Virtual Mechanic » LPG Vehicles

LP GAS The tank

virtualmechanic — Sat, 17 Oct 2009 22:32:32 +0000

PURPOSE
The tank is designed to store liquid gas, and depending on the country, may come in many different shapes and sizes, providing different capacities. An LP gas tank is checked before it is sold and is best checked every ten years for leaks or wear. Gas tanks are designed to hold eighty percent of their capacity to allow for expansion.

THINGS TO LOOK FOR
An LP gas tank may be checked with warm, soapy water for leaks as well as dents. It is important that the tank is positioned correctly to allow the gauge to maintain an accurate measure of the liquid gas inside the tank. Tanks must be secure and the gas tap must be easy to turn on and off.

IS IT EXPENSIVE TO REPAIR?
If a gas tank requires replacement it’s best to purchase a new tank or a reconditioned tank as this will show a certified ticket to ensure it is a safe tank to use.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If the gas tank appears to be leaking, turn the gas tap off and take it to a qualified gas installer for a check up.

LP GAS PETROL SOLENOID

virtualmechanic — Sat, 17 Oct 2009 22:31:14 +0000

PURPOSE
The petrol solenoid is designed to allow petrol through it when energised, may be applied when starting up the vehicle on gas. Some vehicles fitted with electronic fuel injection may automatically start up on petrol, then when the rpm reaches 2000 the engine will switch over to gas. Therefore it is important to keep at least a 1/4 tank of petrol for this reason.

THINGS TO LOOK FOR
Petrol solenoids are only as good as their connections. Petrol solenoids are usually mounted to a heater hose or are just freely connected to the fuel line making it very important for the earth and the positive to have enough slack to move with the solenoids. So when you rev it, the engine moves and so will the solenoid. A common problem is the connections become loose or the terminals are just crimped and not soldered then it is just time before the petrol solenoid will not operate.

IS IT EXPENSIVE TO REPAIR?
If you know how to solder terminals, this is the cheapest way. Otherwise visit your local mechanic or auto electrician. The cost is around $30.00 to solder a few joints.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If it seems to be impossible to get the power to energise the petrol solenoid and you just want to drive to your local repairer then carefully connect a fuse wire from the battery to the petrol solenoid to drive it on gas.

LP GAS Mixer

virtualmechanic — Sat, 17 Oct 2009 22:29:36 +0000

PURPOSE
The mixer is designed to mix the low pressure gas with the correct measure of air creating a specific air fuel ratio, providing a combustible mixture ready for the combustion chamber.

THINGS TO LOOK FOR
The mixer rarely goes wrong so long as it is connected correctly. Over a period of time the air gallery lodged under the tubing may work loose and the tubes need to be resecured. If the tubes are cracked on the ends it will be necessary to replace these rubber tubes.

IS IT EXPENSIVE TO REPAIR?
If the mixer is 5at fault it may cost around $60.00 fitted.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If the large rubber tubes are torn or cracked it may be possible to gaffer tape them so you can drive to your local qualified gas installer or spare parts outlet.

LP GAS Gas solenoid

virtualmechanic — Sat, 17 Oct 2009 22:28:12 +0000

PURPOSE
The gas solenoid is designed to allow liquid gas to pass through when it is energised. The gas solenoid is energised by 12 volts supplied from the safety switch. The gas solenoid switch is most reliable when the earth connection is secure and the positive connection to it is soldered. The gas solenoid may also carry a filter. This filter ishould be checked every 10,000Kms to prevent it from clogging up.

THINGS TO LOOK FOR
A very common problem is the gas solenoid bracket, which is mounted to the body, becomes slightly loose and the mounting screws holding the earth lead may also be loose, making it a bad earth connection. Another common problem is the positive terminal connection is not soldered to the positive lead making it a bad connection. It is only time before these problems prevent the liquid gas from flowing through. When travelling at a moderate to high speed you notice that the vehicle slows down, it might be a sign that you are low on gas or it may be a gas filter clogging up.

IS IT EXPENSIVE TO REPAIR?
Servicing the gas solenoid filter or resecuring the connections is not expensive. If you get a qualified gas installer to do this, make sure they do it properly, so you are not going back 2 or 3 times with the same problem. It is very important to have all connections soldered.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If the power has trouble coming through from the safety switch don’t bypass it as it is the safety switch, which in case of an accident, will turn off the gas if the engine stops.

LP GAS Convertor

virtualmechanic — Sat, 17 Oct 2009 22:26:21 +0000

PURPOSE
The gas converter is designed to receive high pressure liquid petroleum gas and convert it to a low pressure gas. This is achieved by water passing through this component to prevent it from icing up. The gas converter consists of two chambers, a high pressure chamber and a low pressure chamber attached to a diaphragm which is connected to a needle valve to allow the low pressure gas to the mixer thus mixing the air at the correct ratio ready for the combustion chamber.

THINGS TO LOOK FOR
The converter requires the cooling system not to leak because the converter uses the flow of water to prevent the converter from icing up. This is the most common and dangerous scenario because the icy converter body may distort, allowing high pressure gas through the unit. If you find the converter icy turn the gas tap off at the tank and get it attended to A.S.A.P. Another common problem is the cooling system connections begin to leak. Get it attended to A.S.A.P. as this will affect the function of the converter. Another problem is the converter malfunctioning, if it does this it will stop.

IS IT EXPENSIVE TO REPAIR?
Repairing or replacing a converter may cost around $180.00 depending on the brands. Because there are so many parts in a converter you can go either way, repair or replace it. But it has to be done by a qualified gas installer.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If it is found that the converter is icy do not pour hot water over it as this may crack the converter body. Allow the temperature to go down by itself with the gas tap turned off at the tank. This may take about 30 minutes to an hour.

Gas Adjustments

virtualmechanic — Sat, 17 Oct 2009 22:24:42 +0000

PURPOSE
The gas adjustments are calibrated best by the use of a Dynometer as this will provide the most accurate measure of torque thus maximising the fuel economy. There are basically three adjustments to be made on any gas system. They are idle, cruising and full throttle. The idle should be the only one requiring adjustment and the full throttle and cruising adjustment are best performed on a Dyno by a qualified gas fitter, preferably every 10,000Kms.

THINGS TO LOOK FOR
Heavy fuel consumption is one indication that the gas system requires adjustment. Most gas vehicles can be running too rich. Another indication is a lack of power. These two problems are difficult to rectify but if your engine idles rough check that all the rubber ducting is in order and well secured. A sign for running rich or running rough is a dirty air cleaner. Be sure that it is not blocked or built up with dirt. After checking all these components, the last thing to do is adjusting the idle, but remember where you started as this may make no difference so if it doesn’t return the adjustment, screw to the original position

IS IT EXPENSIVE TO REPAIR?
A good Dyno tune may cost around $95.00 and a good Dyno tune should improve your vehicle’s performance and economy.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
There is only one temporary adjustment and that is the idle. Other than that, the adjustments will affect the vehicle’s performance and the emissions entering the atmosphere.

LP GAS

virtualmechanic — Sat, 17 Oct 2009 22:21:04 +0000

PURPOSE
The basic function of a gas system is the liquid gas is stored in a tank under pressure. When the ignition is turned on and the toggle switch is switched to gas, a safety switch is energised by a pulse from the ignition system switching the gas solenoid on allowing gas to pass through the solenoid to the converter. The converter receives high pressure liquid and converts it to a low pressure gas, delivering it to a mixer. The mixer then mixes the air with the gas at the correct ratio as it enters through the carburettor and manifold.

THINGS TO LOOK FOR
The best gas system is the most reliable gas system. All gas systems require the cooling system to be in good condition as heater hoses are attached to the converter to prevent the converter from icing up. If it does ice up it could be a potential danger zone . An icy converter is a dangerous converter because the internal mechanisms may allow high pressure through the system if the converter becomes faulty.

IS IT EXPENSIVE TO REPAIR?
The converter is expensive. Unless it has a faulty diaphragm, it might be cheaper and faster to have a changeover converter than having it overhauled and repairing the items that are faulty.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
No temporary repair on gas. The only temporary repair is to turn it off if it’s faulty and run it on petrol until you get the gas fixed.

LPG Vehicles

virtualmechanic — Fri, 14 Aug 2009 04:40:07 +0000

Recently have you noticed that when you shop around at different suppliers or stations that some times you seem to get more per km. Well I have decided to conduct a simple test over the next month. My plan is to choose the major fuel outlets to see if I can get more per km or if they are all the same. Now don’t let me do all the hard work, if you wish to participate join me and offer your experience.