DiD NT Fuel Starvation Thread - In tank Filter

[erad]

Obviously, the in-tank filter is rather heavily blocked with gunk. When you start the engine, the fuel pump draws a full flow of fuel, using only what the engine needs and returning the rest back to the tank. The losses occurring in the in-tank filter are high enough that the pressure in the fuel line (in the engine bay at least) is going below atmospheric, and you are sucking some air into the fuel system. The engine stops. By filling the tank to over half full, you are bringing the overall pressure in the engine bay and the main filter to enough so that the air leak is not enough to stop the engine. Clean the in-tank filter and your problems should hopefully go away.

[bennyb29]

Obviously, the in-tank filter is rather heavily blocked with gunk. When you start the engine, the fuel pump draws a full flow of fuel, using only what the engine needs and returning the rest back to the tank. The losses occurring in the in-tank filter are high enough that the pressure in the fuel line (in the engine bay at least) is going below atmospheric, and you are sucking some air into the fuel system. The engine stops. By filling the tank to over half full, you are bringing the overall pressure in the engine bay and the main filter to enough so that the air leak is not enough to stop the engine. Clean the in-tank filter and your problems should hopefully go away.

Thanks a lot for the explanation. Made it very clear to someone not as technically informed as myself. I will ensure the fuel is kept at a safe level to avoid this happening, and till I have the parts with me and ready to embark on this as a DIY. I admit I have never ventured to such DIYs in the past, but this forum and members have been inspirational.

[erad]

The losses may not all be in the in-tank filter. Your main fuel filter could be blocked to the point where the pressure falls once past this filter. The easiest one to check is the main filter. If it hasn't been replaced for a while, get a new one and do that. Your problems may go away. If they still persist, then it has to be the in-tank filter. Access to this requires you to lift the second row seat and undo a hatch on the right side of the car. Then you get access to the fuel tank and another hatch.


If you are having troubles now, even going up a steep hill could cause fuel starvation because the filter is mounted above the fuel tank level, and going uphill, the difference becomes even greater. Check for hardened or split hoses around your fuel filter, and if they are bad, replace the hoses. Hopefully this will minimise air leaks then. Finding air leaks is very difficult, so it is best to examine the components and replace them if they are suspect.

[bennyb29]

The losses may not all be in the in-tank filter. Your main fuel filter could be blocked to the point where the pressure falls once past this filter. The easiest one to check is the main filter. If it hasn't been replaced for a while, get a new one and do that. Your problems may go away. If they still persist, then it has to be the in-tank filter. Access to this requires you to lift the second row seat and undo a hatch on the right side of the car. Then you get access to the fuel tank and another hatch.

This video will be my guide to replacing the in-tank filter.

https://www.youtube.com/watch?v=OIZfAAFbA6Q&list=LLVdQaat9M230JRSKxfRDP9Q&index=2&t=0s

If you are having troubles now, even going up a steep hill could cause fuel starvation because the filter is mounted above the fuel tank level, and going uphill, the difference becomes even greater. Check for hardened or split hoses around your fuel filter, and if they are bad, replace the hoses. Hopefully this will minimise air leaks then. Finding air leaks is very difficult, so it is best to examine the components and replace them if they are suspect.

The main fuel filter has been replaced as part of scheduled servicing, however i am certain the in-fuel filter is usually forgotten. Also, the symptoms i face are exactly as described by others on this thread previously, hence the added focus on that being the solution. The car runs perfectly otherwise.

[erad]

That video is fantastic. I ope that I never have to get in there to replace mine, but now I know what to expect.

[wazznt]

What about the diesel bacteria for blocked suction filters ? ,I have had problems in off road vehicles and it can cause no end of fuel suction and filter issues ..

[bennyb29]

Replaced the in-tank fuel filter on my Pajero over the weekend. The bolts on the metallic fuel cap were an absolute PITA to remove owing to rust(??) and dirt. Some WD40 helped on some of them, but a couple of the bolts sheared off. Wonder what i am going to do about those now.

Fuel filter is replaced and i wont be topping up the tank this time before i get to the 1/4 mark, to check if the original starvation issue has been resolved.

[swys42]

Replaced the in-tank fuel filter on my Pajero over the weekend. The bolts on the metallic fuel cap were an absolute PITA to remove owing to rust(??) and dirt. Some WD40 helped on some of them, but a couple of the bolts sheared off. Wonder what i am going to do about those now.

Fuel filter is replaced and i wont be topping up the tank this time before i get to the 1/4 mark, to check if the original starvation issue has been resolved.

I also did mine last month but it wasnt near as dirty as yours. How many k's have you done? Lots of country fill ups? Do you use any Additives like CEM ?

[bennyb29]

I also did mine last month but it wasnt near as dirty as yours. How many k's have you done? Lots of country fill ups? Do you use any Additives like CEM ?

My car has now done 200,600 kms as of this morning, and is a 2010 model. Evidently, this filter was never replaced in the last 10 years.
In the past 5 years since i had the car, most of the fuel fills have been from metro regions. Ofcourse, there have been the couple of outback trips, plus the interstate runs. I don't use any additives at all, so not sure if that's a reason.

[bennyb29]

To update this thread:
After replacing the in-tank fuel filter on my car, the fuel starvation issue i had as described on this thread has been resolved.

[BruceandBobbi]

To update this thread:
After replacing the in-tank fuel filter on my car, the fuel starvation issue i had as described on this thread has been resolved.

Seems to be very hit and miss withe the in tank filter. 337,000 on ours and still with the original filter. We never use no name fuel and always use Caltex Vortex or BP Ultra. Used Shell once and it ran like a dog, so never again.

[erad]

It is probably a good idea to use a fuel additive which prevents fungus buildup in the tank. It will prevent the fungus from forming and if you already have it on the filter, it will probably help to dissolve the fungus, thereby eliminating the need to get into the tank a nd replace the filter.

[bennyb29]

Seems to be very hit and miss withe the in tank filter. 337,000 on ours and still with the original filter. We never use no name fuel and always use Caltex Vortex or BP Ultra. Used Shell once and it ran like a dog, so never again.

I am not the first owner of my car, so not sure about what servos the first owner used for close to 90ks before i got it.
I usually stick to Caltex or Costco diesel.

Reading other comments, l realise i don't use any fuel additives, so not sure if that's a contributor.

[BruceandBobbi]

Always have used additives Benny.

[JHwick]

Been reading this thread and wondering if the in-tank filter is the cause of the issues on my MY15 NX...

Runs fine and doesn't stall while driving but I every now and then it won't start.
Sounds like fuel starvation; cranks but doesn't kick over.

Pump the primer on the main filter and it feels like there's no diesel in the line.
Keep pumping until it gets harder to press, crank the engine and away it goes as if there was nothing wrong.

Already replaced the main filter but it didn't change anything.
Kinda sounds like a filter blockage and priming the pump gets it going, so maybe the tank filter is to blame
Would just replace it if it was a quick and easy job but accessing the tank sounds like an epic.

Any thoughts on whether this is likely to be the cause?
If it's not the issue, maybe I've got a leak somewhere that's causing the fuel line to empty but I can't see or smell any diesel leaks...