Throttle Potentiometer Manual Recalibration

[Emmdat]

Still trying to track down my previously stated running problem. Having carried out various checks and investigations I have concluded that the part now potentially causing the problem is the throttle pot.

Interestingly, I came across the following recommendation as to how to manually reset the thing that was said to potentially give temporary relief for a failing part that would certainly get me through this upcoming weekend trip away. It says that it is for MEMS Equipped cars which is not something I recognise or have come across. Can anyone enlighten me as to what this MEMS is? Will this manual recalculation work on a 400 SE? I enclose the recommended recalibration method below,

1. With the engine off, insert the key and turn the ignition to position 2 (On)
without starting the engine.
2. For MEMS-equipped cars (S1), quickly press and release the accelerator pedal
several times (at least 5, but to be sure 8 or 9) using as much of the throttle
travel as practicable. This will trigger the ECU into the closed-throttle
reference learn algorithm, which has it looking for the lowest measured static
throttle position (the closed position). The throttle position calibration is a
fixed definition from this point.
3. Turn the ignition off, remove the key and wait for the ECU to power down (about
30-40s).
4. Start car as normal.

[rev-erend]

I've not heard of MEMS .. the very latest Range rovers using the RV8 had GEMS.


There is no reset method for our throttle pot.

If you have a volt meter it's easy to check the throttle pot ..

there are 3 wires

1) 5v reference
2) earth
3) 0.3v ~ 4.5v depending on throttle position
0.3 volts should be at tickover ..

Do test with ingition on but without engine running..

As you move the throttle - the volt values should steadily rise .. no big jumps or getting stuck - if it does then you either need a new one of perhaps Adam Quantrill can fix yours ?


They are still available new and second hand .. I bought one on ebay used for £5

New (Classic Range rover)
FF001304 £89 and FF001305 £145
http://www.famousfour.co.uk/new_parts/parts-veh-rr...

[CarbonWedge]

MEMS is a much later engine managment system, not used on Wedges unfortuntely, I don't know if it's used on any of the range rover v8s, but my missus K series MGF has it.

[Emmdat]

Thanks Guys, I thought it might be too good to be true. I'll check it more carefully with the meter tonight but either way it looks as though it's going to be a weekend away with an annoying fault!

[rev-erend]

Just make sure at 0 revs it's set at 0.3v ~ 0.32v..