OK i know the reading should be .42 volts but can someone tell me where i need to place the red and black of the volt meter to read this?

 

Cheers

Black on the earth terminal of the battery and red in the middle pin of the connector on the flying lead that comes out of the TPS :)

Cheers Andy guess you just rotate it until the reading hits .42v?

 

That'll be the grey connector?

Actually also forgot to ask engine off or on or ignition on or off completely?

 

Cheers

Ignition on, yep undo the screws at the top and bottom slightly, and rotate to achieve desired voltage :)

Actually also forgot to ask engine off or on or ignition on or off completely?

 

Cheers

 

Alex,

 

1. Doing it with the engine running will make it a lot easier to "hear" when you're at the right voltage reading.

 

2. 0.42V is not an arbitrary figure. To set the TPS correctly you need to do three things: (a) disconnect the idle valve - this will diconnect the ECU from influencing the base idle; (b) set the base idle correctly (ca. 750rpm for a TT); and © then set the TPS. (If you had a ConZult this would be a matter of two clicks and Bob's your uncle ...)

When rotating the TPS to the correct setting you will come across a point where the rpm's pick up. This is the point where the circuit is "closed". When you're at that point you need to "rewind" the TPS slightly to a point just before the rpm's increase (at this point the circuit is "open"). This is the point where the TPS is set correctly. This may or may not be at 0.42V - on my car this point is reached at 0.45V. It is not too important where this point is, it is more important that the range is ok (ie 0.42V at idle and as close to 4.0V at WOT). Now reconnect the idle valve and reset the ECU (disconnect the battery for an hour or so after you're done. Reconnect and (hopefully) notice the difference!

 

If you perform the above adjustment with the engine off you won't know from your multi meter when you've hit the right spot.

 

I hope the above has been of some help.

 

Cheers mate!

 

Danny

Cheers Danny i'll try it soon.....

If the base idle is set correctly and also the TPS set correctly, then idle should sit nicely at 750rpm. If not then there's problems elsewhere! I've said it before and I'll say it again - don't fudge adjustments to achieve the desired effect, it will only cover up problems...

 

Danny this is in no way meant as a pop at you, more than likely thats the way you've been shown ;)

If the base idle is set correctly and also the TPS set correctly, then idle should sit nicely at 750rpm. If not then there's problems elsewhere! I've said it before and I'll say it again - don't fudge adjustments to achieve the desired effect, it will only cover up problems...

 

Danny this is in no way meant as a pop at you, more than likely thats the way you've been shown ;)

 

No worries Andy - it is indeed the way I've been shown to do it and have been doing it for some time now. To give some more info, I have found that many cars which pass through my hands have incorrectly set base idles. When you then proceed to set the TPS it is more than likely you'll set it at an incorrect setting. I agree that you should never fudge adjustments to achieve the desired effect and if the base idle is wrong then there are other problems present. However, to set your TPS at the correct voltage you need to have a correctly set base idle. Take for example a car I recently did a diagnostic on. Very high revving, ConZult indicated a base idle of approximately 1500rpm and a TPS setting of 0.18V! Early indications were that the TPS was faulty. I reset the base idle and then adjusted the TPS which finally settled at 0.43V. Now the engine is purring like a kitten. Just by resetting the TPS wouldn't have solved the problem.

 

Like you said Andy, I am not having a pop at you either, just illustrating what I've been told/shown and hopefully passing on useful info.

 

Cheers all!

 

Danny

Small but important addition to setting the TPS voltage correctly:

After the TPS has been set to the correct voltage, the TPS connector has to be disconnected and ignition has to be turned on for a short while.

This will clear the TPS selflearn levels in the ECU.

 

-Eric

Really odd, but I looked at one recently where the throttle closed switch wouldn't make with the TPS anywhere near 0.4v, had to wind it to 0.16!!

Suspect there's some bad wiring somewhere, so the +ve feed to the TPS is at too low a voltage or something. Ran out of time to check it over though.

Tried 2 different TPS though, same result.

I know this has been done before, but surely:

 

the TPS is a sensor - it needs calibrating... you set the voltages (which correspond to a mechanical position) and that's it... there is ONE correct setting. It is surely a function of the ECU to make any fine corrections as it's a reactive system bound by certain parameters??

 

SURELY, by 'fiddling' the setting, you are reducing the ability of the ECU to function correctly and, as said before, masking the underlying cause.

 

Rich

Really odd, but I looked at one recently where the throttle closed switch wouldn't make with the TPS anywhere near 0.4v, had to wind it to 0.16!!

Suspect there's some bad wiring somewhere, so the +ve feed to the TPS is at too low a voltage or something. Ran out of time to check it over though.

Tried 2 different TPS though, same result.

 

 

John, sounds like a classic example of a faulty TPS selflearn level in the ECU.

This problem should be fixed when you disconnect the TPS and start the engine (or turn ignition on).

 

Have you tried that ?

 

-Eric

No worries Andy - it is indeed the way I've been shown to do it and have been doing it for some time now. To give some more info, I have found that many cars which pass through my hands have incorrectly set base idles. When you then proceed to set the TPS it is more than likely you'll set it at an incorrect setting. I agree that you should never fudge adjustments to achieve the desired effect and if the base idle is wrong then there are other problems present. However, to set your TPS at the correct voltage you need to have a correctly set base idle. Take for example a car I recently did a diagnostic on. Very high revving, ConZult indicated a base idle of approximately 1500rpm and a TPS setting of 0.18V! Early indications were that the TPS was faulty. I reset the base idle and then adjusted the TPS which finally settled at 0.43V. Now the engine is purring like a kitten. Just by resetting the TPS wouldn't have solved the problem.

 

Like you said Andy, I am not having a pop at you either, just illustrating what I've been told/shown and hopefully passing on useful info.

 

Cheers all!

 

Danny

 

 

That kind of highlights my point rather nicely Danny ;) The only factor which will affect the reading from the TPS (assuming good power supply feed) is its angular position - its simply a potentiometer. The fact that you observed the idle being wrong even though the TPS was setup correctly shows that there were other problems with the car....

 

Cheers,

 

Andy

Therefore:

1.Disconnect the base idle valve.

2.Set the base idle around 750rpm.

3.Set the TPS.

4.Disconnect the TPS for a while or disconnect the battery for 1 hour.

5.Roberts your mums brother.....

One other point to note (lol will this ever end? :D). Its worth cleaning out the idle valve assembly if you are adjusting the base idle, since any crap in there will affect the adjustment ;)

Edited due to unhelpful comment. :D :duffer:

Danny / Duffers

are yu two speaking English?

I unnerstand nuffink from this thread!!!!!

 

Chris

:smw: where is my tps?

TPS=throttle position sensor

 

located on the left hand throttle body, black rectangular box :)

Therefore:

1.Disconnect the base idle valve.

2.Set the base idle around 750rpm.

3.Set the TPS.

4.Disconnect the TPS for a while or disconnect the battery for 1 hour.

 

Is the base idle valve the big grey plug that comes off the TPS?

Also do you disconnect the tps when setting base idle?

MMMMMMMMmmmmmmmmmm!

Short write up here http://www.twinturbo.net/net/viewmsg.aspx?forum=technical&msg_id=960871