Diesel runs back to fuel tank.

[zocker]

Greetings and thanks to all for providing the forum and help.

I have just bought a 406 Diesel, the previous owner tells me that if the vehicle is left without use for three days the diesel will have run back to the fuel tank and that it will require priming with the hand pump. Does anyone know what the solution to this problem might be?

Thanks in advance


Zocker

[john170277]

could have a leaky fuel filter housing check all around for any signs of diesel escaping

[Doggy]

I agree, it's almost certainly a minor leak somewhere - it does help if you add a few more details about your car, as there are quite a few different diesel engines fitted to 406's

Welcome to the site BTW

[john170277]

I agree, it's almost certainly a minor leak somewhere - it does help if you add a few more details about your car, as there are quite a few different diesel engines fitted to 406's

Welcome to the site BTW

i had same problem on my hdi that was due to me not tightening the top of the filter housing properly

[gordonw]

Its caused by losing vacuum from the system to hold the fuel in the pump and it runs back to the tank over time check all pipes/connections up to the pump or get a garage to check the vacuum/suction for you if thats ok its the fuel lift pump that not working properly.A diesel leak should be easy to see but i think you would have discovered it if that had been the cause by now.

[zocker]

Thanks all! and thanks for the welcome!

All I know about the engine is that it is 1905 cc. I cannot see any other idenntifying info on the engine itself, they didnt think to put a label on it says its make model etc- When the weather clears, I'll take up your suggestions.

Thanks again

zocker

[Doggy]

Right! 1905cc identifies it as a 1.9TD, (as distinct from the 2.1 made at the same time & later 90/110/136 bhp HDi's).

As everyone & his dog has already said, you need to check the fuel filter lid's on securely, seal properly in place etc. The fuel filter also has a drain tap on the bottom to let the water out - make sure it's properly closed too. Any loose/dodgy fuel pipes in the engine bay could be your culprit too.

Failing all that, your car doesn't have a lift pump, but does have a removeable in-tank strainer / level sensor accesible from under the driver's side back seat cushion. Sometimes, these get blocked up and impede fuel flow. The priming bulb should feel firm - if it goes soft / collapses it's a sure sign of a blocked strainer.

Hope that lot helps.

Ooooh loook! fore fahsand posts.

[lozz]

Doggys a post Whore

[gumby6371]

Ill fitting or perished leak off pipes will have the same affect, I am speaking from experience , for the princely sum of £5 get yourself a length of pipe from your local factors and change all of them, make sure you've got some long nose pliers for refitting as a couple have rather tight fiddly access.
It's worth checking each joint on the fuel pipe in the engine bay. when I bought mine the garage had changed a perished priming bulb but never nipped up the jubilee clip holding the pipe on, you could actually hear the air bubling back into the system.
As already mentioned the fuel filter housing can also be a culprit, take the top off and make sure the seal is good then tighten back down.

In short follow the fuel pipe and each time you hit a joint or component check it's not leaking and it's sealing properly, unfortunately air will sneak in a gap too small for diesel to come out of so you wont neccesarily see spilt fuel at the offending place.

If it's a very small/slow leak do what I did for 6 months, let the plug light go out, turn it off, let the plug light go out again, then fire it up, the fuel pump will prime it for you
NOTE - not a long term solution unless you're really busy (lazy) like me

[Bailes1992]

Prime the system so the granade goes hard, then carry on squeezing it.
If theres a ny leaks you should be able to see them under pressure

Change the fuel filter and the leak off pipes to start with though. You can do it for less than a tenner.