1.9Tdi fuel filter check valve?

[Orchid70]

Hi
I have been asking this questions in every forum I can come up with - with no answers.
This is what has happened:
Im trying to get a Golf V 2007 1.9Tdi to start. It died intermittent during drive - but now it wont even start.
There are no fault codes.
Suspecting it could perhaps be the check valve in the lid on the fuel filter holder.
They are not easy to find - so Id like to find a picture on a working check valve. Any one have one, they could take a picture of (the inside of the filter holder)?
It has this number: 1K0127400K
And it is the type A.
Picture from Amazon: https://www.amazon.com/Genuine-OE-Vo.../dp/B00BIPTFKC
The day after this happened:
I have ordered a used fuel filter holder.
I can fill the fuel filter cup with fuel, with 12V directly on pump. Still couldnt start the engine yesterday.
Today I wanted to be sure the timing was correct and was ready to read measuring blocks during crank - when the bloody engine started!
Pump in tank went on when I turned ignition on, then engine started.
So I run inside to get low amp probe and SnapOn -> the tank pump was not running!
I took off the electric connector on tank pump and the engine continued to run!
I turned off the engine. Started it again, without tank pump connected.
The fuel filter holder will be run empty by the tandem pump.
Am I thinking correct here:
There must be a pressure switch in the fuel pump in the tank - that switches off when the fuel pressure is up in the fuel filter holder.
If a check valve in the filter holder lid is stuck closed - the pump in the tank will not turn on (its brand new).
But I cannot find ANY information on the check valve on a fuel filter holder modell A, where the valve is placed within the lid construction (and not the separate type placed above the lid, that can be changed separately).

The fuel pump in tank is changed and I have fitted an other used tandem pump, with the same results.
The fuel filter was changed shortly before this intermmitent engine stalling started. I checked inside the fuel filter holder couple days ago (when a friend mentioned the valve stucking for him, once he had changed filter, prohibiting him to start the engine, once the new filter house came, he could see the valve had different positions) - and could find that there was only diesel inside the filter when I lifted it up, no diesel inside the return hose or feed hose to tandem pump. When detatching the return hose, I felt there was vacuum.
So thats when I filled the filter cup with 12V directly on the tank pump. I put filter holder together and started electric pump with computer - and checked if fuel came out at tandem pump. It did. Thats when I changed tandem pump.
Activating the in-tank pump with computer only works if I have had the system open. But Im guessing that it has a pressure switch somewhere.

Here is a Autoscan - with a fault code from me disconnecting the electric connector:

Monday,16,November,2020,14:00:32:18201VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 20.4.2.0 (x64)  HEX-V2 CB: 0.4513.4
Data version: 20200730 DS317.0
www.Ross-Tech.com


Dealer/Shop Name: Firma Johannes Bruun 
Workshop Code: 000 02013 000000


VIN: WVWZZZ1KZ7W264681   License Plate: BWH469
Mileage: 263050km-163451mi   Repair Order: 






--------------------------------------------------------------------------------
--------------------------------------------------------------------------------




Chassis Type: 1K (1K0)
Scan: 01 03 08 09 15 16 17 19 25 42 44 46 52 56


VIN: WVWZZZ1KZ7W264681   Mileage: 263050km-163451miles


00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: Malfunction 0010
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: Malfunction 0010
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 03G-906-016-BKC.clb
   Part No SW: 03G 906 021 KG    HW: 03G 906 021 AN
   Component: R4 1,9L EDC  000SG  9244  
   Revision: --H07---    Serial number: VWZ7Z0G8112637
   Coding: 0000071
   Shop #: WSC 01392 785 00200
   VCID: 6E85CCE2FC9374EBB0F-803A


No fault code found.
Readiness: 0 0 0 0 1 


-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 1K0-907-379-MK70.lbl
   Part No: 1K0 907 379 P
   Component: ASR FRONT MK70      0105  
   Coding: 0017025
   Shop #: WSC 01392 785 00200
   VCID: 3FDB41A6EB79CD636B9-806A


No fault code found.


-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 1K0-820-047.lbl
   Part No SW: 1K0 820 047 FT    HW: 1K0 820 047 FT
   Component: Climatic PQ35   141 0909  
   Revision: 00141027    Serial number: 00000000000000
   Shop #: WSC 00000 000 00000
   VCID: 7BA3F5B6BFE11143071-802E


No fault code found.


-------------------------------------------------------------------------------
Address 09: Cent. Elect.        Labels:. 3C0-937-049-23-M.lbl
   Part No SW: 3C0 937 049 AD    HW: 3C0 937 049 AD
   Component: Bordnetz-SG     H52 2002  
   Revision: 00H52000    Serial number: 00000006938468
   Coding: 08890F2700041500471400001400000000097B075C0001
   Shop #: WSC 00000 785 00200
   VCID: 6B83C5F6CF8181C3971-803E


   Subsystem 1 - Part No: 1K1 955 119 E  Labels: 1KX-955-119.CLB
   Component: Wischer 180407 021  0501  
   Coding: 00038805
   Shop #: WSC 00000  


No fault code found.


-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 1K0-909-605.lbl
   Part No SW: 1K0 909 605 T    HW: 1K0 909 605 T
   Component: 37 AIRBAG VW8   020 2300  
   Revision: 05020000    Serial number: 0038PD15ZV80  
   Coding: 0013111
   Shop #: WSC 01373 785 00200
   VCID: 3D273BAEE175DF73795-8068


   Subsystem 1 - Serial number: 6332MSME177E4B65Q


   Subsystem 2 - Serial number: 6342MSME17101C600


   Subsystem 3 - Serial number: 6352QSME246D2369M


   Subsystem 4 - Serial number: 6362QSME26724D7FY


No fault code found.


-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 1K0-953-549-MY8.lbl
   Part No SW: 1K0 953 549 BB    HW: 1K0 953 549 BB
   Component: Lenksäulenmodul 036 0070  
   Coding: 0000002
   Shop #: WSC 00011 768 00200
   VCID: 73B3DD9697B159035F1-8026


No fault code found.


-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 1K0-920-xxx-17.lbl
   Part No SW: 1K0 920 853 Q    HW: 1K0 920 853 Q
   Component: KOMBIINSTRUMENT VDD 1610  
   Revision: V0003000    Serial number: VWZ7Z0G8112637
   Coding: 0003103
   Shop #: WSC 02013 222 99650
   VCID: 38292ABACE57FA5BAA3-806C


1 Fault Found:
00771 - Fuel Level Sensor (G) 
            010 - Open or Short to Plus - Intermittent
             Freeze Frame:
                    Fault Status: 00101010
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 75
                    Mileage: 263053 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 13:47:05




-------------------------------------------------------------------------------
Address 19: CAN Gateway        Labels:. 1K0-907-530-V2.clb
   Part No SW: 1K0 907 530 K    HW: 1K0 907 951 
   Component: J533__Gateway   H04 0021  
   Revision:   H04 02    Serial number: 080407F1001349
   Coding: 3D0F034007000002
   Shop #: WSC 01392 785 00200
   VCID: 2F3B11E63B193DE3FB9-807A


No fault code found.


-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 1K0-920-xxx-25.clb
   Part No SW: 1K0 920 853 Q    HW: 1K0 920 853 Q
   Component: IMMO            VDD 1610  
   Revision: V0003000    Serial number: VWZ7Z0G8112637
   Shop #: WSC 00000 000 00000
   VCID: 38292ABACE57FA5BAA3-806C


No fault code found.


-------------------------------------------------------------------------------
Address 42: Door Elect, Driver        Labels:. 1K0-959-701-MIN3.clb
   Part No SW: 1K0 959 701 M    HW: 1K0 959 701 M
   Component: Tuer-SG         005 0987  
   Coding: 0000180
   Shop #: WSC 01392 785 00200
   VCID: 38292ABACE57FA5BAA3-806C


No fault code found.


-------------------------------------------------------------------------------
Address 44: Steering Assist        Labels: 1Kx-909-144-G2V3.clb
   Part No: 1K1 909 144 L
   Component: EPS_ZFLS Kl.069 H07 1806  
   Shop #: WSC 00000 028 00001
   VCID: 34311E8AD23F1E3B86B-8060


No fault code found.


-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels:. 1K0-959-433-MIN.clb
   Part No: 1K0 959 433 CP
   Component:    KSG              0401  
   Coding: 81C802087F2D8405484BC6F010CC
   Shop #: WSC 40950 222 21286
   VCID: 0059825AD607729B523-8054


   Subsystem 1 - Part No: 1K0 951 605 C
   Component: LIN BACKUP HORN H03 1301


   Subsystem 2 - Part No: 1K0 951 178 A
   Component: Neigungssensor  003 0203


   Subsystem 3 - Part No: 1K0 951 178 A
   Component: Innenraumueberw.003 0203


No fault code found.


-------------------------------------------------------------------------------
Address 52: Door Elect, Pass.        Labels:. 1K0-959-702-MIN3.clb
   Part No SW: 1K0 959 702 M    HW: 1K0 959 702 M
   Component: Tuer-SG         005 0987  
   Coding: 0000180
   Shop #: WSC 01392 785 00200
   VCID: 392F2FBEF55DE35355D-806C


No fault code found.


-------------------------------------------------------------------------------
Address 56: Radio        Labels: 1K0-035-1xx-56.lbl
   Part No SW: 1K0 035 186 T    HW: 1K0 035 186 T
   Component: Radio BVX       034 0046  
   Revision: 00034000    Serial number: VWZ1Z2G4739028
   Coding: 0020200
   Shop #: WSC 01392 785 00200
   VCID: 372B2986C349F523A39-8062


1 Fault Found:
01044 - Control Module Incorrectly Coded 
            000 - -


End----------(Elapsed Time: 01:03, VBatt start/end: 12.6V/12.4V)-----------

[Orchid70]

My theory on some pressure valve in the filter housing was not correct. The filter house is changed.
I have been able to measure the pressure at the tandem pump now: 5 bar (72 psi) at 1500 rpm. Around 1 bar at idle.
BUT: the only time I can activate the in tank pump is, if I have had the system open (change parts) or the car has been standing for a day or two.
Then I can activate the pump with VCDS and I can start the car - again I run inside and took the SnapOn and tried to measure current on supply wire on in tank pump -> NOTHING!
Now I have to wait couple of days again to be able to activate it with the computer to see that there really is some amps from the pump....
The relay is clicking (I have tested it also) - and I have changed places with the other identical relay. So relay is not the problem.
The tank pump just wont run when the engine is on.
In VCDS, I can see that there is between 12,29-12,44V in the field "Fuel pump status" when the engine is running. Where is that voltage taken/measured from? Battery?
But the pump doesnt produce any current.
Its a brand new pump.


Any ideas?

[Roverfan]

Pump should be running when relay is energised, so the wiring to the pump and the ground path from the pump needs checking. Perhaps jump the connection at the relay so the pump runs whilst you have a wiggle around.

[Orchid70]

Pump should be running when relay is energised, so the wiring to the pump and the ground path from the pump needs checking. Perhaps jump the connection at the relay so the pump runs whilst you have a wiggle around.

I have tried to find the grounding point for the tank pump. Do YOU have an idea where it is located? Elsa does not tell what the different groun points are for - only all the locations.... and in the rear, the pictures are difficult to interpret.
Good idea on jumping the relay! Thanks - Im stuck and appreciate so VERY much your help!!

[philipharmes]

On your scan above one fault shows :-

1 Fault Found:
00771 - Fuel Level Sensor (G)
010 - Open or Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00101010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 75
Mileage: 263053 km
Time Indication: 0
Date: 2000.00.00
Time: 13:47:05

I'm guessing the fuel level sensor, which will probably be part of the " in-tank pump " mechanism uses the same earth as the pump.

I would guess the earth connection is intermittent.

[Orchid70]

Thats from me running the car without the electric connector attached to the in tank pump - sorry if I was unclear. There are NO fault codes, what so ever when the car runs out of fuel.

[philipharmes]

My fault, didn't read your post carefully enough.

Hope you get to the bottom of it.

[Crasher]

Have you checked the fuel lines are the correct way around on the pump, it is easy to get it wrong and it will run either way.

[Orchid70]

Yes they are.
Also correct at the filter.

[Roverfan]

I have tried to find the grounding point for the tank pump. Do YOU have an idea where it is located? Elsa does not tell what the different groun points are for - only all the locations.... and in the rear, the pictures are difficult to interpret.
Good idea on jumping the relay! Thanks - Im stuck and appreciate so VERY much your help!!

For the mk6 (which should be similar if not same) the ground location is given as ground connection 2 in right rear side panel, where as the ground for the fuel level sender is 'main wiring harness' so they have different grounds (5 wire fuel pump connector).
Assuming the relay is being energised the first thing to establish is whether it is a wiring problem, and then which wire. It's unlikely that you will have to find the grounding location. I'd expect any problems if any to be at the connector or close to it.
If the fault is present (pump is not running) a simple voltage/continuity test from the fuel pump connector will probably identify the offending wire. Which then can be traced back through the loom