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From: jim holland on 17 May 2008 15:16
Hi All
I have ford Galaxy 2.3 1999 its LPG/Petrol the system is a single point
emmegas, when pulling away from standing start on LPG if the engine labours
or I try and accelarate to fast it backfires but if i'm a bit more gentler
on acceleration its ok when it gets going its fine taken it on motorway it
drives great has anyone any idea what causes the backfire and how to stop it?

cheers

url:http://myreader.co.uk/gp/1272-1.aspx
From: Dave Griffs on 18 May 2008 16:37

"jim holland" <gordi(a)talktalk.net> wrote in message
news:345cb808edc24accbb58f4f211f0ecf6(a)newspe.com...
> Hi All
> I have ford Galaxy 2.3 1999 its LPG/Petrol the system is a single point
> emmegas, when pulling away from standing start on LPG if the engine
> labours
> or I try and accelarate to fast it backfires but if i'm a bit more gentler
> on acceleration its ok when it gets going its fine taken it on motorway it
> drives great has anyone any idea what causes the backfire and how to stop
> it?
>
> cheers
>
> url:http://myreader.co.uk/gp/1272-1.aspx

Could be a weekness in the ignition system, changing plugs and leads may
cure the problem. Emmegas systems aren't the best unfortunately, my previous
car had the same system, & even with new plugs and leads, it was still prone
to the odd backfire.

From: entwisi on 18 May 2008 16:43
On Sun, 18 May 2008 21:37:58 +0100, Dave Griffs wrote:

> "jim holland" <gordi(a)talktalk.net> wrote in message
> news:345cb808edc24accbb58f4f211f0ecf6(a)newspe.com...
>> Hi All
>> I have ford Galaxy 2.3 1999 its LPG/Petrol the system is a single point
>> emmegas, when pulling away from standing start on LPG if the engine
>> labours
>> or I try and accelarate to fast it backfires but if i'm a bit more
>> gentler on acceleration its ok when it gets going its fine taken it on
>> motorway it drives great has anyone any idea what causes the backfire
>> and how to stop it?
>>
>> cheers
>>
>> url:http://myreader.co.uk/gp/1272-1.aspx
>
> Could be a weekness in the ignition system, changing plugs and leads may
> cure the problem. Emmegas systems aren't the best unfortunately, my
> previous car had the same system, & even with new plugs and leads, it
> was still prone to the odd backfire.

be careful, I blew a alfa 155 inlet manifold to pieces with an almightly
backfire one day. a lot of cars now have plastic manifolds as all they
would normally hold is air. with LPG you suddenly have an explosive
mixture. Get a blowback valve fitted to protect your wallet.

From: andrew on 18 May 2008 17:15
jim holland wrote:

> when pulling away from standing start on LPG if the engine labours
> or I try and accelarate to fast it backfires but if i'm a bit more gentler
> on acceleration its ok when it gets going its fine taken it on motorway it
> drives great has anyone any idea what causes the backfire and how to stop
> it?
>
I think it's to do with valve overlap and flame speed, at full throttle and
low revs (ignition retarded) and if the mixture is weak the exhaust valve
can open while the gases are still above the autoignition temperature of
the mixture. as the gases don't have the inertia they would at high and in
a multi cylinder engine there will be another cylinder during its valve
overlap phase so there is the chance of a flame path from the exhaust
manifold through the fresh mixture in the cylinder and out through the
inlet valve.

At higher revs the natural momentum of the gases in the exhaust scavenges
the system.

I often have the opposite problem where the mixture doesn't fire and carries
through to the exhaust and is subsequently detonated there by the next hot
exhaust stroke.

AJH
From: Mick Albin on 10 Jun 2008 16:10
Hi,

I have a Ford Scopio with the 2.3 engine and I have had converted years ago,
but it does have an habbit of back firing in the inlet manifold. It only
does it every
couple of months, more so on cold damp winter mornings.

The back fire manifests its self in blowing out a vent plung at the very
back of
the inlet manifold. This was a shame as the first time it happened I lost
the plug
somewhere down the hard should on the M6 one evening and after being towned
home
and the garage had to machine up a repace plug. Sine then this has been
firmly
attach to the breather pipe by a juble clip and I have not have any problems
with
just pushing it back when it pops out.

The car is fitted with a flap value on the air input but the backfire seems
to be a lot
further in the system and it does not operate.

One theory about why it happens is, it seems to happen when the weather is
fairly
damp and this dampness could be generateing a static on the plasic inlet
manifould.

At one time Ford Explorers that had been convered to LPG where known widely
as "Exploders" !!!!!!!!!

Mick



"jim holland" <gordi(a)talktalk.net> wrote in message
news:345cb808edc24accbb58f4f211f0ecf6(a)newspe.com...
> Hi All
> I have ford Galaxy 2.3 1999 its LPG/Petrol the system is a single point
> emmegas, when pulling away from standing start on LPG if the engine
> labours
> or I try and accelarate to fast it backfires but if i'm a bit more gentler
> on acceleration its ok when it gets going its fine taken it on motorway it
> drives great has anyone any idea what causes the backfire and how to stop
> it?
>
> cheers
>
> url:http://myreader.co.uk/gp/1272-1.aspx

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