Charcoal Canister: Disable on LPG?

[CitroJim]

A member of another forum I frequent has a problem where his LPG-converted XM (mixer rather than sequential) will no longer start or run on petrol. He normally starts up on LPG and he's not run it on petrol since March...

I suspect it's just simply a case of stale petrol.

However, I got to thinking. I'm pretty sure the charcoal canister continues to purge at regular intervals when running on LPG and I was wondering if this constant purging of the petrol tank of its vapours has effectively purged away all the light volatiles in it and basically rendered it useless.

Should perhaps, the charcoal canister purge be disabled when running on LPG?

Only issue is that straight disconnection of the purge electrovalve on Citroen ECUs brings up a fault.

Thoughts?

[rossko]

I think you'd lose the volatiles whether you scoop them up in the cannister or not. It seems to be a truism that modern petrol goes off after a few months, whether LPG is involved or not.

Other causes of no-go - gummed injectors, float valves, pump or pump valves etc. from disuse

[mat_fenwick]

I wouldn't have thought that age alone would make it impossible to start - based purely on the fact that my Discovery has been sat in the workshop since (coincidentally!) March whilst waiting for a replacement windscreen. It took me a good while to get around to sorting out the rust underneath it, and now the new screen is in it started and ran on petrol with no problems.

Is the XM in question carb or injection? - I remember the early 2 litre models were available with a carb. As Ross says, I've known float valves stick after even a couple of months.

Oh, and welcome along Jim - fancy seeing you here

[CitroJim]

Thanks both The XM in question I believe is a 2.0 Injection.

So, petrol goes off that quickly then? Gosh I must run mine on petrol for a bit. Never put any in since I've had the car and the tank is half-full - which on an XM is a LOT of petrol. I'll cry if it goes off

Oh, and welcome along Jim - fancy seeing you here

Hi Mat Good to see you, thanks!! How many other mutual friends lurk in these parts I wonder?

I'm here because all sanity and reason went straight out of the window a few months back and I finally gave in and got an XM It happened to be already LPG'd which was a major consideration when making my choice and I'm loving the economy of it.

Delighted with it actually. A real lazy, comfy cruiser and just flew through it's MOT

[moorsman]

hi its that v6 you should get on gas bet thats a lovely mover regards kev

[mat_fenwick]

The XM in question I believe is a 2.0 Injection.

I'd check for fuel pressure at the rail then, and then maybe make up/buy a noid light to check for injection pulses. I made one up with two (different coloured) LEDs wired with opposite polarity, so however the injector is triggered it will light up. I can post you a plug if you like? If pressure and pulses are both present then it must be stale fuel.

How many other mutual friends lurk in these parts I wonder?

I know Mike E has been on here...anybody else?

[CitroJim]

hi its that v6 you should get on gas bet thats a lovely mover regards kev

Yes, it's tempting Kev but the fact is the V6 is more frugal than the two turbos are (both the XM and Activa has the same engine) by a long margin..

The V6 moves a treat and has a lovely Jekyll and Hyde character about it; it is happy to just potter when you want or when you grow a pair of little horns and a pointed tail it goes like a scalded cat, especially if you hit the Sport button

I did, for a short while, have an XM V6 (same engine as the Xantia V6) with a very scruffy LPG install on it. That moved on to someone more capable of doing the work needed than I and whilst it was under repair the LPG ECU became full of water and was ruined; the owner is after another. I believe it might be an ABK or some such obscurity... He's having a lot of bother finding one.

The problem with LPG'ing a Xantia V6 is there is precious little room under the bonnet to mount the vapouriser in a sensible (or even stupid) place.

Mat, I really must build myself a NOID light. The person experiencing difficulty with his XM is in Romania and sadly not very local to me or it would have been sorted by now. He's convinced the injectors have seized up through lack of use...

Thanks for the very concise tips Mat, I shall pass them across

[bxman]

Hi Jim

good to see you here again.

I hope you friend has kept enough petrol in the tank .

If not the pump burns out through lack of lubrication. it runs continuously regardless of fuel type in use.

Never investigated if you can switch of the 12v to the pump it suspect you can.

But I believe the petrol injectors can overheat if there is no petrol circulating.

So best to keep a couple of gallons in the tank at all times.

best wishes to all on fcf , must look in again sometime soon.
cheers Patrick

[CitroJim]

Hi Patrick

Good to see you on here and that you're keeping well

Long time no see on the FCF!

The XM in question is a long and somewhat torturous story If you are a member of Club-XM.co.uk you can read all about it
I think you may need to be a member to read that thread though...

[E46CoupeM3]

I think you'd lose the volatiles whether you scoop them up in the cannister or not. It seems to be a truism that modern petrol goes off after a few months, whether LPG is involved or not.

And yet my old Opel Manta that has been off the road 4 years still starts on the few litres of fuel left in the bottom of the tank