Diagnosing throttle pot?

[dnb]

What should the resistances be on fully open and fully closed throttle? And where do each of the 3 wires go...

I think mine's finally given up :( as the Griff let me down today.

Thanks!

[Ballistic Banana]

With ignition on You should get 33mv when closed slowly rising as you open the throttle to 4.5volts.
Think mine was across the Green and Blue wire, although from my understanding that can be different(the colour of wires)
If you do a search I am sure I asked about these on a thread before when setting mine up.

BB

[GreenV8S]

Disconnect it, it'll run without it (albeit with rubbish throttle response), if it doesn't run now then that wasn't the problem.

(I thought the threshold for zero throttle was 300 mV but too lazy to check now ... )

[dnb]

The car runs fine for most of the time.

But for reasons only it knows, it just stops sometimes. Usually with an impeccable sense of comic timing

[rat]

To compare with spec you have to measure voltages by t-pinning the connector with ignition on, but engine not running. Should read 290+/-20mV or 325+/-35mV depending which throttle pot you have (290-310 is OK for both but very hard to get into this narrow range). 4.6-5V full throttle. According to the bible (as I recall, because it's not to hand) >4.6V is important or you'll get pinking on full throttle.

Presumably quoted in Voltage because signal to ECU is what counts, and that depends on input voltage+resistance of throttle pot.

If you don't have the right connectors to make a bridge, stick strong pins through the wires to get a reading, but do that a few inches apart and be careful they don't touch each other or any earth point.

[dnb]

Thanks all.

The Griff ran fine to work this morning (it's the only car I have at the moment, but that's another story), but I was very careful with the throttle.

Will check the sensor at lunch time if it's not raining.

[shpub]

Also bear in mind that testing with a voiltmeter will only prove that the pot is faulty and not that it is OK. A lot of throttle pot problems are caused by noise which you can't see with a multimeter.

[dnb]

I should be getting my hands on some proper diagnostics tools tomorrow...