Hi all we have diagnosed a weird issue - if the lpg kit is connectors permanently to the obd wire after the car starts up and get to warm (a few minutes) the temperature drops to one quarter in the cold and the fan goes full speed and sounds like an old plane! If I pull over turn it off and on again all is good in the world. Cut the lpg obd wire and all is good in the world. It’s an aeb/king setup and is working ok without the connection but would like it if someone can think of a fix?

Any ideas? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

IIRC the wire was just to cancel any faults every time you switched on, or off, either that or reset the fuel trims...

If the LPG is set up correctly you shouldn't need it.. Pete

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Try running a fault scan when it next does it with the wire reconnected.
I've seen it before and p0116 is usually the culprit.

Haylands-

The fitter said it can do real time trimming now longs it’s not too far out.

Dingg- yes that is the fault but I have changed both sensors (too and bottom) and the stat made not difference how did you fix? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Right, mine used to do that on occasion and all I'd do was the same as you switch off and restart would sort it 9 times out of ten.Sometimes it would take 2 shutdowns to get back to normal.

Since having a new alternator and waterpump fitted in January it hasn't happened once, I really don't know what would cause it to stop happening, but possibly the coolant change and the reconnected associated electric fan connection maybe first port of call.

Good luck

Ps your diagnosis is probably a bit off too.
It happens as soon as you start the engine ie the code is set and your fan starts running as it has an incorrect signal from the ect as time goes on and that signal doesn't change the fan runs harder and harder then you see the temp not increasing and notice the roar of the fan.
It can upset your fuel trims slightly too as the engine ecu sees a hot engine and adjusts the fuelling to suit.

dingg1 - two things - I changed the alternator etc recently and it made no difference although not done the water pump as not needed to.

Maybe we had different issues as my diagnosis re the temp gauge is 100% accurate starts cold goes to the middle and then it slowly comes down to 1/4... Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

I didn't suggest that you needed to change the water pump or alternator, it just so happens that after that work was done on mine the issue has never came back.

So at that same time the coolant was drained and refilled and the electrical connection to the fan would have been removed and reconnected, that's where I would be looking as first measure of investigation.

ok but if I disconnect the gas from obd I have no issues? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

I never did disconnected the lpg system it still is tied into the wiring behind the obd socket

Just to complete this thread someone else on here fixed it with an lpg ecu firmware update on an emer system but no other aeb ecus got said update.

What we did to fix it is to put the obd link connect on a relay when the gas switches over. Caused no issues and works fine now Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF