XSeries-forum

They say your problems come in three’s, should I be greatfull that they happened over a two day period. LPG system wouldn’t switch over then died completely. AFM packed up, car died if brought to idle. Heater valves, one stopped working the other won’t open till above 28c.
AFM, easy fix, fitted new Bosch, sorted. Water valves on order. LPG, nightmare. There isn’t anyone within a 100 miles who has diagnostics or will even look at it. Having read about them having gumming up injectors broken diaphragms and such and the fact that I have nothing to loose as it wasn’t working. It was time for a crash course. The system was fitted in 2005 by a BMW dealer in Glasgow.. It has 2 mixers/reducers KME It.has HANA injectors and three filters.and an ECU with a diagnostics port.
Found the lack of power as a bad connection in the relay box. Now have a flashing red and blue light on the start button but no green lights to indicate gas level. Tank is full. There are 4 solenoids, none are operating.
Because it is 16 years old I decided to strip everything down and clean/inspect. Reducers, basically a box with a wall in the centre, coolant flows through one side of it to heat up the gas which flow through the other side. There is a rubber gasket on the coolant side to stop leaks and was in excellent condition. There is a port for a temperature sensor. The gas side has a diaphragm which has a nozzle to connect to the vehicle vacuum line. This was also in pristine condition with no gummy substance as reported elsewhere. All 8 injectors were removed and although not bad there was some grot in there as when cleaned with carb cleaner you could look down the tube and see a gauze filter (that’s what it looks like) The injectors are attached to a rail and have "o’ rings to seal them. At this stage everything is very clean but still not working. So over a nice cuppa I’m trying to think how or what switches the solenoids on to let the gas through. Well of course the ECU does it but what tells the ECU to do it. Obviously it’s the bloody temperature sensor. Theory of course. So I bared the wires 2 on the temperature sensor joined them together and all 4 solenoids click. The red flashing light has gone out and the green level lights have come on. Switch the gas off and solenoids go off, likewise switch ignition off the ignition and solenoids go off. Only problem with this system is that you must remember to switch the gas off at the end of a journey otherwise you will be trying to start a cold engine on gas. Checked for leaks but really if you have one you can smell it, went for a drive and all is well. I have ordered a temperature sensor £12 so should be back to normal by next week.

Good bit of detective work

Good work, sometimes it's just old school fault finding, which is quite nice nowadays
Not many of these left out there, let alone lpg conversations that still work as they should.
My beast doesn't get used much nowadays and I often think it's a waste just sat there, but then you have chance to get out in it and it's just a nice place to be, not too slow either, lol.

My Range rover sport supercharged has lpg and I think the lpg temp sensor is on its way out. From a cold start it's OK after switching over to gas but after maybe 5 min the engine starts to hunt, the temp gauge drops down to nearly zero and the interior fans in the dash run erratically.
If I switch the motor off and back on everything is back to normal and continues to be until the next cold start.
I was going to send it to an lpg specialist for a service but I may just swap the temp sensor to see what happens.

Always good to get the lpg serviced regularly, and by someone who knows what they're doing.
No point in having a system fitted designed to save running costs if it's not performing as it should.
When they're operating correctly you'll hardly notice the difference, ( as you already know ), but become a pain when not running as they should.

Propper old school mechanicing ?.
Just a shame the technicians we have today don't have a clue what it is.

I used to take it to a Polish guy when I lived in Dorset, but as said there’s no one I can find in Cumbria. I do the filters every 5k so presumably that’s why the insides were so clean. The system is fairly simple but the ECU mapping is another matter. I might look into what sort of diagnostics one needs. Although the Polish guy always plugged in to diagnostics socket and always commented that they very rarely ever needed adjusting.
At the moment the temperature sensor reads 1.2 ohms whether at working temperature or cold. Presumably this should change with temperature to trigger the ECU to switch on the solenoids. We’ll see when the new one arrives.

Well done for logically thinking it through from first principles. Most ‘technicians’ these days would have reached for computer, found diagnostics wouldn’t work and offered you a complete new system…..

Finally got the sensor, £4.90 + post + tax = £12.80. All back to normal.

Yeah…