V40 Bi-Fuel Advice needed please

[Slapaduma]

Hi all... I have just joined this forum with the idea of getting some help. I have recently bought a V40 bi-fule and whislt i am very happy with the car when running on petrol there seems to be a almost constant missfire when running in LPG. If i leave her ticking over in LPG she's fine but as soon as i move off at low speeds in comes the missfire. Its almost as though the air-flow through the engine bay is causing the problem?
It's cured by immediately switching back to petrol.... this missfire is prevelant all the way up the speed range but decreasing slightly as the speed goes above 60mph.
Can anyone help please.

Slapaduma The well know anagram

[kevin derby uk]

advice on LPG is very rair indeed and even worse with CNG. good look.

[jiffy176]

This is probably down to a dirty distributor on the LPG system.
Real easy to fix. Find the LPG distributor it is bolted to the bulk head and has Necam Koltec written on it.

Disconnect electricl switch, undo both screws and slowly lift the stepper motor off and piston. slide off the O ring from the steper and remove spring.

Now inside you will see a cylinder with 4 or 6 ( not Sure) V grooves in, these get full of you know what. Basically what happens is gas goes into bottom of this and asyou put your foot down and call for gas the stepper motor lifts the piston which lets the gas out of the V grooves down the lines into the cylinders

You can use a tool to get in the two holes to slide it out but the cyclinder is stiff. I am lucky and my thums fits nicely and with about 4 or five goes I can wiggle it out. You need to change all the Orings and clean the V grroves out.
If you scratch the cylinder getting it out forget putting it back in it will leak. Google Necam Koltec ans V40 on ebay and lookf for a dutch gye called Kees he sells replacements.

Google Nicholson Mclaren in Wokingham Berks they do replacement O rings. £4 ish

Replace all o rings make sure the spring sits in correctly put it all back together and see what happens, might die first time onto gas no problem try again, if it keeps dying then you haven't fitted the spring corectly

If it all runs correctly get a squirty bottle like you get windowleen in fill with soapy water and spray on the assembled unit when running on gas, that way you know if there are any leaks.
Good luck