The Mitsubishi Pajero Owners Club®

mjc506

Morning all,

Had this issue for a little while, and running out of ideas...

When we've less than 1/4 tank fuel left, a going down longish steepish downhill results in rough running, a loud fuel pump, and eventually the engine cuts out and we coast to a stop (losing power steering and servo brakes). Once stopped, the engine will crank for a few seconds before firing, and then it runs a little rough with a noisy fuel pump until a short while after we fill up again. If we keep our foot on the throttle a little down the hill it seems to help prevent stalling.

The rough running is a lower than normal idle - once the revs are up it runs fine, aside from being able to hear the fuel pump. The issue never happens if we've more than ~1/4 tank of fuel.

I think this sounds like fuel starvation? In my minds eye I can imagine the fuel pickup at the back of the tank, all the fuel sloshing forward when going downhill, resulting in no fuel to the engine, but I know the shogun fuel tank is a little better designed than that... Laughing

I've pulled the access plate under the seats, and lifted the fuel pickup. The filter looked ok, and I could see a yellow 'bucket' thing fixed in the tank - I presume this is part of the surge tank arrangement? I did see a very small amount of water in the bottom, consistent with 13 years of condensation! but the tank/fuel looked otherwise clean inside.

There are no diesel leaks evident, and I have not yet dropped the tank. I've not been able to reproduce the issue going uphill.

Does anyone have a diagram or cross-section of the tank showing the breather and pickup locations, and internal structure? And more importantly I suppose, any ideas of things to check?

Thanks,

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peteinchad · Posted: Sat Jun 17, 2017 9:52 Post subject:

The bottom of the tank hasn't been dented I assume.

mjc506 · Posted: Sat Jun 17, 2017 12:52 Post subject:

Nope, I've pulled the black plastic protector thing off, and all looks ok.

peteinchad · Posted: Sat Jun 17, 2017 13:45 Post subject:

Has the fuel pickup pipe in the tank got a pinhole leak about 1/4 of the way up from the filter. If so then it will pull fuel though until the level gets below the hole - it will then suck air and no fuel

mjc506 · Posted: Sat Jun 17, 2017 13:51 Post subject:

I'll pull it and have a proper look thumbright

radiomike · Posted: Sat Jun 17, 2017 14:16 Post subject:

I would be more concerned about the loss of brakes as they are not reliant on the engine running.

mjc506 · Posted: Sat Jun 17, 2017 15:15 Post subject:

It's not a complete loss, just the added help from the hbb fades fairly quickly after the engine dies. Especially noticeable as it always happens on a downhill, and of course you lose engine braking too.

SteveW-DID · ***** Joined: 04 Jun 2006 Posts: 826 Location: Dorset

Fuel pump likely to be on its way out.

SteveW-DID · ***** Joined: 04 Jun 2006 Posts: 826 Location: Dorset

You may get around the issue temporarily by fitting an electric lift pump.

mof000 · Posted: Sun Jun 18, 2017 10:48 Post subject:

Oh dear..... There are some recon units on eBay although i know nothing about the company that do them?
http://www.ebay.co.uk/itm/Shogun-Pajero-Diesel-Pump-109144-3062-109144-3050-ME190711-ME204338-4m41-3-2DiD-/262988505817?hash=item3d3b5622d9:g:7mQAAOSwv0tVChIU

They are not cheap.. Just out of interest, have you taken a look at your fuel filler pipes?

mjc506 · Posted: Sun Jun 18, 2017 20:52 Post subject:

Could well be the pump, coming up to 250k miles. Crying or Very sad

Would I expect problems under load as well? I've not had chance to pull the top of the tank off to check the pickup pipes, fingers crossed!

Fuel filler pipes aren't in the best condition, but they're far from rusted through. I do know that there's no crud in the bottom of the tank.

I'll report back with what I find.

mof000 · Posted: Sun Jun 18, 2017 21:16 Post subject:

Fingers crossed for you Bud. I hope there is a better and cheaper fix for the old Gal!

mjc506 · Posted: Sun May 06, 2018 23:09 Post subject:

Sorry for the slight delay... The other half put in 5ltrs of unleaded by mistake... since then I've been unable to replicate the fault!

I'll take that as a fix haha Laughing

Perhaps it cleaned some gunk out from somewhere.

assassin · Posted: Mon May 07, 2018 2:44 Post subject:

Fuel pick up pipe, or, if it has the plastic filter on the end it has rotted and acting like a valve and cutting fuel in certain positions.

Remove the inspection hatch inside the vehicle, soak well for several days before with penetrating oil, remove the fuel head and inspect the pick up pipe, they are usually pitted so clean it fully with wet and dry paper wet and remove all the rust, examine any pitted area and look for pin holes, if you have one or two and they are at the lower end of the pick up pipe you can either solder them after cleaning the pipe internally, with a sweating iron or you can cover the pick up pipe with heat shrink tubing and shrink it down and trim off any excess.

If you have the plastic filter on the end of the pick up pipe them leave it off as they deteriorate over time, but you will need to clean out the tank and you do this by syphoning out the majority of the fuel through the hole until you have removed the majority of it and then remove the drain plug underneath the tank to remove the rest.
Flush the tank out with a hosepipe and catch everything which comes out, there will often be a lot of crud, and note how much crud comes out, dry the tank off by blowing inside it with a hair dryer or place a halogen light under the tank in close proximity to it to warm it up to dry it out.

Strain the fuel you have removed so you remove all the crud from your strained fuel, put this back into the tank and note how much crud has been removed, bleed the fuel system and start the vehicle and run for a couple of days and then replace the fuel filter.

mjc506 · Posted: Mon May 07, 2018 9:17 Post subject:

I like the heatshrink idea!

The inside of the tank is clean, almost worryingly so (perhaps the previous owner had some issues. There's also no drain plug, so likely to be an aftermarket tank?) I'd already removed the in tank filter, which had collapsed in on itself, indicating that it had become blocked.

Of course, should the fault reappear, the next stage is reinspecting the pickup pipes, and/or dropping the tank to get a proper look inside!