> Since the engine is an injected DJ model, Jason had to
> disable the petrol injectors when switched over to  gas. This
> is so because the engine must be started on petrol. (I have
> not discovered why this is necessary because on a cold engine
> the running is much smoother on gas).

I'd guess it's necessary because, on a cold day, there may not be enough
heat available to properly vaporize the propane until the engine is warmed
up.

---- reply --------

We can have very cold days where I live and people here with propane
vehicles (there are a lot of them) do not have vaporization problems.  The
engine coolant heats up in time to warm up the LPG converter.  In fact, I
always put in a valve in to reduce coolant flow through the converter as it
gets too hot.  Actually, I can't see the propane converter contributing
anything significant to the cooling loop because the LPG flow is pretty low.

The easiest way to turn off the petrol injection is to cut the ground to the
injectors (have it switchable).  I do this at the ECU connector.  This keeps
the ignition functional.  You can shut off the fuel pump if you want.

You should not need to start the engine on gasoline and then switch to
propane.  If you need to do this, something's wrong with your installation.
It could be that the vapor hose is very long and there is no priming
circuit.  Or a leak.  I've actually never bothered to hook up a primer as it
has not been needed.  All my conversions started fine on propane.
There are a lot of conversions which are propane only, not dual fuel, so it
is not possible to start on gasoline.

At the moment, propane is $0.44 per liter in Calgary, gasoline is $0.80 per
liter.  Last year I was paying $0.16 per liter for propane at one point.
The vast majority of the time, the spread in price between propane and
gasoline favors running on propane.  Sometimes by a considerable margin.

Vanagon propane conversion
http://www.telusplanet.net/public/gary2a/rack/propane/propane.htm
BMW propane conversion
http://www.telusplanet.net/public/gary2a/rack/bmw/bmw.htm

Gary  Lee
http://www.telusplanet.net/public/gary2a/rack/vanagonrack.htm