UZJ100 GCC specs with factory auxiliary tank, won’t start on main tank unless I give it enough power. (1 Viewer)

[BajaSupreme]

So this issue popped up when water entered the driver side dash and caused loads of electrical issues, most of them have been solved but the thing that’s driving me nuts is the car won’t start on main tank “sometimes”.

Meaning, if I crank the engine, it starts, and the tachometer goes above 1K rpm. But then doesnt idle, and if I give it gas the engine shuts down even faster.

So it’s apparent the engine isn’t getting fuel, If I switch to sub tank and give it gas for a couple of minutes and then switch to main tank, it runs perfectly.

Now on the second try, if I remove key and try to start again on the main tank, it doesn’t like to idle, but if I switch to SUB tank again and give it just a little gas (like staying at 1K rpm) then it idles on the main tank and everything works even if I give it gas.


I tried to do the third time, removed the key and started on main tank, didn’t work. But this time I just pressed the switch to change to sub and back to main again, without giving gas and it runs as expected.


I tried to look for a Fuel Pump Control module but my 1FZFE doesn’t have it, instead there’s a fuel relay on the back. And I hear the clunk noise when switching from one tank to another so it’s not a switching issue.

It’s just my main fuel pump isn’t getting enough current when starting. And help will be highly appreciated.

 

[Bardiya]

Is your "SUB" light flashing?

 

[BajaSupreme]

Is your "SUB" light flashing?

Do you mean when the main tank runs out of gas? No it doesn’t since it’s always showing empty even though there’s fuel.

I thought this was due to my fuel gauge not working ever since it got short circuited.

But the SUB light does come on when I press the switch, and the low fuel light is still active on the sub tank as well.