FJ62 Fuel problems

[Infidelious]

Hi all, we have an FJ62 dual fuel, runs perfectly on gas without fail and smoothly on fuel around town. Problem is once fully loaded after about an hour, there is a severe lack of fuel causing it to cough and splutter, eventually undriveable and you cannot restart on fuel. Still runs perfectly on gas when changed back.

We have had the carby adjusted to factory specs, the ignition points replaced, and the LPG mixture knob adjusted correctly. We also had all fuel lines checked, no leaks.

Thinking it has to be between the carby and the fuel tank. possibly the fuel pump. Being that it runs perfectly on gas, and petrol for the first hour, we think we can safely eliminate electrical, plugs, points, carby or lpg system, that leaves us with the fuel system between the carby and the tank.

What is confusing us is why it will run perfectly on either fuel till it is under load for at least an hour and a half and it only does it on petrol.

Any ideas?

Cheers Matt

 

[3_puppies]

the problem happens when running it on gasoline? did you try running with the gas cap off? could be a tank venting issue not letting air into the tank as the gasoline goes down.

 

[LAMBCRUSHER]

down under, gas is LPG, petrol is liquid gasoline. I am gathering that you are having issues running on both? what does the temp dial indicate when this issue arises? wondering if you have a temp actuated vacuum leak. there are temp switches that allow vacuum passeges to open upon reaching full operating temp. if the downstream vacuum passages from this BVSV (bimetallic vacuum switching valve) are open to atmosphere, you will have trouble regardless of type of fuel used after this...Might also do a valve adjustment for good measure- I think they fix all problems, myself...if the issue happens on both types of fuel, then it will be due to something common to using either. if it is only when using one type of fuel or the other, then that gives you some insight into where to look...I'd check all vacuum tubes and doohickies, and adjust the valves...


edit, I misunderstood- it seems to be only on petrol? vapor lock. check for clear vent tubes and no cracks in vapor separator and no clogged charcoal canister and functional VCV on charcoal canister....as 3pups said, try running w/o cap on. if the system can't breath, it will lock up...

 

[Infidelious]

Thanks for the advice guys, we had a local mechanical guru come round. He installed another fuel filter between the pump and the carby, start her up and the fuel is just trickling into this filter. New pump on the way, once installed its load her up and set out on a 200k drive to see if it's fixed our problem.
Thank again to the replies and we will post results when we find out.