Jump to content
The mkiv Supra Owners Club

Throttle Position Sensor (TPS) intermittent harsh gear changes and idle problems


TubbyTwo

Recommended Posts

For a intermitant fault like this I would be tempted to just go straight out and bypass the original wiring straight away no point testing it as it may all be good when testing,

Give the plugs and pins a good wobble, test

Run a wire straight to tps , check

Then replace every wire to the tps,

its posible this could be a earth fault, with a wire just touching down to earth every so often?

 

Also is it always 10minutes for the fault to happen? Is it engine temp related? Ie could you let it warm up then drive it would be bad or if you drive straight away it will be okay until said warm temp?

 

A good start would be to try and bring the fault on , or make notes of when it happens and conditions , and see if they are the same every time , wobble the ecu plugs while driving.

Link to comment
Share on other sites

  • Replies 233
  • Created
  • Last Reply

Top Posters In This Topic

I think that since it is an intermittent problem there is connection most of the time. It'll only take 0.5 s of short or open to set the code and if he can drive it around for 10 mins or more before the condition is met multimeters are not going to find the problem. I still think that it must be a problem with VTA and simply running a new wire will tell us if that indeed is the problem. If running a new wire solves it he can try to find the error or just be happy with the new wire. When that is said I have previously had trouble with the pins of the ECU connector comming loose and it could be a simple thing like that so: When you get the plug of the ECU remove the yellow cap and check that the pins for the TPS are all locked in their seats.

Snap exactly

Link to comment
Share on other sites

When that is said I have previously had trouble with the pins of the ECU connector comming loose and it could be a simple thing like that so: When you get the plug of the ECU remove the yellow cap and check that the pins for the TPS are all locked in their seats.

 

This is exactly why I'm saying to check this area as best as possible first. It's less intrusive, and if you run a wire bypass you'll still be going through the ECU plug to reach the ECU. If it still doesn't fix it the temptation is to think the ECU is now definitely getting the signal when it might not be. I personally have had this problem with the VTA input on my ECU plug, the hole the ECU pin goes in to was too baggy - tightening it up fixed the issue.

 

Also, moving all the wires around while you're idling will show up an intermittent break more often than not. The ECU end of the loom is the most likely place for a wire break to crop up, failing that it'll be near the sensor plug end.

Link to comment
Share on other sites

Wow thanks guys!! Going to be a busy weekend then!

 

I will order the plug/pin parts tomorrow and get cracking from there. Will run a wire direct from sensor to ecu first before I go poking about with a multimeter.

 

Once I have reset the ecu and cleared the codes its usually around the 10min mark that it plays up again. Yet it will sit and idle just fine in P or N on the drive.

 

Bloody thing, I want to hate it but I just can't :D determined to fix it :)

 

Oh and I have already started on the beers in anticipation ;)

Link to comment
Share on other sites

Right so had the car on this morning before work, the battery was out being charged so any error codes are well and truly gone. Fitted the battery, started the car left in P and straight away this time the idle was all over the place, including the car stalling. Restarted it and went to take it round the block and straight away same symptoms again, gear slams, hangs at 3k rpm. Now I know it can run a bit differently when the ecu is reset as have done it a few times.

 

checked ecu and almost straight away this time error 41. So Its not temp related as the car would still have been cold, so going to poke the electrics this weekend :)

 

Its not going to beat me!

Link to comment
Share on other sites

Thanks mate, Lyndon on here has very kindly offered me some pins as he has a load spare :) going to test the circuit this weekend anyway so still got stuff to get on with.

 

Toyota did offer me the complete ECU block with pins for almost £200...... Poor guy didn't know what I was asking for lol

Link to comment
Share on other sites

TPS and ecu pin Ian to run a wire directly :) also gearing myself up to refurb all the electrical connectors, although gave them a wiggle with the car running and didnt make any difference. Ordered a new multimeter so waiting for that to arrive then I can start testing.

 

Note to self, dont leave multimeter on drive under passenger sill then go for a test drive.... crunch.

Link to comment
Share on other sites

TPS and ecu pin Ian to run a wire directly :) also gearing myself up to refurb all the electrical connectors, although gave them a wiggle with the car running and didnt make any difference. Ordered a new multimeter so waiting for that to arrive then I can start testing.

 

Ah right. I thought you'd just tap it into the stock wire as close as possible, at least you'd bypass 99.9% of the wiring that way if not the pins themselves, and it's free :D

Note to self, dont leave multimeter on drive under passenger sill then go for a test drive.... crunch.

 

I did that with the open tray of my old toolbox, backed over it and bent it all beyond repair. Supra survived without a scratch :blink:

Link to comment
Share on other sites

Ah right. I thought you'd just tap it into the stock wire as close as possible, at least you'd bypass 99.9% of the wiring that way if not the pins themselves, and it's free :D

 

easier to just cut both ends then and solder a wire in-between using the original pins?

 

Electrics are not my strong point :D

Link to comment
Share on other sites

I thought you were in the "testing" stage? You don't know it's the wire yet, so the quickest and least intrusive thing to do is to string a wire from the ECU plug out the window, draped over the wing and through the bonnet shut to the TPS :) Go for test drive. If it still goes wrong, you haven't wasted a day carefully routing a new wire and soldering it into place to replace a perfectly okay wire :)

 

If it was a permanent fix, I'd be removing the pin from the plug and desoldering the existing wire to do a proper job. But what's the point of doing that at this stage?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.