Hi All,

I am getting very poor very quickly... and losing a lot of hair fast...

For around 3 weeks the lpg on my car has not been working right... it started off with what seemed like a vibration from the rear... I thought it was the TC on its way out and although annoyed just drove for a few days...

We then had the engine light flashing (not staying on) and they car ran very very lumpy... You could drive through it (the wife was in it she told me she just carried on) and it went ok. I then have been driving on petrol for the last 2 weeks until my lpg man could take a look.

Well the problem seemed a lot worse... when you switched at idle it now just dies slowly.

We tried switching off every injector for diagnostics and having it on 'lpg' it ran fine (all injectors on petrol) however switching any one injector to LPG we tried all it starting to run really rough not enough to kill it but it wasn't right.

It has had a new Ecu in the last 8months and injectors and pipework as it was all getting brittle. The only thing that wasn't new was the vaporiser. We just changed that and its still the same and I'm not too impressed

Any ideas what could be my gremlin?

Oh and we tried recalibrating but it wouldn't even do that without dying. Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Has it run empty? If you run out of gas you can get all the S*** clogging everything up.

nope not at all it had 1/2 a tank and I filled her up elsewhere also filters changed... Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

How fresh are the spark plugs, coilpacks, ht leads? LPG is harder to ignite than petrol.

Plugs are under 10k - no ht leads as they have coils straight on them which work fine - I'd get it for these components if it was a couple but not all and not just suddenly rather than slowly degrading... Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

If the car runs fine on petrol best thing to do would be get the LPG ecu hooked up see what faults it has seen

LPG Filter? these need changing regularly and start to fill with a white liquid (like tippex) if not changed every 200 hrs or yearly.

That was changed when we did the piping so that's ok - interesting you say that - in my m6 I did 40000 miles on one changed it cut it open and it still looked near new... Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

The front O2 sensors would be a good place to start. sounds like the engine is running too rich on lpg. Then remap the lpg ecu. The fuel trims are too far out for the car to run properly on Lpg and although the car proberbly runs ok on petrol your Mpg is pants 5.0 supercharged autobiography
Gone-4.4 Vogue Lpg now unmapped
4.6 HSET Turbo Lpg mapped
Gone-Defender 90 200tdi
Gone - 3.9 Sprintex supercharged LPG
Gone - 3.9 Vogue LPG

It's actually running lean all the faults it throws when on gas say lean bank 1 , 2 etc. Not getting any o2 sensor faults though except one rear o2 heater which has been like it since I had it and it ran fine as I think that's just for emissions Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Then it stands to reason that your fuel map is incorrect on the lpg ecu.
just remap it. 5.0 supercharged autobiography
Gone-4.4 Vogue Lpg now unmapped
4.6 HSET Turbo Lpg mapped
Gone-Defender 90 200tdi
Gone - 3.9 Sprintex supercharged LPG
Gone - 3.9 Vogue LPG

You say you've changed the reducer , have you set it up to exactly the same pressure , as above sounds like it needs calibrating to me , can be a long job to get right if you don't know what you're doing

Just read your post hope you got it sorted .Had same problem with mine changed vaporizer had to up pressure.Found a very knowledgeable mechanic in Edinburgh who pointed out that my vaporizer {the magic one} was set to high up the wing and if there was any air in coolant system an air lock would cause lpg system to run all over the place .As the pipe work was above the expansion bottle it was very hard to bleed { makes sense} I made a simple bracket to lower vaporizer and have had no problems since .Hope this helps

Yes I went same path but ended up being clogged injectors! Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF