LJ70 2LT losing fuel prime

[peakbagger]

My 94 LJ70 has been in the yard for 6 months while I work on it. One thing that is pretty consistent is if it sits for more than week or two it will not start due to lack of fuel. If I open the hood and push the primer bulb multiple times eventually I feel it firm up and eventually can hear fuel returning to the tank. Any suggestions on what to check first?

Once its started it will start fine foe a day or two.

 

[coldtaco]

Time to look for a leak.

 

[peakbagger]

No obvious external fuel leaks

 

[vipergrhd]

Look for any rubber hoses going into your lift pump or after the lift pump, small leaks may not be visible. I'm not familiar with this engine set up but do you have a mechanical lift pump? It is possible that it could leak internally.

 

[Waikato Willy]

change your primer, Im a cheap a#@ and just stole the primer off my paddock basher nissan patrol, and it holds hard prime even after sitting for 2 weeks, yet my leaky toyota one works a treat on my paddock basher, go figure, motors must be really susceptible to air locks in the diesel line

lines are easy to pressure test as well, on my KZJ78 all the fuel lines are behind the rear right hand wheel under a plastic cover, I pulled the main feed off and blocked it up , then I poked an air gun down there, used a regulator to put 8 psi down the line with a bit of diesel and looked for leaks

 

[peakbagger]

Still just getting to know the systems. I already picked up a spare primer/filter housing but did not install it as the old one seemed to work. Someone had mentioned using the Bosch style primer and said it screwed right in but I sure did not see that option on my housing. Once I swap the old one out I will rip into it and see if I can adapt one into it.

 

[roscoFJ73]

Fuel system leaks are from vacuum. You don t see fuel leaking out until it gets bad. If you have a rotary injection pump, you can not use the Bosch hand pump as the filters that come with them have the hand primer on the filter head.
These sometimes leak air around the filter

 

[John in Utah]

Check the water sensor drain screw at the bottom of the filter. There’s a little rubber o ring in there that can get brittle and let just enough air in it without having a noticeable leak. I had to close mine up by melting the plastic with a lighter to get through a long road trip.

 

[peakbagger]

Check the water sensor drain screw at the bottom of the filter. There’s a little rubber o ring in there that can get brittle and let just enough air in it without having a noticeable leak. I had to close mine up by melting the plastic with a lighter to get through a long road trip.
View attachment 2422899

Interesting, that looks a lot like the radiator plug which had a leaky ORing that started leaking after I drained the radiator. Definitely one to check.