Come off it Halmer.
What is a throttle? A progressive swith that activates an opening within a pipeline feeding a carburettor or metering device.
What is a potentiometer? A device measuring a changeable output to a variable input.
Press your foot on your accelerator and your car moves, unless it's a Fiat.
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Hi,
I am not a tech head so i will try and explain best i can!
It is a kind of multi position electrical switch atatched to your accelerator pedal. It is used on modern cars instead of a throttle cable.
The more you press your accelerator the further round the potentiometer moves and this electrical signal activates a small servo on the throttle body.
I am sure someone can describe it better but in general it replaces the mechanical cable mechanism with an electric one!
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It is an electrical device to monitor the position of the throttle. It works as a variable resistor (very similar to the device behind an old fashioned radio volume control). There are usually three wires to it - supply, earth, and signal.
The voltage output should vary smoothly, with no sudden jumps. Usually it should never reach either earth or supply voltage at either end of its travel.
The voltage on the signal wire increases smoothly as you open the throttle. This is sensed by the engine management unit, and used in its computation of fuelling and ignition parameters.
number_cruncher
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Thanks
The reason that I asked is that when you change gear and take your foot off the accelerator on my wife's Punto, the revs seem to increase instead of holding then dropping (if you get my drift).
I read somewhere that some Puntos had problems with their throttle potentiometer and wondered if this car has that problem.
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What model.year is the Punto?
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Hi.
I had exactly this problem with my pug 406 2.1TD
My pug garage eventually said (after much investigation and therefore cost)they changed one of the thermister valves,(i think that is what it was called, sorry I don't have bill with me )this fixed problem.
I am not very technical i'm afraid but apparently they have to run within a narrow temperature range or they send misleading info to the fuel pump.
I don't if your car has them but hope this might help.
gsb
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Attached directly to the accelerator pedal and "fly by wire" I follow. Can it not also sit at the end of a standard bowden cable link and still fulfil the role of converting movement to an electrical signal for the emu?
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Indeed it can.
number_cruncher
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B'naut - many Peugeots have their thr-pots at the end of several feet of 'bowden cable' - my 306 has, anyway. The pot itself is just behind the bonnet lock at the front of the car.
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