1.9 TDi PD Golf MK5 lift pump / fuel tank pump

MK5MK

Member
Joined
Dec 23, 2017
Location
mkd
TDI
1.9 BKC
Hello everybody,

I joined this forum to share my experience with my Golf MK5 1.9 TDI PD 2004 BKC, 250.000km on board.

I was always wondering if my car had a lift pump (fuel pump at the fuel tank). I never heard a buzzing sound like the one you can find in MK4 PDs.
When I changed the fuel filter, I tried to prime the engine with (diesel) fuel. I turned the ignition key on and off 5-6 times, to let the lift pump bring the diesel to the diesel fuel filter. Then I tried to start the engine. I couldn't. I tried over 15 times with starter motor running for up to 10 seconds. I opened the fuel filter housing and it was dry. I put some diesel inside the fuel filter housing, I topped it of actually and the engine started. My conclusion from that experience was that either my car has NO lift pump, or the lift pump is dead and the engine has no real use of it, it is probably just there to prime the engine and once primed the dual pump takes care the rest, in other words the engine doesn't really need the lift pump. That was 2 years ago. The car ran fine till yesterday.

Yesterday though, my car died while driving. Wouldn't restart. Would spin the starter motor for 10 seconds and the engine would start briefly and die after 5-15 seconds. I changed the lift pump and now the engine is running great again. Interesting fact: I can't hear the new pump in the cabin also. Its silent. There is no buzzing sound like in the MK4.

I am confused as my two experiences are opposite. But my latest experience is that the engine cannot run with broken lift pump. My previous experience was that the lift pump wasn't pumping (lift pump was broken or missing) but the engine was running fine.

So if your engine can't start or starts after a lot of cranking the lift pump can be a reason.


tags: lift pump, fuel pump, fuel tank pump, engine cranks won't start, engine doesn't start, dual pump, fuel filter, engine problem, 1.9 tdi, Golf MK5, BKC, diesel engine won't start.


Pictures of my old lift pump and the box from the new one. Both are Pierburg.

http://i67.tinypic.com/6fav7n.jpg
http://i64.tinypic.com/25g70ja.jpg
http://i63.tinypic.com/2hnc9dj.jpg
 
Last edited:

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
A: never run your starter for more than 3-4 seconds at a time, let it cool off for 5 seconds between starting like that.
Walbor makes a excellent fuel pump line, the intake ones as well as all the other pumps do not restrict the fuel flow if it fails. I suggest upgrading in the future.
 

MK5MK

Member
Joined
Dec 23, 2017
Location
mkd
TDI
1.9 BKC
The mechanic did a test before changing the lift pump. He put alternative fuel source to dual pump with manual hand pump, started the engine and opened lose the hose from the tank to the fuel filter housing. There was fuel coming at irregular volume rate, sometimes it would lower the fuel flow, sometimes it would stop. He said the pump is dying and can't keep up the pressure.
But two years ago that pump wasn't bringing any fuel at all, I saw it with my own eyes. How come back then the engine ran just fine?
Anyways, after we changed the lift pump, this time with the turn of key the filter was primed with fuel.

Pierburg lift pump price was 130 euro. How much is the Walbor one?
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
The tandem pump on the engine can sometimes compensate for a malfunctioning in-tank pump. I have poor hearing; so I can never hear mine, even with the rear seat raised. If the fuel filter is full, I assume that it is working properly. I took the old pump apart, and the ground brush was completely worn down.
 
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