throttle pots....stupid questions i know
Discussion
Throttle Potentiometer is a sensor which informs the ECU of the position of the Throttle by registering a resisatnce against the position of the Butterfliy Spindle.
Therefor they are located on the side of the throttle body at the front of the plenum chamber above the alternator belt.
Typical running problems associated with a faulty TP are ... rough idle, no idle, poor throttle response.
Often it is the case that when they fail they only tell the ECU one resistance setting and therefor the ECU is fooled into believing that the Throttle is always in that position and therefor adjusts fueling accordingly.
Contained within the TP are a set of brushes which sweep a metal strip which increase or decreas resistance as they move.
As to what causes them to fail so much is open for deabte and often the manufacture of these items would seem to be to blame as it happens to too many people with differing driving styles, mileages and engine conditions for it to be down to them all the time.
Hope this helps !!
Cheers
Mark
Therefor they are located on the side of the throttle body at the front of the plenum chamber above the alternator belt.
Typical running problems associated with a faulty TP are ... rough idle, no idle, poor throttle response.
Often it is the case that when they fail they only tell the ECU one resistance setting and therefor the ECU is fooled into believing that the Throttle is always in that position and therefor adjusts fueling accordingly.
Contained within the TP are a set of brushes which sweep a metal strip which increase or decreas resistance as they move.
As to what causes them to fail so much is open for deabte and often the manufacture of these items would seem to be to blame as it happens to too many people with differing driving styles, mileages and engine conditions for it to be down to them all the time.
Hope this helps !!
Cheers
Mark
I fitted the 4.2 Cerbera TP yesterday to the S2 and have had no further problems, (after about 80 miles of varied driving from slow sightseeing to high speed dual carriageway).
Interestingly, when I fitted the new loom connector with the gold contacts, I noticed that someone, maybe the factory had soldered the existing loom connector into the loom some years ago. The colour coding sequence on the wires had been deliberately changed as well! Three wires connect into the loom: Green/brown; brown/black and plain brown. Plain brown and black/brown had been swapped around. I switched them back and when I started the car up, it would not idle! I then swapped them back to the way they were which was:
1) Green/brown
2) Brown/black which turns to plain brown
3) Plain brown which turns to Brown/black
The car runs perfectly but the wiring is in dispute with the TVR wiring diagram!
Has anyone else seen this?
Is it a case of "they're all like that sir"?
Jas.
Interestingly, when I fitted the new loom connector with the gold contacts, I noticed that someone, maybe the factory had soldered the existing loom connector into the loom some years ago. The colour coding sequence on the wires had been deliberately changed as well! Three wires connect into the loom: Green/brown; brown/black and plain brown. Plain brown and black/brown had been swapped around. I switched them back and when I started the car up, it would not idle! I then swapped them back to the way they were which was:
1) Green/brown
2) Brown/black which turns to plain brown
3) Plain brown which turns to Brown/black
The car runs perfectly but the wiring is in dispute with the TVR wiring diagram!
Has anyone else seen this?
Is it a case of "they're all like that sir"?
Jas.
quote:
The conversion has been done already by the sounds of it. I had to do mine when my first TP went. The colours sound right.
Cheers
Mark
Good point Mark,
I just looked into the old connector which I still have and the connections look like the standard copper ones, so why would the conversion have been done?
Jas.
Bought a New TP From Fords in Cambridge. This was the one which i had to buy the gold connecter to go with it. when i got it home and checked the wires, the colours of the wires were a different way round. The man at Ford checked out the back with the auto electricion who said to keep the wires on the connector the same way round and sod the colours. He said that it won't work the other way anyway. So solder in top to top, middle to middle, bottom to bottom irrespective of colour keeping as it was!
Hope this makes sense the way I've said it ?
Fords won't agree to a warrenty on the new TP unless you use the new gold connecter. Apparently the resistance on the old connector was suspect and may contribute to the early breakdown of the TP.
I suspect that this might not be the whole truth, and the real answer lies in the never ending story of the quality of the parts used by Fords.
(alledgidly)
Gadgit.
Hope this makes sense the way I've said it ?
Fords won't agree to a warrenty on the new TP unless you use the new gold connecter. Apparently the resistance on the old connector was suspect and may contribute to the early breakdown of the TP.
I suspect that this might not be the whole truth, and the real answer lies in the never ending story of the quality of the parts used by Fords.
(alledgidly)
Gadgit.
quote:
I suspect that this might not be the whole truth, and the real answer lies in the never ending story of the quality of the parts used by Fords.
(alledgidly)
Gadgit.
Hi Gadgit,
so you changed your TP already on your low milage S, too. This scares me. I wonder if it is a good idea then, that I take the S to a long journey to Sardegna, unless I have a spare TP in the boot, with all that connector stuff sorted out upfront.
Is there no way to swap the original Ford crap TP to a Bosch TP, since the Ford EFI is based on the Bosch L-Jetronic. I never heard of this kind of systematic TP problems on other cars who use full L- or LH-Jetronic (like my 18 year old Saab - don't even know where the TP sits...)
One reason that I found with the throttle pots going faulty (S2 47K and 3 TP's in 3K) was that the bonnet air intake is above this area and the plug connector can fill with water due to the design, best to tape it up with self amalgamating(?) tape to stop water ingress.
Cheers
LeeBee
P.S the wiring is correct, later TP versions (not made by Ford by the look of it) had to have the 2 outside wires swapped over due to a design change, the original set-up if left as per wiring diagram tells the ECU that the throttle is in the fully open position
Cheers
LeeBee
P.S the wiring is correct, later TP versions (not made by Ford by the look of it) had to have the 2 outside wires swapped over due to a design change, the original set-up if left as per wiring diagram tells the ECU that the throttle is in the fully open position
Leebee,
When you say the wiring is correct, do you mean to connect them , swapping the wires over, and connecting different colours, and keeping the same plug positions, or do you mean connect the same colours which changes the connectors at the plug?
Hope you understand what I'm on about!
Knowing you you'll understand.
PS any joy with me pipes! nearly getting to the stage of needing them (at last)
All the best
gadgit.
When you say the wiring is correct, do you mean to connect them , swapping the wires over, and connecting different colours, and keeping the same plug positions, or do you mean connect the same colours which changes the connectors at the plug?
Hope you understand what I'm on about!
Knowing you you'll understand.
PS any joy with me pipes! nearly getting to the stage of needing them (at last)
All the best
gadgit.
My first throttle pot went faulty due to water ingress, the 2nd went some time after so I am unsure if it was related as I had taken precautions to protect it, the 3rd one was faulty as soon as I fitted it but Ford did send it away for testing and admitted it was faulty (i.e not caused by me).The one I have now has been fine although I haven't done an amazing amount of mileage with it!.Gadgit I did a diagram of the wiring some time back, give me a day or so and I will post it on the net (where's best??) which will hopefully clear things up
Cheers
LeeBee
Cheers
LeeBee
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