P38A Chasing Gremlins

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Bix

Bix

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Full Member
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3,673
Location
Yeovil
Howdy howdy howdy,

It seems whenever I fix one problem I get a new one show up the next day.

So today's fault appears to be fuel related, but I can't figure what, If I have more than 3/4 of a tank, absolutely no issue what so ever. But once it drops lower than that, if I leave the bus overnight I have to reprime the system as fuel seems to flow back into the tank. But only when I drop below 3/4 of a tank.

It has got a newish in tank pump (IIRC, I changed that 2 years ago), and the FIP was changed last year (I think). I do not appear to have any fuel leaks, which is why I assume it is rolling back into the pump. I have read about folks putting in one way valves as fix when the in tank pump isn't a genuine LR part. But are there other areas to look before going down that route?

Thanks in advance.
 
Diesel?

I fitted a one way valve but I'd be checking the leak off valves or somewhere up that way to see if there is air getting in allowing it to flow back. Odd that the level of the tank matters.
 
Grrrrrr said:
Diesel?

I fitted a one way valve but I'd be checking the leak off valves or somewhere up that way to see if there is air getting in allowing it to flow back. Odd that the level of the tank matters.
Click to expand...
Aye, a dirty diesel. I've seen a few people have if they have aftermarket in tank pumps because their one way valves aren't any good. But I am sure I have a factory in tank pump. Unfortunately my local LR dealership sells Britpart parts now because they can't get hold of genuine parts that easily anymore.

Just drove into town and the other half mentioned she could smell diesel (my sense of smell is getting dulled so I hadn't noticed), upon popping the bonnet I notice some of the spill off pipes were wet, in the case of injector 1, enough to now have fuel pooling and running down the side of the block. I'll get the spill off pipe replaced and see if that makes a difference. I don't know how it could, but worth a punt I suppose.

5 of the injectors were rebuilt when the FIP was with injector 4 being replaced with new. So I hope they aren't leaking.

Saint.V8 said:
Bix rocks an oil burner.....

If I may was the pump a genuine OEM pump or an aftermarket? No stigma in AM pumps, but they are known to fail with frequency!
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The FIP was rebuilt at a local specialist who the BMW dealership sends their work to. The in tank pump was purchased via the local LR dealers, but I can't remember if it was a genuine part or not, as mentioned above.
 
Bix said:
Aye, a dirty diesel. I've seen a few people have if they have aftermarket in tank pumps because their one way valves aren't any good. But I am sure I have a factory in tank pump. Unfortunately my local LR dealership sells Britpart parts now because they can't get hold of genuine parts that easily anymore.

Just drove into town and the other half mentioned she could smell diesel (my sense of smell is getting dulled so I hadn't noticed), upon popping the bonnet I notice some of the spill off pipes were wet, in the case of injector 1, enough to now have fuel pooling and running down the side of the block. I'll get the spill off pipe replaced and see if that makes a difference. I don't know how it could, but worth a punt I suppose.

5 of the injectors were rebuilt when the FIP was with injector 4 being replaced with new. So I hope they aren't leaking.


The FIP was rebuilt at a local specialist who the BMW dealership sends their work to. The in tank pump was purchased via the local LR dealers, but I can't remember if it was a genuine part or not, as mentioned above.
Click to expand...
Leaking Spill pipes can allow air into the system and this can cause the fuel in the line to drain bak to the tank if the NRV is poop. As the fuel system is supposed to be closed loop, if all is well, when the fuel tries to drain back the lower pressure as it tries to draw a vacuum will prevent this (mostly) from draining back to the tank - like a straw in a drink, put your finger over the end you can lift it out of drink and the straw remains full until you take your finger off - so if you have leaky spill pipes, this can allow air into the system and allow the fuel to drain back.

Also, who is your local dealer? I use Hunters of Guildford and not had a problem with them!
 
Sorry, meant to say spill / leak off pipes. Don't know where I got spill valves from - betwixt and between on Saint's issues!

My in-tank pump is OEM but most definitely not Britpart. It has no non-return valve. Don't think it matters on later (post 99 models) as they pump while cranking but mine is too old to.
 
Grrrrrr said:
Sorry, meant to say spill / leak off pipes. Don't know where I got spill valves from - betwixt and between on Saint's issues!

My in-tank pump is OEM but most definitely not Britpart. It has no non-return valve. Don't think it matters on later (post 99 models) as they pump while cranking but mine is too old to.
Click to expand...

Just so, even the VDO OEM pump does not have an NRV anymore. Possibly because of the pump whilst cranking 1999 and on as you say. But at least if the lift pump fails the car will still start and run, albeit with slightly reduced power on hills etc. If the original lift pump with the NRV in it packs up the car is going nowhere, because the injection pump whilst it can suck fuel from the tank without an NRV in the lift pump it can't with one.
 
Saint.V8 said:
Leaking Spill pipes can allow air into the system and this can cause the fuel in the line to drain bak to the tank if the NRV is poop. As the fuel system is supposed to be closed loop, if all is well, when the fuel tries to drain back the lower pressure as it tries to draw a vacuum will prevent this (mostly) from draining back to the tank - like a straw in a drink, put your finger over the end you can lift it out of drink and the straw remains full until you take your finger off - so if you have leaky spill pipes, this can allow air into the system and allow the fuel to drain back.

Also, who is your local dealer? I use Hunters of Guildford and not had a problem with them!
Click to expand...
Ahh, I get you, I'll order some new spill off pipe and change it all. Looks like it is all original, so well overdue replacement.

I used the one in Pickering as that was where I have had the majority of my work carried out. Although I really need to find somewhere a bit closer to home now.
 
Heatshrink or cable tie the ends of the pipes, helps to keep them in place and last longer, had to replace mine several times till I did that and no probs since.
 
Grrrrrr said:
You need proper Bosch stuff. The cheap stuff will fail within 6 months. Ask @tomcat59alan! Even he had to break open his wallet in the end.
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I went for whatever it is Europarts sell, I don't even remember what it cost, but I was able to buy it and fit it in their carpark. About 1.5m of the stuff was needed, and now she starts like a champion again. Now all I have to do is clean up the oil patch on the floor caused by diesel washing it off of the side of the block.
 
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