3.9EFI running problem.

[Jim-Willy]

Hi, I am having issues with my 110, it has a 3.9EFi and auto box out of a Range Rover.  It starts on petrol and lpg but once you set off and come off the accelerator to pull up at a junction etc it stalls and is then difficult to restart and won't idle when it finally restarts, if you are on a straight road and can drive without lifting off the accelarator it will eventually be ok and will run happily.  Any ideas as to what this could cause this?  This is my first EFI V8 and has run ok for the last 3 months and has just started doing this...  Cheers in advance.

[Range Rover Blues]

Sticky idle by=pass valve, it's on the back of the plenum.  Try cleaning with carb cleaner or WD40, otherwise it's a new one.

[dod51e]

Is this problem on LPG or Petrol?  If it is from cold the switch over to LPG could be too early as the vapouriser is still too cold and/or incorrectly set.
If just on petrol then I would second the above as a prime cause followed by a duff temperature sensor (not the one that goes to the dash).

[Jim-Willy]

Both petrol and gas, i'll check out the bypass valve at the weekend, cheers.

[Rossko]

EFI ECU also looks for a signal from the autobox selector, so it can lift the idle a bit to compensate for box drag.  Could be a wiring problem (missed in the conversion?) or PN switch

[Jim-Willy]

Seems RRB was right, cleaned the valve and it worked for a few hours then the fault reoccurred, hit the valve and it improved so a new one is required.  It has a new fault now, no power to the fuel  pump, a large brown wire to the relay which should i think be a permanent live isn't, trying to trace why is proving problematic.  Damned electrickery!

[Range Rover Blues]