.mkiiisupra.net at the technical section and look for the guides, i did one a while back for quick TPS adjustment. All you need is a multi meter and a bent screw driver and it takes 10 mins to do, and you will need to check/adjust timing after to get best results.

Infact here it is,

http://www.mkiiisupra.net/bbs/showpost.php?p=317996&postcount=1

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