Electrical issues

[Bilbat]

Hi All. One for you to think about. I have a 2005 Fiat Ducato 2.8JTD motorhome which started doing strange things electrically. It started with when driving along and switching the lights on, the engine loses power but if you push the throttle to the floor, it picks up again and runs fine. Three weeks ago while driving early morning to a site in Wales I applied main beam and the radio switched off, change back to dipped beam and the radio came back on. The temerature guage instead of showing a steady normal temp acted a bit like a rev counter, going up when applying power and coming down when not. I have been advised that all of these problems are down to a bad earth on the engine. I have added 2 extra earth straps from the engine to the body and all but one of the faults have gone away. The engine still loses power when I switch the lights on and picks up again when I push the throttle to the floor.
Sorry the description is so long but I wanted to give the whole story.
Anybody got any ideas?
Martin

 

[Figaro]

You have a poltergeist, exorsisim needed at earliest opportunity.
Seriously, no idea, never heard of those symptoms before.

 

[Clivefog]

First step get an obd reader plugged in and see if that gives a clue.
I would suspect a bad earth with the instrument cluster but that would not affect the engine unless an ecu is getting the wrong message?

 

[tonyidle]

First check the engine earth strap (gearbox end IIRC). The strap will look OK but they corrode within the crimped ends.

 

[Bilbat]

Is the gearox earth strap underneath / behind the air filter?