Guess what, snow and no Low range.....

[MuckyPup]

Hi Folks, sorry I've not been around in a while, setting up a new business.
But can someone help me with this please ?

Select Low range, 5 seconds later engine cuts out dead.
Restart engine
Drive in Low and as soon as RPM rises to maybe 2000 it cuts out DEAD.
Something seems to be electrically wrong, it cuts DEAD.
Any ideas ?

 

[grantw]

Diesel or Petrol? ... i'm sure that is the first person from some one who may have a suggestion will ask.

 

[Roger Fairclough]

Does it drive normally in high range?

Roger

 

[MuckyPup]

Diesel UK spec 4.2 turbo / ABS
Drives perfectly normally in high range / ticks over perfectly normally in Low range
The only abnormally with it is it won't start if you turn the key straight away, you have to turn the ignition on and wait for the dash lights / relays etc to "boot up" and THEN start it. I only mention this because it didn't used to do it.......

Select Low range, ABS light comes on, Diff light comes on, engine dies.
Restart, abs light on, diff light on, ticks over fine. seems to drive in first slowly, seems to reverse slowly but as soon as rpm / maybe boost rises engine cuts DEAD.
Just noticed the overboost light flickers when it dies, not comes on, just flickers.

I'm a mechanic and this has got me mystified. A short somewhere ? A protection system ? Bloody odd.

 

[warrenpfo]

Any codes stored in the ecu?

 

[Roger Fairclough]

Sounds like a short somewhere. This cold wet weather could have started the problem somewhere.

Roger

 

[Jon Wildsmith]

what year? Check battery to engine earth leads, sounds like a bad earth or similar. The only thing that will stop the engine running is lack of power to the fuel shut off solenoid. On a 12 valve it's fed from the ignition switch, maybe via an imobiliser if you have one. On a late 24 valve it's fed from the engine ECU and depending on year the engine ECU may talk to the transponder ECU so it's a bit more complicated. It would make it easier to help if your signature had your truck details

 

[MuckyPup]

power to the fuel shut off solenoid. On a 12 valve it's fed from the ignition switch, maybe via an immobiliser if you have one.

Aha.... We seem to have had some elctrobodgery on this truck to bypass a defunct immobiliser. Some delicate technical bodgery (I used insulation tape not Selotape) later and we have functional low range.
(Gave it a hot wire from the aux power take off box to the pump solenoid)

Looks like I'm going to have to trace and remove whatever lurks behind the dash, can't be good.

Thanks everyone.