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[tgm147]

Getting close to torching it again!

It has now decided it doesn't want to behave on gas. It feels very down on power, almost splutters and eventually dies off completely to a really rough idle and won't maintain any form of speed. On petrol it's fine and pulls clean all the way to the redline. This has come on very quickly today, yesterday it was perfectly fine with no troubles at all. I'm at a loss now as to what it can be. In the last few weeks she's had:

Head skim and gasket.
New GM coilpack.
New GM cam sensor.
New GM thermostat.
New NGK spark plugs.

They all cover everything I can think of that would cause this.

Any ideas guys? Want to burn the oppsing thing.

[JamesV6CDX]

What LPG system?

Any warning lights?

Any fault codes in any of the ECUs? (petrol and gas)

If you need help with my last question, we can direct you to code reading methods

[tgm147]

Prinns VSi.
The EML is on and i'll plug it into the code reader tomorrow. I'm guessing it's going to be lean/rich exhaust and missfires on cylinders. Nothing abnormal on the LPG panel. Not going back to petrol on its own and no other lights on apart from the gas level gauge.

[Entwood]

Getting close to torching it again!

It has now decided it doesn't want to behave on gas. It feels very down on power, almost splutters and eventually dies off completely to a really rough idle and won't maintain any form of speed. On petrol it's fine and pulls clean all the way to the redline. This has come on very quickly today, yesterday it was perfectly fine with no troubles at all. I'm at a loss now as to what it can be. In the last few weeks she's had:

Head skim and gasket.
New GM coilpack.
New GM cam sensor.
New GM thermostat.
New NGK spark plugs.

They all cover everything I can think of that would cause this.

Any ideas guys? Want to burn the oppsing thing.

Drive it until it starts coughing on LPG, then feel the vapouriser if it is NOT hot then that might be the problem, as the liquid gas needs heat to vapourise ....

[tgm147]

Getting close to torching it again!

It has now decided it doesn't want to behave on gas. It feels very down on power, almost splutters and eventually dies off completely to a really rough idle and won't maintain any form of speed. On petrol it's fine and pulls clean all the way to the redline. This has come on very quickly today, yesterday it was perfectly fine with no troubles at all. I'm at a loss now as to what it can be. In the last few weeks she's had:

Head skim and gasket.
New GM coilpack.
New GM cam sensor.
New GM thermostat.
New NGK spark plugs.

They all cover everything I can think of that would cause this.

Any ideas guys? Want to burn the oppsing thing.

Drive it until it starts coughing on LPG, then feel the vapouriser if it is NOT hot then that might be the problem, as the liquid gas needs heat to vapourise ....

Will do. Believe the vapouriser is under the header tank but will follow the pipes and have a feel around tomorrow.

[Lazydocker]

Agreed... Classic symptoms of vap freezing And with that list of work there's a fair chance the coolant flow to it has been fiddled/airlocked

[tgm147]

Update time. The vapouriser is hot after a short run so I doubt its the problem. I have noticed a new noise though. Sounds like a pssh psssh psssh sound when under hard acceleration on gas but I can't smell anything. 

[Lazydocker]

Hmm... Completely clutching at straws but could be a vac pipe issue

If you've had the work done at a garage and it was fine before it went in (other issues aside) then take it back and get them to fix it FOC

[tgm147]

Hmm... Completely clutching at straws but could be a vac pipe issue

If you've had the work done at a garage and it was fine before it went in (other issues aside) then take it back and get them to fix it FOC

The head gasket was done by a garage but that was getting on for over a month ago and it's been perfectly fine since, just started playing up yesterday. I really am at a loss with this, been out and had it in bits as much as I can and can't see anything wrong, nothing lose or any weird bits of wiring. I've booked it into a LPG specialist next week and they're going to look over it because they install the Prins kits. With any luck it'll be a blocked filter or something simple like that. I've been through the rather big receipt book and can't find anything about the gas system being serviced, and it was installed over 70,000 miles ago.

[Kevin Wood]

Update time. The vapouriser is hot after a short run so I doubt its the problem. I have noticed a new noise though. Sounds like a pssh psssh psssh sound when under hard acceleration on gas but I can't smell anything. 

Is the tank getting cold and sweating / icing up?

[tgm147]

Update time. The vapouriser is hot after a short run so I doubt its the problem. I have noticed a new noise though. Sounds like a pssh psssh psssh sound when under hard acceleration on gas but I can't smell anything. 

Is the tank getting cold and sweating / icing up?

I haven't noticed but I'll go start it up and knock it onto gas and leave it to tick over for a while and report back.

[tgm147]

Just done a video of the car ticking over. It seems fine but there's a definite cough when revved. It only seems worse when under load, like it can't get enough gas through.

http://youtu.be/T2ST42t3UK8

The gas tank just felt normal, not oddly cold or anything out of the ordinary.

[Kevin Wood]

Update time. The vapouriser is hot after a short run so I doubt its the problem. I have noticed a new noise though. Sounds like a pssh psssh psssh sound when under hard acceleration on gas but I can't smell anything. 

Is the tank getting cold and sweating / icing up?

I haven't noticed but I'll go start it up and knock it onto gas and leave it to tick over for a while and report back.

You need to be pulling some serious gas out of it to notice, just thinking if it's drawing up vapour instead of liquid, as you drive the tank gets colder until it can't cope with the demand.

Given that work has been carried out on the front end, I'd say a problem with the tank is unlikely, but worth checking next time it's been on a longish run on LPG.

[tgm147]

Update time. The vapouriser is hot after a short run so I doubt its the problem. I have noticed a new noise though. Sounds like a pssh psssh psssh sound when under hard acceleration on gas but I can't smell anything. 

Is the tank getting cold and sweating / icing up?

I haven't noticed but I'll go start it up and knock it onto gas and leave it to tick over for a while and report back.

You need to be pulling some serious gas out of it to notice, just thinking if it's drawing up vapour instead of liquid, as you drive the tank gets colder until it can't cope with the demand.

Given that work has been carried out on the front end, I'd say a problem with the tank is unlikely, but worth checking next time it's been on a longish run on LPG.

That'll stump that one then, it won't run for long enough on LPG to do a run. I'm talking it packs up within a few seconds of switching from petrol.

[tgm147]

gone to pick a mate up from work, driven on petrol. The car is coughing a bit. Not ticking over smooth. Possible vacuum issue? Can feel the car shake and jolt. Normally dead smooth.