QUESTIONS ABOUT LPG SETUP

[Shorty40]

1992 EFI GQ on straight gas. Recently installed in the last couple of months.

Questions:

1. Whilst driving, on very light throttle input (like in a carpark or a 40kph zone) I can here a sound coming from about where the converter is. It sounds like an old dot-matrix printer Is this normal ?

2. Start up takes about 5 seconds of cranking (doesn't sound long, but it is when you are doing it). Is this normal ?

3. Should I be able to smell LPG under the bonnet ?

[Screwy]

The amount of time it takes to crank is normal.....
cause its straight gas and doesnt have a primer it will take that long.

U should not be able to smell any LPG at all under bonnet as such.....

If u smell around the carbi or the converter... u may smell a light vapour of it coming from either the breather on the side of the converter ( if it has one ), or the air filter.......

the ticking im not sure about, mine doesnt do it and the other 2 LPG rings i have had / have dont do it either

cheers

[80UTE]

Being on an EFI engine there is a high chance it has a feed back sytem (closed loop) to control the mixture via the oxygen sensor and a LPG mixure controller computor. This works with a small soleniod valve that pulses and varies the vacum acting on the LPG convertor diaphragm to alter the mixture. At higher engine speed and power level the computor goes in to open loop and this pulsing soleniod will stop and the noise will most likely stop.

Wally

[hotrod4x4]

LPG on my carbied patrol / mav used to always get the smell under the bonnet.....or around the area after u stop sometimes

it was tuned a little richer than normal to get more outa it tho

but apart from that
never any leaks.......and was often checked
and every rego......never a problem with leaks or valves etc


my cranking time varied
maybe 5 secs? first up in the mornings
but after that , always pretty normal

[J Top]

Have you tried varying the throttle position, the reg requires vaccum to activate, closed throttle, but the butterfly may need to be opened slightly to allow the gas into the engine.
J Top

[modman]

you can fit a primer line straight into the intake after the throttle body.
hit the primer button under the dashfor 2 secs then hit the key
wire the solinoid up to ignition so that it won't fire while the engine is running.
i have seen this done on low compression turbo motors to cut down cranking time
don't mention legalities, i don't want to know
when the motor is turned off overnight the gas dissipates all the way back to the lock-off.
therefore when you start the motor the gas has to enter the convertor change state and pressure then travel through the intake, throttlebody, then into the cylinder.
like trying to start a car with empty carby/fuel bowl i guess
david

[CRUSHU]

primers are quite legal, and usually they are hooked up to the ignition, so when you turn the ignition on, it primes. it involves another solenoid on the convertor, to a hose to the manifold.

[jessie928]

the reason you have to crank a bit longer in your injected car is because its straight gas. this is normal, as the mixer is relativly furhur away from the combustion chambers than on a carbied vehicle.

being straight gas you dont have a squirt of fuel to start the engine up either.

DONT add a primer, this will just flood the intake with an unesseary amount of fuel.
JEs