LPG mechanics

[davek]

G'day all, amongst the wonderful bunch of members here would any one be an LPG mechanic or have fair knowledge of the systems, I have a problem I'm trying to sort out, any assistance will be gratefully accepted. cheers davo

[andyk]

Whats the prob ?

[davek]

I have a problem where when I change from petrol to gas It won't change, not all the time but most times. I thought it was the switch so I changed it and it was ok for about 3 changes. Could it be or is there something else like a solenoid or relay that could be the problem, cheers davo

[andyk]

Sounds like the solinoid ckeck the wire connections on the solinoid it self and the one at the tank . Does it operate when car not running but with ignition on ? U can test it that way turn ign on then switch from p to g and hear that the solionid is working ok .hope that helps.

[davek]

thanks, I'll give it a try and let you know, cheers davo

[bowl]

My lpg switch does ,pickz n chooses when it will go on gas.always switchez pn petrol

[rixter]

Yep , as above. Although not very often a solenoid dies , but relays are known for sticking and burning out. Check the relay also .

It's going to be one or the other I recon' .

The wiring is a lot like that for High wattage car spotlights. Switch (low amp 12v switch) in your car / goes to the relay switch which is a high voltage/amp switch (so you don't burn out the contacts or the wiring to the small switch in the car) the relay is powered by the battery / the relay powers on/off to the spotlights.
With LPG the above is the same , except you have a solenoid at the end of the line instead of spotlights; and the solenoid powers the valve to change from gas to petrol or petrol to gas. (all in a quick nutshell, there's a bit more to how each part controls each other and so forth, but that's the basic principle).

(off topic a bit , but) A good tip for spotlights, instead of powering the relay from the battery, wire the relay to the back (positive +) of one of your normal driving lights. This way your spotlights won't work unless your headlights are on , and if you forget to turn off your spotlights they will go off automatically anyway when your turn off your headlights.

Spotlights, Solenoids, and some other electrical devices draw a lot of current/amps. This is why a high current/amp electronic switch (a relay switch) is needed to turn on or off these devices. Otherwise any low current small wires or switches (as in the wires and on/off switch in your car) would burn out from the high current, or back emf generated from items such as coils (solenoids).

I'm no LPG mechanic, but this is the electrical side of things, which I'm familiar with how it works.

Cheers , Rick.

[davek]

Thanks Rick, all taken on board. I won't be doing anything until the morning, had a big day at work and walked about 20 ks further than I wanted too :sleepy1: cheers davo