Mud-club

Vehicle & Technical => Discovery => Topic started by: ne jones on November 24, 2006, 17:00:30

Title: LPG anti backfire flap
Post by: ne jones on November 24, 2006, 17:00:30: where can i buy one of these from?

my dads lpg 200mpi has destroyed the airbox because of a backfire and reading through various posts it seems he needs one before even more damage occurs.
Title: LPG anti backfire flap
Post by: blackbob on November 24, 2006, 17:30:19: sounds like a build up off gas on over run best to get the settings checked also check for power drain ie cb ect cos it can effect the gas vaporisor unit
Title: LPG anti backfire flap
Post by: bilge rat on November 24, 2006, 18:01:35: heard of this before, i do know they fitted it to some porsche,s as they had a problem the same but on normal fuel, cheaper than replacing the air box. try a few porsche sites see iff ya can find anything. just a thought . alan......
Title: LPG anti backfire flap
Post by: Range Rover Blues on November 24, 2006, 19:06:55: They were fitted a lot ot 3.5 EFi RRC because of the flapper VAF sensor, they explode when the car backfires. You can buy them from LPG installers, I think OMVL make them amongst others. They tend to be less common these days as the Hot Wire EFi uses a MAF sensor that has no moving parts.

Backfires can also destoy brake servos and hoses, go on, ask me kow I know :roll:
Title: LPG anti backfire flap
Post by: bilge rat on November 24, 2006, 20:37:09: i bet that went with a heck of a bang. .alan.....
Title: LPG anti backfire flap
Post by: jjsaul on November 24, 2006, 21:14:39: leave the pipe from AFM to plenum chamber loose....
Title: LPG anti backfire flap
Post by: hairyasswelder on November 24, 2006, 22:38:59: Quote from: "jjsaul"
leave the pipe from AFM to plenum chamber loose....

Only if you want to get out the car on the motorway after it has blown the pipes off :cry:
If you do loosen them tie them with a tie wrap or similar so you dont loose them when they blow off :wink:
on 3.5 the AFM controls the fuel pump so you cant use petrol and with no pipe you cant draw gas :(
Buy a backfire protector, try searching 'tinley-tech' some people swear by them. mine came off e-bay
Been there-done that and looking for pipes on a busy dual carraigeway is no fun :oops:
Steve
Title: LPG anti backfire flap
Post by: jjsaul on November 25, 2006, 01:18:37: Quote from: "hairyasswelder"
Quote from: "jjsaul"
leave the pipe from AFM to plenum chamber loose....

Only if you want to get out the car on the motorway after it has blown the pipes off :cry:
If you do loosen them tie them with a tie wrap or similar so you dont loose them when they blow off :wink:
on 3.5 the AFM controls the fuel pump so you cant use petrol and with no pipe you cant draw gas :(
Buy a backfire protector, try searching 'tinley-tech' some people swear by them. mine came off e-bay
Been there-done that and looking for pipes on a busy dual carraigeway is no fun :oops:
Steve

It shouldnt be blowing pipes off on dual carriageways or its all set up wrong..only time mine blows the pipe off is under load on steep hills. So basically on v steep tarmac or offroad when you bury the throttle...
Title: LPG anti backfire flap
Post by: Range Rover Blues on November 25, 2006, 01:30:38: When our on a draw through backfires it's because it's done a valve. I had it backfire on the M1 once though, coming up the hill from Megahell :roll:

I built my own in the end, 2 plates of 3mm steel, couple of short lengths of piep the right size and the shoe retaining springs from a Cortina to hold is all together. Valve grinding paste to lapp the halves together, the partial vacuum keeps things airtight.
Title: LPG anti backfire flap
Post by: ne jones on November 25, 2006, 09:21:09: Thanks for the advice. We've located an ebayer that supplies the part recommended so dads gonna try him first.
Title: LPG anti backfire flap
Post by: Ogbyte on November 25, 2006, 19:10:01: Hi Ultra Hunter,

Can you PM me a link to the ebayer info, or post here for those interested - we could do with two of these for our LPG powered beasties.

Have already mangled a MAF meter on one due to a blowback because of trying to accelerate up hill and didn't realise LPG was empty.

cheers
Gary
Title: LPG anti backfire flap
Post by: ne jones on November 25, 2006, 19:57:18: http://cgi.ebay.co.uk/LPG-MIXER-FOR-LANDROVER-RANGEROVER-3-9-EFI_W0QQitemZ220050903811QQihZ012QQcategoryZ9895QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

READ THE DESCRIPTION
Title: LPG anti backfire flap
Post by: Range Rover Blues on November 25, 2006, 22:53:14: Funny that ogbyte, now when mine runs out it just stumbles, I have heard they backfire when near empty but ours doesn't.

The multipoint on the lSE is best though, it just flips you back onto petrol and beeps, hardly any loss in progress at all.
Title: LPG anti backfire flap
Post by: Range Rover Blues on November 25, 2006, 22:54:36: BTW that's not a very good mixer, just look at the rstriction in the air flow. A draw through system needs that restiction but a single point might not neccesarily need it.
Title: LPG anti backfire flap
Post by: jjsaul on November 25, 2006, 23:39:06: i'll withdraw my previous comments...sods law aint it...now looking for a new AFM :roll:
Title: LPG anti backfire flap
Post by: hairyasswelder on November 26, 2006, 11:37:53: Quote from: "jjsaul"
i'll withdraw my previous comments...sods law aint it...now looking for a new AFM :roll:

You were 1/2 way to the truth, It was set up a bit poor. It did it on kickdown (auto) overtaking a lorry on A38. left me coasting to the side of the road :oops: good job it was a rangie so i could stop on the grass verge :cry:
Have changed the evaporator and afm and am changing the engine now as it is getting tired and needs some lovin'
Always looking onn e-bay for afm as i keep a spare or just buy them if they are cheap :)
Steve