Low Rev Throttle Response, at a loss now!

tweedandbriar said:

Would a faulty Crank Sensor have the same effect?

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I'd bow to others experience to the contrary, but unless it's a broken wire they either work or not.

tweedandbriar said:

Carbon pot?

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Potentiometer. I'd assumed the pedal relied on a rotary counter, but if @tottot mentioned pots.

Edit. And they come in two main flavours, wire wound and graphite/carbon. Guess which is more reliable and expensive?

Part of the throttle pedal body

boguing said:

Potentiometer. I'd assumed the pedal relied on a rotary counter, but if @tottot mentioned pots.

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Ah yes, they are pretty hard to source for less than a couple of hundred squid!

I also tried 'resetting' the throttle by turning ignition on and pressing the pedal 5 x quickly - the engine light flashed, and then I started it up. Seemed a little better. The engine light only flashed once and at the same point after the fifth press.... I hear that can reset the ECU in that respect(?)

tweedandbriar said:

Ah yes, they are pretty hard to source for less than a couple of hundred squid!

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I had to scrap a perfectly good car because Citroen had decided it was cool to design their own potentiometer for the throttle body than to find a way to use a 20p one off the shelf. Replacement of the whole thing was £400.

@Anaconda mentioned that you should be able to see the throttle operation in the diagnostics. If yours does show it then you're looking for a straight line on the graph. If there are any spikes you may have found a problem.

Got one of these ... do you think its worth trying this before a whole loom?

If it were me I'd be exhausting the diagnostics before trying part swaps.

As I said above, if you can watch the output, then do it. Move the pedal through its range. If no spikes then wiggle wires thoroughly to check for spikes caused by a break or poor contact. If nothing happens with either AND the range of outputs meets the spec then there may well be nothing wrong with it.

Thanks, I'll get the Nanocom on it later and put the files up.....

You can buy an over lay loom which goes from the pedal to the ecu. This will bypass any problems in the original loom, cheaper than a new pedal, if you can get them

As you said it’s fine when warm, are you getting a reading from the coolant temp sensor, as it’s probably used in the fuelling strategy

tweedandbriar said:

Thanks, I'll get the Nanocom on it later and put the files up.....

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Hi, so with my limited understanding of the Nanocom (only had it a couple of days) here's the readout from a drive a couple of hours ago - can you guys help me interpret any potential problems?

Nanocom Readout

Thanks!!

Was that logging while you were driving? (Or, what was making the revs go up and down?).

Was you driving it when logging as air flow values are low.

Throttle pedal values look ok to me.

johnlad said:

Was you driving it when logging as air flow values are low.

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Yes, when driving, only for a mile or so.

It is a lot better. Not sure if that's because the engine was warmed up or because it's so bloody hot today! Feels like there is a little fine adjustment to make somewhere as still prone to be aggressive from a standing start and DEFINITELY doesn't like low revs in 2nd gear...that's when she wants to start 'hopping'

Unplug the Maf sensor and take it for a spirited drive.

johnlad said:

Unplug the Maf sensor and take it for a spirited drive.

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Ha! Like that "spirited drive" ...what are you thinking?