From: Nomen Nescio on
I bought a car what is dual fuel. It would not start on
LPG unless the motor was warm. Otherwise, you had to start
on petrol, and rev over 1500 RPM before switchover.
I changed the spark plugs, leads and air filter -
that helped none.
Next I put in a larger battery (from a V8, mine is a V6)
and changed the oil to 5W40. The owner handbook says
use 20W50 or 10W40, if you live in cold climate.
Now she will start cold on LPG. I hypothesise that now
it cranks over slightly faster, permitting starting on
LPG.

From: Hachiroku ハチロク on
On Fri, 16 Jul 2010 09:48:25 +0200, Nomen Nescio wrote:

> I bought a car what is dual fuel. It would not start on LPG unless the
> motor was warm. Otherwise, you had to start on petrol, and rev over 1500
> RPM before switchover. I changed the spark plugs, leads and air filter -
> that helped none.
> Next I put in a larger battery (from a V8, mine is a V6) and changed the
> oil to 5W40. The owner handbook says use 20W50 or 10W40, if you live in
> cold climate. Now she will start cold on LPG. I hypothesise that now it
> cranks over slightly faster, permitting starting on LPG.

LPG has always been hard to start on when the engine is cold. Here in New
England, everyone I knew of who had dual fuel cars would start in gas and
run the car (or, more accurately, truck) on gas until the engine warmed up.



From: Paul on
Nomen Nescio wrote:
> I bought a car what is dual fuel. It would not start on
> LPG unless the motor was warm. Otherwise, you had to start
> on petrol, and rev over 1500 RPM before switchover.
> I changed the spark plugs, leads and air filter -
> that helped none.
> Next I put in a larger battery (from a V8, mine is a V6)
> and changed the oil to 5W40. The owner handbook says
> use 20W50 or 10W40, if you live in cold climate.
> Now she will start cold on LPG. I hypothesise that now
> it cranks over slightly faster, permitting starting on
> LPG.

http://www.propanecarbs.com/propane.html
Look for ignition temperature.