VS Stalling when running on LPG

[nathanshnoz]

Hey all,

Having some problems with my VS. I went overseas and my sister was driving it and said that it backfired and then wouldn't start afterwards. I got back last week and found the air bell (on the gas mixer) was busted so replaced it and still nothing. Couldn't hear the fuel pump and it had spark so i replaced the fuel pump and now it will start and run on PETROL but when you switch it to gas if you let the revs drop below about 1,000 it just stalls. It does not stall on petrol only on gas. I ran engine diagnostic and it threw a few codes, most seemed trivial except throttle position sensor so i replaced it with a new one and i still have the same problem.

Any help would be much appreciated, otherwise i'll have to bite the bullet and send it to a gas specialist

i know there is a lot of threads about gas stuff on here but i can't find the answer anywhere.

Cheers

[strgas]

Air bell metal or plastic one ? model of mixer would help too impco 200 ???

[nathanshnoz]

air bell is plastic.

it's an L.G Motor Gas 225 mixer

[strgas]

ok know the mixer well , sounds like the mixer diaphragm is stuck or bent out of shape , remove the bell and check the screws around the top of the mixer are tight , if tight remove the 5 screws and check the diaphragm and air valve is intact , check the 4/5 screws on the top of the diaphragm are tight , next look into the mixer valve see if theres anything loose or broken pay attention to the centre of the valve these often crack or come loose or deform from back firing.

[hsv304v8]

do u know its illegal to touch it without a gas licence.

[strgas]

do u know its illegal to touch it without a gas licence.

If your referring to the high pressure side then yes it is . Im yet to see or hear of anyone getting stung for this

[nathanshnoz]

hey mate i opened her up and had a look, couldn't see any damage inside and the diaphram was still moving fine and could not see any damage to it.

i spoke to a gas mechanic today and he seemed to think it would be the gas converter that might be the problem?

[strgas]

could be related to the convertor , hard to say without having a look

[nathanshnoz]

ok mate, thanks for the help, i might just have to get a gas place to look at it i think

[nscheg]

May be totally off here, but check your coolant level - if there's not enough coolant in the radiator, the converter will freeze up.

[nathanshnoz]

hey guys,

turned out to be a small misfire caused by worn leads.

new leads and plugs and away she goes! good lesson learnt here, and that is worn spark plugs and leads can cause your gas to stop working completely. i knew there was a smaller tollerance with plugs and leads for gas to run than for petrol but didn't realise how small the tollerance for gas actually is.

Thanks everyone for your input

[xcop]

i was having having bad back fire problems, stalling, after getting sick of replacing airboxs, replace diaphram an put a shim in it, replace plugs an leads this will stop it 100 percent