Mitsubishi L200 2.8 engine cutting out

[Mark2468]

I wonder if anyone out there can shed light on this problem?

My L200 warrior 2.8 keeps cutting out after a short period of time, acts as if starved of fuel.
Tank filter clean
Solenoids working
New fuel filter and fuel line
No obvious leeks or drips.

It can run for regular times before loosing power/revs and stoping, sometimes 7 mins at a time, and sometimes 20 mins.
The engine will start again after some turning (or hand priming to save battery), but will then run fine, until it looses power and stops again.

I have a transparent pipe on the return outlet from the mechanical pump (no electric pump) and fuel stops flowing back as it begins to loose power and stop, while the solenoid stays open.

I’m thinking the fuel pump may be faulty and affected / worsens by temperature?

Any one have any knowledge or experience here ?

[Penelope Stopit]

What's the shortest length of time it will run for

If the answer is 2 Minutes

Will the engine keep running if squeezing the primer bulb several times every other minute or so

At least the above may prove a point

[GreenV8S]

The symptoms suggest the pump stops working after a while. Perhaps you have an air leak at the pump or on the intake side of it, causing the pump to un-prime.

[Mark2468]

The shortest time it runs for is 7 min, I prime the filter to ease re-star and it will run for another 7 min,
(sometimes the equall run times are longer)

It appears to run in exces of the reservoired fuel in the filter on different days, but usually for the same durations .

[sunbeam alpine]

Have you tried running it with the fuel filler cap loose/removed?

A few years back I had a similar problem with a LR Discovery. My 84-year-old neighbour diagnosed the problem, much to my embarassment!

[Mark2468]

A leak at the pump etc was suspected but nothing obvious can be observed. But the regular “run” times before cutting out each time seems to suggest something more may be going on.

[Mark2468]

Yes I have ran it with fuel filler cap off, but...... thinking about it just now I remember there is a secondary “trap door” down in the tank, if the pump struggles cause of poor breather on the tank that would explain the equal run times before cutting out.
I’m not taking for granted this is the problem but it’s something I will have to rule out by poking something down there to open it !

[stevieturbo]

Try sucking fuel through the filter to see if there is a restriction.

[Mark2468]

Done that, no restriction, but like I mentioned earlier I will have to open the little trap door with a bit ow wire in the fuel filler to allow air in to the tank, I think that after 10 min or so the pressure in tank might be to negative for the pump to pull it through, so it might be a simple tank vent/breather problem, but will check that out tomoz

[GreenV8S]

Mark2468 said:

I will have to open the little trap door with a bit ow wire in the fuel filler to allow air in to the tank,

If you're thinking of the anti-surge valve at the filler neck, it seems pretty unlikely that would hold a vacuum. I'd be looking for a cracked pipe, porous hose or poor connection on the suction side of the pump.

[Mark2468]

Well... I can rule out the fuel tank breathers cause I can blow in through the one tube and hear it coming out of the other.
I’ve checked the siv/ filter in the tank and it’s clear blew down the inlet and outlet tubes in tank and they are clear.
I’ve put new tubes from tank to filter .
I’ve put on new filter.
And the problem persists!
It runs for aprox a set amount say10 to 30 mins then stops from apparent fuel starvation.
UNLESS!!!!! I run it from a gallon can with two hoses coming out to the fuel filter housing and the return outlet on pump,
Runs for hours then !

So.... the mystery continues!

[GreenV8S]

Mark2468 said:

So.... the mystery continues!

The symptoms all support the diagnosis of an air leak on the suction side of the pump - you just haven't fixed it yet.

[Mark2468]

I’ve made a temporary repair !
I thought I’d run my makeshift repair by people.
Firstly the fault, being (presumably) the diesel fuel pump.
The truck would run for a certain amount of mins, and then stop from fuel starvation.
Sometimes it would run for ten min, loose power/stop then with a bit of hand priming to save bat it would run for another ten min, and so on and so on , regardless of temperature.
Solenoids good
Fuel line good
Fuel tank and siv good
New filter
Everything as it should be but still stopped.........UNLESS! I put a gallon fuel can on engine and run two short pipes from filter housing and fuel pump in to it, then it would run all day.
SO..... I bought a small 12v generic in line fuel pump off e bay and put it just before the filter, shoved the live wire in to side lights in fuse box , and the Neg to battery terminal,
Now as long as I put side light on (I usually do anyway) it runs just fine ! and of cause the pump stops tuning when I switch em off .
So how long do you think I can get away with this budget repair until the pump stops all together?
NOTE there is no other electric pump on this truck, not in tank, under car or anywhere.

[Mark2468]

ENGINE FAULT / SUSPECT FUEL PUMP
with reference to a previous post I thought I’d run my makeshift repair by people.
Firstly the fault, being (presumably) the diesel fuel pump.
The truck would run for a certain amount of mins, and then stop from fuel starvation.
Sometimes it would run for ten min, loose power/stop then with a bit of hand priming to save bat it would run for another ten min, and so on and so on , regardless of temperature.
Solenoids good
Fuel line good
Fuel tank and siv good
New filter
Everything as it should be but still stopped.........UNLESS! I put a gallon fuel can on engine and run two short pipes from filter housing and fuel pump in to it, then it would run all day.
SO..... I bought a small 12v generic in line fuel pump off e bay and put it just before the filter, shoved the live wire in to side lights in fuse box , and the Neg to battery terminal,
Now as long as I put side light on (I usually do anyway) it runs just fine ! and of cause the pump stops tuning when I switch em off .
So how long do you think I can get away with this budget repair until the pump stops all together?
NOTE there is no other electric pump on this truck, not in tank, under car or anywhere.

[Tyre Smoke]

I'd be inclined to wire it to an ignition fed live with an in line fuse. But apart from that, the answer is until the pump burns out. Which might be years.

[paintman]

I suspect you have a breather issue creating a vacuum in the fuel tank.
Try running it with the fuel tank cap loosened to allow air in - but be careful as we don't want diesel all over the road - & if your problem is resolved you know what the actual issue is.

[stevieturbo]

So you need to find out where the restriction is between the filter and inside the tank.

This risky bodge will not last and is not sensible.

[stevieturbo]

Does this really need two threads for the same thing ?

[Mark2468]

@paintman
Yes I have had tank off and inspected the breathers, all fine, I noticed that once off I could not pour residual fuel out through the big inlet spout, there is a kind of safety thing there, I’m guessing taking the cap off might not let air in as expected.

[Mark2468]

@stevie
I’ve had tank off, put new lines through. New filter etc, appears now to be a weak mechanical pump.