TDI Lift Pump (BKD) - What should the flow rate be?

[-mike-]

Hi all,

 

Having some issues with the car lately after it had all rollers / rockers replaced and other bits and pieces done (first garage did shoddy repair on tensioner when I had the belt changed....(stud) and it failed.... you can guess the rest). The car doesn't seem as eager as it was even post head work, and I recall when it was in for some work at the dealer that the technician said at the time that the in tank fuel pump was borderline. Today I decided to take the in tank pump out, clean the gauze and show it some love (repair valvetrain garage didn't replace tandem pump gasket initially and well......... things got oily!). I thought I'd try a flow test for the lift pump and ran it for thirty seconds. I was able to get it to pump 1.3 litres in that 30 seconds, and whilst I can't find much else bar one site online, that site suggests the pump should return 3+ litres a minute. Does anyone know if this is correct? If so, it puts me at 2.6 litres for a minute run and presumably under specification?

 

Any help much appreciated, thank you.

[J.R.]

They are probably feeding you a red herring if its the same garage that did the head work, first port of call would be the cam timing, specifically the Torsion Value using something like VCDS.

[-mike-]

Hey,

 

The garage that did the head repair and fitted new cambelt etc was an independent. The torsion value is currently -2.9 which is where it was when the dealer did the belt six or so years ago. I haven't been tempted to adjust this yet, but have been advised a value slightly positive is best for best power.

 

The lift pump was noted as weak when the main dealer replaced the tandem pump under warranty or as the tech put it ‘borderline’ but not replaceable under warranty as still deemed ok. The reason I’m now looking at the in tank pump is that after the independent doing the head work and associated parts, they never replaced the tandem pump gasket which resulted in a whole lot of oil in the fuel, filter and tank. The screen on the lift pump was pretty grotty.

 

I realise the mix of independent and main dealer is confusing in my ramblings so I apologise, hopefully this will help:

1) main dealer replaced tandem pump and said lift pump borderline.

2) independent 1 did timing belt and stripped threads. Didn’t use the stud Vw supply to fix this problem and instead fitted some contraption of a bolt and bodged the repair. 18 months later bolt sheared at 70mph. Independent didn’t want to know.

3) independent 2 who did the head work. Didn’t replace tandem pump gasket when repairing car. Replaced when I had running issues and showed him fuel filter black. Job was quoted to be around the cost of replacement second hand engine fitted but ended up being double - had i known it would cost so much I would have opted for a replacement engine. The fact that I knew how the car had been driven and serviced for the last 60k miles made me opt to fix the current lump.
 

I have no faith in the car but still love the stupid thing. 
 

thanks again for your time and reply 

Edited 17 August, 2023 by -mike-

[-mike-]

I should add, this is where I got flow values from (tdi club)

2005 BEW PD lift pump operation and internals | TDIClub Forums

PD_fuel_delivery_check.pdf (tdiclub.com)

[TheClient]

I'm not sure to be honest. I can see the 3lpm mentioned in your link and I found another forum guide that mentioned 3lpm plus.

 

However, looking at a few replacement lift pumps the specs seem to vary. The few that provide flow, I saw some variation from 2.42lpm to 3.6lpm. Which is quite a divergence and would put your lift pump bang on the lower spec, if correct and acceptable. 

 

The other thing that is likely important is pressure, have you tested bypass pressure with a guage?

 

Re flow rate spec -  all I can think of is you need a vw repair guide to list it for mk5 golf or Oct ii bkd. Maybe Google will find something uploaded online. Or you could pay for 1 hour erwin access assuming they still have historic guides from that period available.

 

Sounds like a right nightmare with repair shortcuts. That's why I like to do everything I can myself. At least I know what shortcuts I've taken, if any.  

 

Do replacement studs come with the belt kit, I thought I recall seeing some do? 

[-mike-]

21 hours ago, TheClient said:

I'm not sure to be honest. I can see the 3lpm mentioned in your link and I found another forum guide that mentioned 3lpm plus.

 

However, looking at a few replacement lift pumps the specs seem to vary. The few that provide flow, I saw some variation from 2.42lpm to 3.6lpm. Which is quite a divergence and would put your lift pump bang on the lower spec, if correct and acceptable. 

 

The other thing that is likely important is pressure, have you tested bypass pressure with a guage?

 

Re flow rate spec -  all I can think of is you need a vw repair guide to list it for mk5 golf or Oct ii bkd. Maybe Google will find something uploaded online. Or you could pay for 1 hour erwin access assuming they still have historic guides from that period available.

 

Sounds like a right nightmare with repair shortcuts. That's why I like to do everything I can myself. At least I know what shortcuts I've taken, if any.  

 

Do replacement studs come with the belt kit, I thought I recall seeing some do? 

They do indeed come with the kit, only he pulled the thread in the head fitting the stud. Then decided rather than getting the oversized stud that is available for such an issue, he'd fit a bolt. This bolt also was left at full length and the cambelt cover had a slit cut in it so that it slid over the bolt......... I've never seen a bodge quite like it! Haven't tested pressure yet, I don't have a gauge but I can see if I can borrow/beg/steal one I guess!  

 

Thanks for your help