(Another) LPG Issue

[CRCinAU]

Hi all,

I'm trying to find the source of this problem thats just cropped up in my trusty VR... (440,000km!).

When I start the engine on petrol and drive, everything is fine.

As soon as I flick the switch over to LPG, the motor dies. It doesn't start or run at all on LPG. The LPG system is a factory fitted impco.

So. I've checked the fuse in the red lead (that I think goes to the gas solonoid) in the boot above the tank, that tests ok. There is however no voltage on this wire - even with the key to ignition and the LPG button depressed. The control module behind the glovebox has 2 LEDs (green and red) and neither of these are lighting up. I'm also not getting any voltage on the gas solonoid under the bonnet (where the line feeds into the evaporator).

I've checked all the fuses under the drivers side dash, all are supplying power ok - no blown fuses. So now I'm trying to find out where else to check. As with all cars, the wires from the controller seem to disappear into a wiring loom that goes god knows where....

To me, it seems like the whole thing just isn't getting power.... The question is, where the hell does that power come from?

Any suggestions / other things to check from the wise folks here?

 

[Wozza]

faulty switch ?

 

[CRCinAU]

I just thought about trying the solonoids directly.... I took the single wire off the solonoid and connected it to 12v and sure enough, the solonoid triggered, so its certainly not that....

I've pulled out the LPG / Petrol switch (has the number 92O49938 on it) and trying to figure out how it works - yet I can only measure (using a multimeter) one set of contacts that seem to connect. I've tried many other combinations and can't seem to get anything out of it...

Is there a wiring diagram / pinout of what this switch is supposed to do?

 

[aussie4life]

if its factory fitted, check the fuse box under the bonnet. see if there is a fuse or relay for it under there.

 

[CRCinAU]

faulty switch ?

I'm wondering that... If only I can find out how the switch is supposed to work

if its factory fitted, check the fuse box under the bonnet. see if there is a fuse or relay for it under there.

Checked all the fuses etc in the box next to the battery, all measures ok there... Would there possibly be any hiding elsewhere?

 

[CRCinAU]

Ok - so I was suspect that it was the switch, but I couldn't find any kind of information on it....

So, upon further inspection, I noticed that the switch was the pull-apart type. So I did what everyone in that situation would do - I pulled it apart...

Then I noticed there was a lot of hard crud around the copper contacts on the inside, so I scratched that off with the tip of the multimeter probes, then reassembled the switch. Took it back to the car, plugged it in - and as soon as the contact was made I hear the LPG solonoids make that magical sound *THUNK*.

Now the LPG system has power again, the controller has its red/green lights flashing away - and better still, it starts and runs on LPG again.

I never would have thought it would have been something *that* simple

Thanks guys.