Hzj75 4.2 fuel issue? (1 Viewer)

[Zijad]

Hi guys,

I have bought a hzj75 4.2 from 1995 a few years ago. At that time the engine was running as a swiss watch
Since the toyo was stored and unused for approx 2 years. I renewed the clutch last year and since then (could be coincidence) the engine stops running after a minute or 2-3. I then pumped the manual pump and the engine runs again for 2-3 minutes.
I then connected the fuel supply to an external fuel source and so surpassing the manual fuel pump, and the engine then keeps running as it should.
Could the cause only be the malfunctioning manual pump or are there other possible causes?
Thanks for your help!

 

[DamoPeru]

Did you change the diesel? It goes bad and clogs stuff up.

 

[Eco 45]

Could be the pump, but if the truck has been sitting like damienperu stated change the fuel. In addition replace the fuel filters and then see what happen. Diesel fuel can go bad and things can grow in it. Once those two items are checked then move on to testing the pump.

 

[roscoFJ73]

Could the cause only be the malfunctioning manual pump or are there other possible causes?

Its possible. It could also be the fuel filter rubber seal has shrunk and is letting air in. Remove , wipe the seal with diesel or oil and replace.
It could also be cracked fuel line ends or fittings that need tightening. Its something simple as it runs when you add a temporary fuel supply.

You can use diesel that's 10 years old if its been kept clean and dry. If it was bad diesel it would be coughing and spluttering.

 

[Zijad]

Hi All, thanks for your advice. Filter was replaced already but that did’t do the trick. I will recheck the fittings and lines. I added 25 liters of new diesel to the low level of fuel it was. Perhaps wrong assumption but i would think that it would be mixed enough. But...assumptions...
If the fitting and lines are ok i will place a new manual pump.
I will keep you posted.
Thanks so far!!

 

[roscoFJ73]

The best way is to temporarily fit a clear line before and after the hand primer. This will show if the air bubbles are getting through the filter head.
Fuel will be ok.

 

[Zijad]

Hi Rosco, thanks for your advice. I will do that!

 

[Zijad]

Hi Guys, one addition to this which I realized it could be relevant: when I used the separate fuel source the engine smoke was nearly none. When it was connected to the original fuel tank, it was smoking a lot. So like you've said, the diesel could be in bad condition also, that doesn't help...

 

[roscoFJ73]

Usually you can tell by looking at it. If diesel fuel has been stored properly it loses some of its power over a long period but its still ok to use. Its only if its get algae in it that it becomes a problem.
Algae forms at the top of the tank where there maybe condensation
You might want to throw a bottle of diesel fuel conditioner into the tank. Then do a few filter changes.
Do you have a pre filter? They are a good spot to check for any impurities in fuel as you can inspect the filter without cutting it up.

 

[Zijad]

Hi Rosco, thanks for your quick reply. No pre filter present. I will run the test showed above with the transparant hoses to see if air is visible in the lines. When the primer is ruled out and hoses are ok, I will go for the fuel conditioner. I was not aware of that being possible.
Thanks again

 

[roscoFJ73]

Those fuel conditioners kill anything living in there and the remnants of the dead beasties clog up your filter, hence the need for filter changers.

The smoking could also be from a lack of fuel due to air getting in. What colour smoke was it? I think if you had air in the injector lines it would interfere with the cracking pressure of the injectors because air is compressible. So it would have an effect of possibly causing the injector to open late.