Air in fuel line

Have noticed that cranking time is getting longer and longer for my 2002 diesel Westminster. It does start eventually and then runs fine.
Its been back to the garage, not a main stealer but a trusted local, and they have identified the above. They have replaced fuel filter and feed pipe[which was going porous they say], but still no joy. Have also been spraying all joints etc with a leak detector spray, but nothing found.
Garage reckon that its gonna be difficult [and possibly expensive] to trace as air gets in but no fuel leaking out.
The diesel pump was reconditioned about 2 years ago and has done about 30k miles since then. Surely it doesn't need another overhaul...cost me a packet last time.
Any ideas or suggestions gratefully received.

Mine did that run back. I added a bit of clear pipe before filter when it was cold and glowplugs were on you could see the fuel run up then after 20secs or so when the in tank pump stoped it would run back. I added a 1 way valve after the filter it still did the same. 2 new filters and o rings it did the same. Did away with the filter casing and put an inline filter insted as i had to hand no fuel run back no sucking air when starting. Picked up a filter casing and filter and left the clear pipe before filter and havent had a problem since

Whilst air in the fuel line is not good don't get blinkered. Are your glow plugs reasonably new, good quality and are they all (or at least 4) firing?
Are the injector leak-off pipes good and secure?
Have you checked your in-tank pump?
Is there any difference in the amount of cranking required depending on the amount of fuel in the tank?
In the 'how to' section at the top of here you'll find one write up on checking the pump flow and another on gaining access to it through the floor if you don't want to drop the tank.

Oh and welcome to the Loony Bin - nice car, shame about the Gaylander.

Check that lift pump is working and giving good flow.

I had air in fuel line when lift pump (in tank pump) stopped working ,and twice when the leak off pipe at the return union on the rear of diesel pump had a tiny hair line split in it .and no fuel leaks..

stustrong -thanks for your experience, sounds very much like mine.
What did you do about the electronics in the fuel filter housing.
What in line filter did you use?

thanks to others also...much food for thought

Garage did check the leak off pipes and renewed one of them and also checked connections and then leak sprayed them, so I think that seems OK.

Pump in tank appears to be working OK according to my garage, but heyho I may need to be checking it out physically, just don't fancy doing it that's all, but will have to bite the bullet sometime!

any other 'solutions' out there?

Garage replaced one leak off pipe ,change the lot dont mess about there easy to do and cheep, and often the cause of air.

enaitch said:

stustrong -thanks for your experience, sounds very much like mine.
What did you do about the electronics in the fuel filter housing.
What in line filter did you use?

thanks to others also...much food for thought

Garage did check the leak off pipes and renewed one of them and also checked connections and then leak sprayed them, so I think that seems OK.

Pump in tank appears to be working OK according to my garage, but heyho I may need to be checking it out physically, just don't fancy doing it that's all, but will have to bite the bullet sometime!

any other 'solutions' out there?

Click to expand...

I just did it as it was all i had to hand. Ran it for two days like that until new items came from dealers i just left eletrics pluged in

enaitch said:

stustrong -thanks for your experience, sounds very much like mine.
What did you do about the electronics in the fuel filter housing.
What in line filter did you use?

thanks to others also...much food for thought

Garage did check the leak off pipes and renewed one of them and also checked connections and then leak sprayed them, so I think that seems OK.

Pump in tank appears to be working OK according to my garage, but heyho I may need to be checking it out physically, just don't fancy doing it that's all, but will have to bite the bullet sometime!

any other 'solutions' out there?

Click to expand...

Do the check for flow and function as detailed in the "How To" section. Only time you can get air in the clear pipe is if the lift pump is shot and air is being sucked in by the action of the pressure pump in the injection pump. Usually past the O'rings on the inlet and outlet pipes in the filter head. But also maybe from a split feed pipe in the tank. If the lift pump is running air cannot be sucked in only fuel can leak out. On your model lift pump should run with glow lamps, when engine is running or on cranking. Genuine lift pumps have a NRV in them which stops any fuel back drain. The after market ones don't or at least the one i got doesn't. And that was a VDO unit. So maybe fitting an NRV in the line near the filter would be a good move if anyone has one of the aftermarket lift pumps. Also maybe if it is getting hard to start hot get it on diag and look at the modulation. Static timing maybe out. Or if the problem is there cold glow plugs maybe duff. You need good plugs on at least three consecutively firing cylinders to get any sort of a start cold.

Thanks all
Plenty to be getting on with.
I knew joining this forum was a good move!

When mine did the same it was glow plugs

Strange as it may seem my diesel failed to start today. Had a look, air in clear pipe. Spill pipe from number one injector to injection pump split. Fitted new one and also an NRV before filter because my new lift pump does not have one. All good now.

When mine did that you could watch the diesel flow up but in tank pump would stop and diesel wasn't actually all the way to the diesel pump. My in tank pump dosent have a nrv and no diesel runs back overnight now.

stustrong said:

When mine did that you could watch the diesel flow up but in tank pump would stop and diesel wasn't actually all the way to the diesel pump. My in tank pump dosent have a nrv and no diesel runs back overnight now.

Click to expand...

It may do if you get a leak in any part of the system after the injection pump. In 1999 lift pump on cranking was introduced. Before that lift pump only ran with glow lamp on or when engine was running. This helped with hot starting problems. But possibly because of this aftermarket lift pumps don't have the NRV the genuine pumps had. Sat level and with a reasonable amount of fuel in the tank fuel should not run back anyway but if you park with the arse end down a slope and you get a pin hole in a spill pipe it may do. NRV was peanuts on eBay.

8MM 5/16" ONE WAY ALUMINIUM NON RETURN CHECK VALVE PETROL DIESEL OIL WATER | eBay

Don't know if it will apply to yours but ended up being my problem. I had new seals on the FIP, New Leak-over pipes, New injector (No.4) with sensor, Non return valve prior to filter.
No fuel leaking anywhere, New inline lift pump fitted, but still the air! (Would run but kept breaking down, and got harder and harder to start!) fitted Hot start fix, to enable glowplugs constantly.....(timed unit)..... Still air!
Eventually changed in tank liftpump! Bingo! No air!
What had happened, Mushroom growing in return section of unit, extra suction created caused pinhole rusting on metal pipes at bends prior to connectors to plastic fuel lines!
Messy job, but can check brake lines at same time!
Moral:-
Do it properly first time!
Hope this helps

Troyyz said:

Don't know if it will apply to yours but ended up being my problem. I had new seals on the FIP, New Leak-over pipes, New injector (No.4) with sensor, Non return valve prior to filter.
No fuel leaking anywhere, New inline lift pump fitted, but still the air! (Would run but kept breaking down, and got harder and harder to start!) fitted Hot start fix, to enable glowplugs constantly.....(timed unit)..... Still air!
Eventually changed in tank liftpump! Bingo! No air!
What had happened, Mushroom growing in return section of unit, extra suction created caused pinhole rusting on metal pipes at bends prior to connectors to plastic fuel lines!
Messy job, but can check brake lines at same time!
Moral:-
Do it properly first time!
Hope this helps

Click to expand...

Are you replying to OP? If so quote him.

wammers said:

Are you replying to OP? If so quote him.

Click to expand...

Sorry, was just trying to help!
Still learning myself

Troyyz said:

Sorry, was just trying to help!
Still learning myself

Click to expand...

No problem, but it helps if it's known who you are answering. Your point is valid.

wammers said:

It may do if you get a leak in any part of the system after the injection pump. In 1999 lift pump on cranking was introduced. Before that lift pump only ran with glow lamp on or when engine was running. This helped with hot starting problems. But possibly because of this aftermarket lift pumps don't have the NRV the genuine pumps had. Sat level and with a reasonable amount of fuel in the tank fuel should not run back anyway but if you park with the arse end down a slope and you get a pin hole in a spill pipe it may do. NRV was peanuts on eBay.

8MM 5/16" ONE WAY ALUMINIUM NON RETURN CHECK VALVE PETROL DIESEL OIL WATER | eBay

Click to expand...

I had one of them nrvs its sat in the little box of spanners and screwdrivers in the boot now. My old transporter was a sod with the slightest of air in the system as it used the inj pump as a suction pump too. Even with my dodgy parking at the farm and fuel light on never had a run back. I used a little bit of two stroke oil in the tank to pink the diesel so it was easier to see what was going on. 1st flick of the key would take fuel just past filter and a quick flick onto 2nd preheat then just as gplug lamp went out crank and it fired straight up cold. Hot starts not so good haha.