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The mkiv Supra Owners Club

Throttle Sensor Problems - Help


Jive

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As some of you may know, my car has been off the road for the last couple of weeks due to a seized alternator, replaced the alternator today and the engine now fires and

is all back together. (Happy bunny so far :) )

 

Now, slight problem, when I took the throttle body off last

weekend, I made the mistake of taking off (ie unscrewed instead of removed plug) the sensor (circled) in the picture below.

 

image

 

When I removed the sensor I realised that it was connected to the throttle butterfly mechanism and then screwed it back on, when I've installed it we tested that the engine was idling correctly (with alternator installed) and found that the throttle would stick open and not close properly when your foot was taken off the accelerator - hmm slight problemobviously :(

 

We (Dad & I) found that if we released the screws from the sensor the throttle body would then start working properly. We've replaced the sensor about 4 times and removed the

throttle body completely and looked at how it slots in and had to resort to putting a couple of washers between the sensor and the throttle body just to get it to work properly (I'm well aware that this isn't correct but it was the only solution we could come up with to get it working) as per picture below.

 

image

 

When I took it for a test drive at first it was ok, came back and checked all the radiator levels, topped up and then went for another drive, this time it was bloody horrendous - with the car in D (3rd) it would get to about 2.5k - 3k revs then hunt ie rev drop rev drop rev drop etc until I came off the gas and then the revs would build up to the same point and do the same hunting again.

 

Got out, removed the plug this time from the sensor and carried on driving and it now works perfectly.

 

Could someone with a bit on knowledge on what this sensor does, explain how I can get it back on properly (without the washers) and without the throttle sticking wide open so that I can get the sensor plugged back in and working properly?

 

Help me folks, your my only hope :) :notworthy

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This is from the manual.

 

1. Loosen 2 set screws of the sensor.

2. Insert a 0.50mm (0.020in) feeler gauge between the throttle stop screw and the stop lever.

3. Connect tester probe of multimeter to the terminals IDL and E2 of the sensor (remove plug first)

4. Gradually turn the sensor clockwise until the multimeter deflects and then secure it with the 2 set screws.

 

Recheck the continuity between IDL and E2

 

Clearance between lever and stop screw 0.40mm (0.016in) should be continuity.

 

Clearance between lever and stop screw 0.60mm (0.024in) should be no continuity.

 

 

Hope this makes sense.

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Hope this makes sense.

 

Nope, you lost me at the "Insert feeler guage" :D

 

Hopefully my Dad will understand that and lend a hand - if someone can explain it better than the manual (ie in plain english) please feel free :D

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You may find that having the washers there is simpley making the sensors readings closer to what they should be.

 

You need to reset your ECU now because it'll have a faulty TPS code in the system, running it while the sensor is unplugged will create the fault code alone. It also won't hurt doing a reset after you've set the TPS up correctly so the car re-learns it values properly.

 

Setting the TPS up properly is actually quite simple, it'll all make sense when your actually looking at the parts concerned with the instructions above.

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Further to my last post, did you replace the gaskets for the throttle body after you took it off?

 

If you used the original gaskets you may have caused a small air leak, this would cause the symptoms your getting.

 

I recommend getting new gaskets, when re-fitting them, use Hylomar to hold them in place, it also acts as a sealent helping prevent air leaks.

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You may find that having the washers there is simpley making the sensors readings closer to what they should be.

 

We had to apply those washers because when the TPS was fully screwed to the throttle body the throttle would stick fully open as soon as I revved the engine slightly and that was obviously not good! As soon as the screws were loosened the throttle wouldn't stick open which led us to think that we'd installed it (the TPS) incorrectly.

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maybe the tps had washers on the screws when you took it off and you've lost them ;)

 

Do you think I'm that stupid :p

 

Nah, honestly there was deffo no washers on there when I took it off, it was snuggly up against the throttle body housing.

 

I've had a chat with my Dad and he's been reading the manual today and thinks he knows what to do (waves at Dad reading this thread :) ) - I'll give him a call tomorrow to see how to progress.

 

Still not sure about the feeler guage and where to put it despite reading the manual as well. :(

 

Any pics of the feeler guage etc would be appreciated. :)

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Could you have put it back on the wrong way so instead of the two metal arms just turning the sensor, they are jamming against it?

When I re-fitted my one the other day I put it on clear of the arms and then turned it round into position.

I get the impression the feeler guage goes between the throttle arm and the set stop screw on the opposite side of the throttle body, to give a little gap for tolerance when you set the TPS.

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On the throttle linkage where the cable runs to, if you look around there you'll see a stop point where the throttle rests against when its closed, it'll look like a small screw thread probably. Its between this 'stop' and the throttle linkage mechanism that the feeler blades have to go to set the adjustment for the TPS.

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Could you have put it back on the wrong way so instead of the two metal arms just turning the sensor, they are jamming against it?

When I re-fitted my one the other day I put it on clear of the arms and then turned it round into position.

 

That may well be very possible, when we installed the sensor onto the body, I think we tried slotting it onto the two prongs that protrude from inside but I also think we tried it both ways and got the fully open throttle both ways.

 

I get the impression the feeler guage goes between the throttle arm and the set stop screw on the opposite side of the throttle body, to give a little gap for tolerance when you set the TPS.

 

I've just pinched one of your pics from your thread, you'll see in my next post ;)

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On the throttle linkage where the cable runs to, if you look around there you'll see a stop point where the throttle rests against when its closed, it'll look like a small screw thread probably. Its between this 'stop' and the throttle linkage mechanism that the feeler blades have to go to set the adjustment for the TPS.

 

One of these two screws ?

 

image

 

PS : Thanks Rob for taking that pic, saved me going out to the car in the dark tonight :D

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Phew, finally sorted! Dad came round with his meter and feeler gauge and got the sensor readings correct. Also took the sensor fully off and reseated it properly - thanks Rob for suggesting the correct fitting :)

 

Took it out for a quick spin and it feels great and actually changes into 3rd automatically as opposed to last weeks driving having to be in manu mode just to get it to shift properly from 2nd to 3rd :)

 

Now got the O2 sensors from the manifold off and am currently soaking them in lemon juice although I've now found that one of the studs is knackered :)

 

Cheers for everyones help, as always :cool:

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  • 5 years later...

Okay thread revival here. I done the exact same thing as the OP. now car is acting like his was. I know I need to adjust the tps my question is though, do you simply just put the tps back on to its screw mounting points or, do you need to put it on to its mounting points then turn it 360degrees in either clockwise or anti clockwise. Been messing with it for ages now and searching the net for the answer to no avail. Thanks

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