Fuel air bubble - tdi

MOI

MOI

A2OC Donor
Just replaced a fuel hose on my a2 tdi after the old one was perished and leaking.
I then started the car to check the leaking had stopped and the car started fine.
But after a couple of mins of idling the engine cut out and the DIS reported a fuel warning.
So I assume what’s happened here is that air bubble has entered the fuel system.
If this is the case how can I bleed it out?

Thanks
Mo
 
Can’t say exactly which but it was about 8in long with plugs either side. One green one black. Positioned about a foot from the rear drivers side door.
 
Well that's a fair way from the front so I would say crank away and rrev like a banshee once it starts. It takes 4-8 attempts just changing a pip le at the front...
 
MOI said:
Just replaced a fuel hose on my a2 tdi after the old one was perished and leaking.
I then started the car to check the leaking had stopped and the car started fine.
But after a couple of mins of idling the engine cut out and the DIS reported a fuel warning.
So I assume what’s happened here is that air bubble has entered the fuel system.
If this is the case how can I bleed it out?

Thanks
Mo
Click to expand...
Hi MOI,
It sounds like you had a lot of air enter the pipe work , you would be better putting a vacuum pump on the fuel line in the engine bay & pulling the diesel up to the pump , that would protect the starter motor from excessive cranking & burning out! !
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Keep a sharp eye for very high temps on starter & wiring

Just protect hoses from any spills .
Hope that helps
Keith.
 
Last edited:
Hmm just tried the cranking with an additional battery attached but no dice. Called green flag and the mechanics said its a fuel pump issue. Now being recovered to a local garage. #A2Life
 
Oh dear, at least it will get sorted, could be crud in the lifter pump from tank? Odd that it ran though, does sound like air only to me. Feed back what happens!
 
Ah green flag. Bet he was listening for the sound of an electric pump. THERE IS NONE.....

you have air locked the feed pipe and that needs to be vacuumed to draw the fuel into the tandem pump. Do not just crank the engine as the chance of killing the battery and / or the starter is very high. Remove the RETURN line from the tandem then vacuum the fuel from the tank, through the filter and up the line in to the tandem and into the internal fuel manifold and back out the return to tank port.

Need to ensure all pipes are good condition and all connections and filter drain are air tight. Wasting your time if not.
 
Agree with @audifan above. All I would add is sometimes you can have a lot of vacuum on the return line that appears to suck nothing. If you get a helper to crank the starter while the vacuum is in place you will then see all the froth and air come out as it splutters into life. A bit late now as it's gone to the garage but might help someone else reading this.
 
Nice day for it. It’s with garage now. Will feed back.

9076BA3C-1FAF-4EEB-9461-624C96E41DF3.jpeg
 
Beware the garage might just try cranking it and flatten/damage the battery. You may not know about it until a cold morning and the car wont start.

Last time my A2 had the filter changed by a indy garage they flattened the battery and had to put it on charge overnight. I reckon my battery is damaged now and it wasn't that old :( The garage should have known better.
 
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Every time the battery is discharged damage is done and it never recovers. The more often it happens the shorter the battery life...

Personally would not even like to see a garage try to crank it on a professional charger as that will cook the battery very quickly. The vacuum method is the only safe way of doing it.
 
Ok so problem fixed and largely self inflicted. Let me explain.

On Monday I was in Warrington when I noticed the smell of fuel. Taking a look under the car I could see dripping. I quickly refuelled and drove back to manchester and decided to let by br-in-law take a look.

He found a split fuel hose as per image. He thought he could fix it so we popped over to Halfords (only place open at that time) and bought some hose for £6. He then replaced it. Car then started but chocked out and despite numerous attempts the following morning it refused to start and had to be taken to seen by a green flag mechanic (who wrongly diagnosed a fuel pump failure) and then taken to a garage.

I’ve just picked up the car and was told the replacement hose had dislodged. I assume this meant the plug stayed in but the hose detached from it. He had to scramble around his spare parts to find a suitable hose as they aren’t available anymore. Anyway new hose is in and car now running smoothly again. Cost: £60
 

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