LPG Conversion question

TigerMog · Posted: Sat Aug 30, 2008 6:27 pm Post subject: LPG Conversion question

OK, today I started the conversion to run on gas. Dual fuel set-up. I have run all of the hardlines and fittings. I am now down to the wiring bit. I have a dash mounted switch with three positions. LPG only, no fuel at all, and Petrol. There are solenoids for both the LPG hard line and the petrol fuel line. My question is this. I run an electric fuel pump. Is there any reason I cant skip mounting the petrol solenoid and just run the hot wire from the dash switch to my fuel pump? When switched to LPG it should have no power to the electric pump and no petrol to the carb. Is this sound? Or do I need to stare at it and have a few more beers?

RobotMan · Posted: Sat Aug 30, 2008 8:48 pm Post subject:

I would fit the solenoid and run the hot wire to both then it's a double shut and the solenoid will stop it drawing petrol and the possibility of over fuelling.

shaggy · Posted: Sat Aug 30, 2008 10:54 pm Post subject:

I have no opinion on your actual question, but if you get a leccy pump, bear in mind the mog fuel system only runs at about 2psi. Those with electric pumps usually run a regulator with or without a return line. Otherwise you flood the hell out the carb.

jim

simonallen · Posted: Sun Aug 31, 2008 12:04 pm Post subject:

if you just cut off supply to the fuel pump, you will have a few seconds where the carb is still using petrol AND gas no? may cause havoc with the running of it.

TigerMog · Posted: Mon Sep 01, 2008 11:23 am Post subject:

hmmmmm isn't there going to be a period of time when there is petrol and LPG no matter what? Based one the amount of fuel in the carb bowl, the fuel line etc, no matter what there will be fuel forward of either the fuel pump or the cut off solenoid. I think I will have that few seconds of both fuels no matter what I do wouldnt I? I know the fuel pump I have does not have a backflow valve, so as soon as it is off all the fuel in the line drains back to the lowest point anyways. I am not sure if I would have that with the solenoid or not, but regardless it will take a few seconds to work through all of the petrol already in the carb bowl.

TigerMog · Posted: Fri Sep 12, 2008 7:43 am Post subject:

OK, as I completed the kit my question was answered for me. The dashboard switch actually has three settings. I thought there were only two, LPG or Petrol. the key is the third setting is for no fuel at all. So I start the engine on petrol, let it warm up, switch to the no fuel at all setting and wait for it to burn through the fuel in the carb bowl and lines, as soon as it starts to sputter from lack of fuel I switch to LPG and avoid the dual fuel scenario. So far so good!