Low fuel pressure, despite new HPFP, new fuel pressure regulator, new fuel pressor sensor ?!

[qluvr]

'24 Treg TDI with CRNB engine, 130k miles. <<< oops I meant 2013.

New HPFP installed, everything re-assembled, fuel system primed, no fuel leaks, I think every connector that matters is connected. But engine won't fire up.

Just installed a new HPFP, new Fuel Pressure regulator, and new Fuel Pressure Sender/Sensor. VCDS says it's not getting enough fuel pressure. I've meticulously primed the fuel system with VCDS every time it might possibly need it before starting. Cranking the engine strong with a new battery but it doesn't give the slightest hint of firing up.

(While I was so 'deep in the V', i put in a new turbo, new water pump, physical delete of EGR cooler. Malone stage 2 with EGR/DPR/SCR deletes both code and physical)

Any ideas? If the new HPFP is bad I might have to commit sepuku, what a long, f'ing tough job that was.

VCDS fault code is P00C6 00 (101) - Minimum Pressure Not Reached
....
engine rpm 218.50 / min
..
Mean injection quantity: 27.70 mg/stroke
...
Rail pressure regulation: status-bits 0-7: 0
Fuel High Pressure : actual value 2500 hPa <<< the fuel pressure log I started to track the engine cranking just says "2500" every time stamp, which seems odd no variation.
High fuel Pressure: specified value: 300000 hPa
Pressure control valve adaptation factor: 1.1005
Fuel leve: 21.00 I

The fuel pressure log I started has exactly 2500 pressure at every time stamp which seems odd to see zero variation.

 

[TurboABA]

Post full scan.
Your RPM is way too low.
You're not getting fuel - did you check that your filter canister is being supplied? Visually or with a pressure gauge?
Let me guess, you had lines off fuel filter canister?
I'm going to take a wild stab at it and say you incorrectly swapped the supply (marked VM) & return (marked RM) lines

 

[TurboABA]

'24 Treg TDI with CRNB engine, 130k miles.

How drunk are you? Your previous posts and VIN say you have a 2013..... now you have a Future Touareg?

 

[qluvr]

How drunk are you? Your previous posts and VIN say you have a 2013..... now you have a Future Touareg?

LOL, someone else commented on my typo that I really had a Delorean!

 

[qluvr]

Post full scan.
Your RPM is way too low.
You're not getting fuel - did you check that your filter canister is being supplied? Visually or with a pressure gauge?
Let me guess, you had lines off fuel filter canister?
I'm going to take a wild stab at it and say you incorrectly swapped the supply (marked VM) & return (marked RM) lines

o What should cranking not starting RPM be if not ~218 rpm? the cranking speed seems quite robust/normal by ear. New battery on trickle charger so lotsa juice. <<< 290 rpm is the spec I'm told.

o When I run the fuel priming cycle with VCDS commands I can hear the fuel running around, but I did check the fuel filter canister by opening it after the priming and it was full of fuel.

o I never removed the fuel lines on the filter canister when i put in a new filter, there aren't letter markings but there are blue vs white marks that match up properly on the canister and hoses on the canister lid.

o another forum person thought there was air in the fuel lines post-HPFP (which might explain the consistent 2500 pressure at all time stamps, which is likely the lowest the sensor can report) but bleeding the fuel lines is equivalent to priming the fuel system with VCDS command to run the low pressure fuel pump, which I've done consistently.

(btw before all this epic job, the engine was running normally.)

 

[TurboABA]

o What should cranking not starting RPM be if not ~218 rpm? the cranking speed seems quite robust/normal by ear. New battery on trickle charger so lotsa juice.

I don't have the specs in front of me, but that's too low.
Let's see your battery MVBs if you claim this new battery is so strong and charged.
Post a log of these as you crank too while you're at it.

o When I run the fuel priming cycle with VCDS commands I can hear the fuel running around, but I didn't check the fuel filter canister by opening it after the priming - or with a pressure gauge somehow? how to do that?

o another forum person thought there was air in the fuel lines post-HPFP but didn't mention how to bleed the fuel lines? How to do that?

You take the lid off and you follow the procedure in the service manual.

o btw before all this epic job, the engine was running normally.

 

[TurboABA]

TT 23-01-11 Date: 2001
TDI Engine, Hard Starting
In the event you have a TDI engine with the complaint of a hard start or long cranking time, check the
cranking RPM. The TDI needs a minimum of 290 RPM during cranking. If the RPM is low, check the
battery and starter system.

 

[qluvr]

You take the lid off and you follow the procedure in the service manual.

The service manual says that bleeding is equivalent to running the fuel pump (with VCDS command, which I've done meticulously every time, about 8-10 times by now), the manual does not say to take the lid off, and if I did take the lid off during priming/bleeding cycle fuel would squirt all over it seems or I misunderstand what is meant by taking lid off.
I'll try to find in VCDS how to do a log for battery "MBVs' and post result. I wonder if the starter is deficient as I'm confident in the new battery.
The battery voltage is 13.98V which seems pretty strong.

 

[TurboABA]

I didn't say take the lid off while priming....
You asked how to check if you're getting fuel into the canister.... so you either take the lid off to make sure its filled up, or you put a pressure gauge on the line as per manual.
Your battery is drained\weak. You're omitting information from what you're posting, and you're also not looking at what you're omitting.

From the other forum, your own post.

Voltage terminal 30: 10.560 V

Yup... super strong new battery on a charger with solid cranking rpm

P.S. A trickle charger is not used under these circumstance as it barely puts any current out.... you need a strong changer with some serious amps.

 

[qluvr]

OK, understood about lid, makes sense.

Just measured the new battery's voltage statically not while starting. was 13.98V so that should eliminate weak battery? which then leads to conclusion the starter is tired at only 218rpm? 290 rpm is required as you stated.
To double check the battery I'll try to find the battery log command in VCDS and log it while cranking per your suggestion. What you think of new starter as next step if battery checks out OK?
The trickle charger was for overnight. I'll be using a full charger for more crank attempts.

 

[TurboABA]

Pull these MVBs

                Address 19: CAN Gateway  (7P6 907 530 J)

  IDE00019   Voltage terminal 30 
  IDE01833-MAS03159   Battery version-Manufacturer Varta 
  IDE01833-MAS04490   Battery version-Size  
  IDE01839   Battery charge level 
  IDE01840   Battery condition for display 
  IDE01842   Usable battery charge

There's no log to find.... you select the MVBs you want to log, start the log, and then crank.

Voltage drop test starting circuit if you suspect the starter is weak.

Just measured the new battery's voltage statically not while starting. was 13.98V

Surface charge doesn't mean much if it falls off a cliff as soon as a load is applied.

 

[qluvr]

@TurboABA <<< thanks for all your advice

I double-checked the filter canister level after two consecutive 180 sec priming cycles with VCDS. The fuel level in canister was about an inch below the rim, which doesn't seem right, I manually topped it off and did a crank to check voltage log as suggested to check battery goodness. I have a full charger on the battery post set to max amps. (I only used trickle charger overnight).

The voltage log shows some serious drop to the 10V ish range (new battery, with charger hooked up). static V was 13.98 before crank and before charger hookup. Does this indicate new battery is not OK?

TIME	Loc. IDE00019
STAMP	Voltage terminal 30
	V
0.09	12.4
0.19	12.4
0.31	12.38
0.41	12.42
0.53	12.4
0.63	12.54
0.76	12.54
0.84	12.56
0.96	12.56
1.05	12.56
1.18	12.56
1.27	12.56
1.4	12.56
1.49	12.58
1.62	12.58
1.72	12.54
1.84	12.54
1.94	12.54
2.06	12.54
2.16	12.54
2.28	12.54
2.38	12.54
2.5	12.56
2.6	12.54
2.72	12.54
2.81	12.56
2.94	12.54
3.04	12.56
3.15	12.56
3.24	12.56
3.37	12.56
3.46	12.56
3.56	12.56
3.68	12.56
3.77	12.56
3.9	12.56
4	12.56
4.12	12.56
4.21	12.56
4.34	12.56
4.43	12.56
4.56	12.56
4.65	12.56
4.78	12.56
4.88	12.56
5	12.58
5.09	12.58
5.22	12.34
5.33	9.86
5.43	10.7
5.52	10.14
5.65	9.9
5.74	9.9
5.87	9.98
5.96	10
6.09	10
6.19	10.06
6.31	10.18
6.4	10.42
6.53	10.48
6.63	10.62
6.74	10.64
6.84	10.46
6.93	10.46
7.02	10.36
7.15	10.56
7.24	10.58
7.38	10.68
7.46	10.7
7.6	10.74
7.69	10.84
7.82	10.78
7.9	10.7
8.04	10.5
8.13	10.5
8.24	10.52
8.34	10.5
8.43	10.6
8.56	10.78
8.65	10.7
8.78	10.9
8.88	10.64
9	10.6
9.09	10.5
9.22	10.6
9.31	10.74
9.44	10.72
9.54	10.86
9.63	10.8
9.76	10.52
9.85	10.54
9.98	10.48
10.07	10.66
10.2	10.74
10.29	10.92
10.42	10.64
10.51	10.56
10.64	10.54
10.74	10.58
10.86	10.66
10.95	10.7
11.05	10.84
11.18	10.88
11.27	10.66
11.4	10.54
11.49	10.42
11.62	10.66
11.71	10.66
11.84	10.84
11.93	10.7
12.06	10.6
12.15	10.5
12.28	10.46
12.38	10.68
12.5	10.74
12.59	10.86
12.72	10.62
12.81	10.54
12.94	10.46
13.03	10.7
13.16	10.7
13.24	10.7
13.37	10.86
13.46	10.7
13.59	10.58
13.68	10.54
13.81	10.5
13.9	10.76
14.03	10.7
14.13	10.78
14.25	10.48
14.34	10.5
14.47	10.54
14.56	10.7
14.69	10.86
14.78	10.74
14.91	10.5
15.01	10.42
15.13	10.56
15.23	10.6
15.32	10.64
15.41	10.7
15.54	10.84
15.63	10.68
15.76	10.56
15.85	10.58
15.98	10.54
16.07	10.74
16.2	10.74
16.29	10.72
16.42	10.48
16.51	10.54
16.64	10.62
16.73	10.78
16.86	10.82
16.95	10.66
17.08	10.52
17.17	10.44
17.3	10.64
17.39	10.68
17.52	10.88
17.6	10.72
17.73	10.66
17.82	10.58
17.91	10.48
18.04	10.6
18.13	10.68
18.26	10.88
18.35	10.66
18.48	10.54
18.57	10.48
18.7	10.7
18.79	10.74
18.92	10.82
19.01	10.54
19.14	10.42
19.23	10.64
19.36	10.64
19.47	10.8
19.57	10.86
19.66	10.54
19.79	10.52
19.88	10.54
20.01	10.7
20.1	10.76
20.23	10.68
20.32	10.58
20.45	10.58
20.54	10.7
20.67	10.74
20.76	10.7
20.89	10.5
20.98	10.58
21.12	maybe this was end crank but still logging? 12.1
21.21	12.1
21.33	12.26
21.43	12.28
21.52	12.28
21.65	12.3
21.74	12.32
21.87	12.34
21.96	12.34
22.09	12.36
22.18	12.46
22.3	12.46
22.44	12.48
22.53	12.5
22.65	12.5
22.74	12.5
22.87	12.5
22.96	12.52
23.09	12.52
23.18	12.52
23.31	12.52
23.4	12.52
23.53	12.58
23.62	12.58
23.75	12.48
23.84	12.6
23.97	12.6
24.08	12.62
24.18	12.6
24.27	12.62
24.4	12.62
24.49	12.62
24.62	12.62
24.71	12.62
24.84	12.62
24.93	12.62
25.06	12.64
25.15	12.62
25.28	12.64
25.37	12.64
25.5	12.64
25.59	12.64
25.72	12.64
25.8	12.66
25.93	12.64
26.02	12.66
26.15	12.66
26.24	12.66
26.37	12.66
26.46	12.66
26.59	12

 

[qluvr]

@TurboABA
my 'charger' is seriously ancient as in decades old. I suspect it's not really functioning. Getting a new charger asap.
the new battery may be suspect?
I'll look into rpm + voltage logging after I get a new charger in an hour or so. Also will get some fuel to bump up the fuel tank from just below 1/4.

 

[qluvr]

@TurboABA

next experiment. Put my pretty new Norco 15A booster on the Treg. New logs on V, RPM.

as opposed to battery with ancient charger, the lowest V is higher with booster help, mid-11's instead of low 10's.
RPM is higher by a couple dozen RPMs but not still not achieving the 290 spec rpm.

Will try a 85A wall power (not internal battery) booster from a buddy soon. Other ideas?

The new battery sure seems suspect. May exchange it under warranty today using logs as proof. That may be the root cause of no start.

TIME	Loc. IDE00019	TIME	Loc. IDE00021	TIME	Loc. IDE01834
STAMP	Voltage terminal 30	STAMP	Engine RPM	STAMP	Battery voltage
	V		/min		mV
0.3​	13.48​	0.06​	0​	0.18​	13460​
0.62​	13.48​	0.4​	0​	0.51​	13460​
0.95​	13.48​	0.73​	0​	0.85​	13480​
1.28​	13.48​	1.06​	0​	1.18​	13480​
1.61​	13.48​	1.39​	0​	1.51​	13480​
1.93​	13.48​	1.72​	0​	1.83​	13480​
2.27​	13.5​	2.03​	0​	2.15​	13500​
2.59​	13.5​	2.37​	0​	2.49​	13500​
2.92​	13.5​	2.7​	0​	2.82​	13500​
3.25​	13.5​	3.03​	0​	3.15​	13500​
3.57​	13.5​	3.35​	0​	3.46​	13500​
3.89​	13.5​	3.68​	0​	3.79​	13500​
4.2​	13.5​	3.99​	0​	4.1​	13500​
4.54​	13.5​	4.31​	0​	4.43​	13500​
4.86​	13.52​	4.64​	0​	4.75​	13520​
5.19​	13.48​	4.96​	0​	5.08​	13480​
5.54​	13.5​	5.29​	0​	5.42​	13500​
5.88​	13.48​	5.65​	0​	5.77​	13480​
6.21​	13.5​	5.99​	0​	6.11​	13500​
6.56​	11.86​	6.31​	0​	6.44​	11420​
6.91​	11.68​	6.68​	187​	6.8​	11540​
7.21​	11.38​	7.01​	232​	7.11​	11560​
7.53​	11.54​	7.31​	233​	7.42​	11520​
7.86​	11.44​	7.64​	235​	7.76​	11440​
8.2​	11.68​	7.97​	237​	8.09​	11480​
8.53​	11.8​	8.31​	240​	8.43​	11680​
8.88​	11.58​	8.64​	250​	8.76​	11880​
9.22​	11.74​	8.99​	252​	9.11​	11680​
9.56​	11.8​	9.33​	250​	9.45​	11680​
9.89​	11.84​	9.67​	256​	9.79​	11820​
10.23​	11.52​	10​	251​	10.12​	11820​
10.56​	11.66​	10.34​	253​	10.46​	11680​
10.89​	11.66​	10.67​	250​	10.79​	11580​
11.23​	11.78​	11​	254​	11.12​	11540​
11.56​	11.66​	11.34​	251​	11.46​	11760​
11.89​	11.54​	11.67​	250​	11.79​	11720​
12.22​	11.56​	12​	256​	12.12​	11660​
12.53​	11.46​	12.32​	254​	12.43​	11580​
12.9​	11.74​	12.65​	251​	12.79​	11640​
13.28​	11.72​	13.03​	251​	13.16​	11500​
13.6​	11.72​	13.39​	253​	13.5​	11660​
13.95​	11.52​	13.71​	251​	13.83​	11660​
14.3​	11.68​	14.07​	251​	14.19​	11460​
14.65​	11.62​	14.41​	255​	14.54​	11560​
14.99​	11.42​	14.76​	253​	14.88​	11720​
15.34​	11.6​	15.1​	255​	15.22​	11500​
15.7​	11.5​	15.46​	251​	15.58​	11700​
16.02​	11.62​	15.81​	256​	15.93​	11500​
16.35​	11.64​	16.14​	252​	16.26​	11520​
16.65​	11.52​	16.45​	251​	16.55​	11560​
17​	11.54​	16.77​	251​	16.88​	11560​
17.35​	11.58​	17.12​	247​	17.24​	11680​
17.69​	11.52​	17.46​	248​	17.57​	11620​
18.04​	11.66​	17.8​	252​	17.92​	11440​
18.37​	11.72​	18.15​	254​	18.26​	11580​
18.68​	11.72​	18.47​	250​	18.57​	11580​
19​	11.7​	18.78​	251​	18.9​	11600​
19.32​	11.54​	19.11​	255​	19.22​	11680​
19.67​	11.52​	19.44​	253​	19.56​	11620​
20.02​	11.68​	19.79​	253​	19.9​	11500​
20.32​	11.6​	20.12​	257​	20.21​	11500​
20.63​	11.62​	20.42​	255​	20.54​	11540​
20.97​	11.64​	20.75​	256​	20.86​	11620​
21.34​	11.6​	21.09​	258​	21.22​	11440​
21.65​	11.56​	21.45​	257​	21.55​	11440​
21.96​	11.58​	21.75​	255​	21.87​	11440​
22.31​	11.38​	22.07​	256​	22.2​	11640​
22.66​	12.52​	22.42​	258​	22.54​	11420​
23.02​	12.7​	22.78​	107​	22.9​	12680​
23.37​	12.74​	23.14​	23​	23.27​	12720​
23.7​	12.88​	23.47​	0​	23.59​	12700​
24.03​	12.9​	23.81​	0​	23.92​	12900​
24.37​	12.94​	24.14​	0​	24.27​	12920​
24.71​	12.94​	24.49​	0​	24.61​	12940​
25.03​	13.02​	24.81​	0​	24.93​	12960​
25.36​	13.04​	25.14​	0​	25.25​	13020​
25.69​	13.04​	25.47​	0​	25.58​	13060​
26.04​	13.06​	25.79​	0​	25.91​	13060​
26.37​	13.08​	26.14​	0​	26.27​	13080​
26.68​	13.1​	26.46​	0​	26.57​	13100​
27​	13.12​	26.78​	0​	26.89​	13120​
27.32​	13.14​	27.11​	0​	27.22​	13120​
27.67​	13.14​	27.44​	0​	27.55​	13140​
28.01​	13.16​	27.78​	0​	27.9​	13140​
28.35​	13.16​	28.12​	0​	28.25​	13160​
28.68​	13.18​	28.46​	0​	28.58​	13160​
29.04​	13.2​	28.79​	0​	28.92​	13180​
29.37​	13.2​	29.14​	0​	29.26​	13200​
29.67​	13.22​	29.46​	0​	29.56​	13200​
29.96​	13.22​	29.76​	0​	29.86​	13220​

 

[qluvr]

@TurboABA next experiment. Put my pretty new Norco 10A booster on the Treg. New logs on V, RPM.

as opposed to battery with ancient charger, the lowest V is higher with booster help, mid-11's instead of low 10's.
RPM is higher by a couple dozen RPMs but not still not achieving the 290 spec rpm.

Will try a much more powerful booster from a buddy soon. Other ideas? Another suggestion was to take off serpentine belt temporarily to try to get over the 290 rpm hurdle

The new battery sure seems suspect. May exchange it under warranty today using logs as proof.

TIME	Loc. IDE00019	TIME	Loc. IDE00021	TIME	Loc. IDE01834
STAMP	Voltage terminal 30	STAMP	Engine RPM	STAMP	Battery voltage
	V		/min		mV
0.3	13.48	0.06	0	0.18	13460
0.62	13.48	0.4	0	0.51	13460
0.95	13.48	0.73	0	0.85	13480
1.28	13.48	1.06	0	1.18	13480
1.61	13.48	1.39	0	1.51	13480
1.93	13.48	1.72	0	1.83	13480
2.27	13.5	2.03	0	2.15	13500
2.59	13.5	2.37	0	2.49	13500
2.92	13.5	2.7	0	2.82	13500
3.25	13.5	3.03	0	3.15	13500
3.57	13.5	3.35	0	3.46	13500
3.89	13.5	3.68	0	3.79	13500
4.2	13.5	3.99	0	4.1	13500
4.54	13.5	4.31	0	4.43	13500
4.86	13.52	4.64	0	4.75	13520
5.19	13.48	4.96	0	5.08	13480
5.54	13.5	5.29	0	5.42	13500
5.88	13.48	5.65	0	5.77	13480
6.21	13.5	5.99	0	6.11	13500
6.56	11.86	6.31	0	6.44	11420
6.91	11.68	6.68	187	6.8	11540
7.21	11.38	7.01	232	7.11	11560
7.53	11.54	7.31	233	7.42	11520
7.86	11.44	7.64	235	7.76	11440
8.2	11.68	7.97	237	8.09	11480
8.53	11.8	8.31	240	8.43	11680
8.88	11.58	8.64	250	8.76	11880
9.22	11.74	8.99	252	9.11	11680
9.56	11.8	9.33	250	9.45	11680
9.89	11.84	9.67	256	9.79	11820
10.23	11.52	10	251	10.12	11820
10.56	11.66	10.34	253	10.46	11680
10.89	11.66	10.67	250	10.79	11580
11.23	11.78	11	254	11.12	11540
11.56	11.66	11.34	251	11.46	11760
11.89	11.54	11.67	250	11.79	11720
12.22	11.56	12	256	12.12	11660
12.53	11.46	12.32	254	12.43	11580
12.9	11.74	12.65	251	12.79	11640
13.28	11.72	13.03	251	13.16	11500
13.6	11.72	13.39	253	13.5	11660
13.95	11.52	13.71	251	13.83	11660
14.3	11.68	14.07	251	14.19	11460
14.65	11.62	14.41	255	14.54	11560
14.99	11.42	14.76	253	14.88	11720
15.34	11.6	15.1	255	15.22	11500
15.7	11.5	15.46	251	15.58	11700
16.02	11.62	15.81	256	15.93	11500
16.35	11.64	16.14	252	16.26	11520
16.65	11.52	16.45	251	16.55	11560
17	11.54	16.77	251	16.88	11560
17.35	11.58	17.12	247	17.24	11680
17.69	11.52	17.46	248	17.57	11620
18.04	11.66	17.8	252	17.92	11440
18.37	11.72	18.15	254	18.26	11580
18.68	11.72	18.47	250	18.57	11580
19	11.7	18.78	251	18.9	11600
19.32	11.54	19.11	255	19.22	11680
19.67	11.52	19.44	253	19.56	11620
20.02	11.68	19.79	253	19.9	11500
20.32	11.6	20.12	257	20.21	11500
20.63	11.62	20.42	255	20.54	11540
20.97	11.64	20.75	256	20.86	11620
21.34	11.6	21.09	258	21.22	11440
21.65	11.56	21.45	257	21.55	11440
21.96	11.58	21.75	255	21.87	11440
22.31	11.38	22.07	256	22.2	11640
22.66	12.52	22.42	258	22.54	11420
23.02	12.7	22.78	107	22.9	12680
23.37	12.74	23.14	23	23.27	12720
23.7	12.88	23.47	0	23.59	12700
24.03	12.9	23.81	0	23.92	12900
24.37	12.94	24.14	0	24.27	12920
24.71	12.94	24.49	0	24.61	12940
25.03	13.02	24.81	0	24.93	12960
25.36	13.04	25.14	0	25.25	13020
25.69	13.04	25.47	0	25.58	13060
26.04	13.06	25.79	0	25.91	13060
26.37	13.08	26.14	0	26.27	13080
26.68	13.1	26.46	0	26.57	13100
27	13.12	26.78	0	26.89	13120
27.32	13.14	27.11	0	27.22	13120
27.67	13.14	27.44	0	27.55	13140
28.01	13.16	27.78	0	27.9	13140
28.35	13.16	28.12	0	28.25	13160
28.68	13.18	28.46	0	28.58	13160
29.04	13.2	28.79	0	28.92	13180
29.37	13.2	29.14	0	29.26	13200
29.67	13.22	29.46	0	29.56	13200
29.96	13.22	29.76	0	29.86	13220

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[TurboABA]

Yup... Need more juice... You're almost there

 

[qluvr]

@TurboABA


well, the latest experiment which should have been awesome, actually went backwards!

Installed a new OEM battery from the stealership. Bought a new high-end charger/wall-power-starter unit (schumacher SC1307). Charged the battery from 45% to 100% after a few hours. Cleared codes, ran fuel priming cycle, set up logs. Set the wall-powered starter which is an 85A assist. Cranked it.

Result: worse voltage and RPMs than last time! I'm dumbfounded and feeling hopeless.
The full scan showed exactly the same as above with the usual low fuel pressure code.
Maybe a bad battery/voltage controller of some kind?
Any ideas?
There was a suggestion to remove the serpentine belt to maybe get over the 290 rpm threshold but haven't tried that yet, hardly a permanent solution though it could eliminate some causes like fuel system causes if it started, so I'll try that tomorrow am.

Logs:

TAMP	Engine RPM	STAMP	Fuel high-pressure: actual value	STAMP	Rail pressure regulation: status-Bits 0-7	STAMP	Battery voltage
	/min		hPa				mV
0.17​	0​	0.28​	2500​	0.39​	0​	0.06​	12840​
0.6​	0​	0.72​	2500​	0.83​	0​	0.5​	12840​
1.05​	0​	1.17​	2500​	1.29​	0​	0.94​	12980​
1.52​	0​	1.64​	2500​	1.75​	0​	1.42​	12840​
1.96​	0​	2.08​	2500​	2.19​	0​	1.86​	12840​
2.4​	0​	2.52​	2500​	2.65​	0​	2.29​	12920​
2.88​	0​	3.01​	2500​	3.14​	0​	2.76​	12800​
3.37​	116​	3.48​	2500​	3.62​	0​	3.25​	9280​
3.83​	182​	3.96​	2500​	4.08​	0​	3.73​	9900​
4.32​	190​	4.43​	2500​	4.54​	0​	4.21​	9780​
4.76​	190​	4.87​	2500​	4.98​	0​	4.66​	9680​
5.2​	194​	5.32​	2500​	5.43​	0​	5.09​	9840​
5.64​	207​	5.76​	2500​	5.88​	0​	5.54​	10700​
6.1​	217​	6.22​	2500​	6.32​	0​	6​	10680​
6.53​	219​	6.66​	2500​	6.77​	0​	6.44​	10420​
6.99​	219​	7.12​	2500​	7.23​	0​	6.88​	10500​
7.47​	218​	7.58​	2500​	7.71​	0​	7.34​	10420​
7.92​	218​	8.04​	2500​	8.16​	0​	7.82​	10720​
8.36​	218​	8.48​	2500​	8.59​	0​	8.27​	10560​
8.83​	219​	8.95​	2500​	9.08​	0​	8.73​	10640​
9.3​	219​	9.4​	2500​	9.52​	0​	9.2​	10500​
9.73​	218​	9.86​	2500​	9.96​	0​	9.64​	10500​
10.18​	219​	10.29​	2500​	10.42​	0​	10.07​	10360​
10.65​	219​	10.77​	2500​	10.9​	0​	10.53​	10420​
11.12​	217​	11.24​	2500​	11.36​	0​	11.01​	10280​
11.57​	216​	11.68​	2500​	11.8​	0​	11.46​	10200​
12.05​	217​	12.16​	2500​	12.28​	0​	11.93​	10140​
12.52​	218​	12.62​	2500​	12.73​	0​	12.42​	10300​
12.96​	211​	13.08​	2500​	13.19​	0​	12.84​	10000​
13.41​	215​	13.54​	2500​	13.66​	0​	13.3​	10340​
13.89​	218​	14.02​	2500​	14.13​	0​	13.78​	10140​
14.37​	218​	14.48​	2500​	14.6​	0​	14.25​	10200​
14.83​	220​	14.96​	2500​	15.09​	0​	14.72​	10280​
15.3​	220​	15.4​	2500​	15.51​	0​	15.2​	10340​
15.73​	220​	15.84​	2500​	15.97​	0​	15.62​	10200​
16.21​	220​	16.33​	2500​	16.45​	0​	16.1​	10260​
16.7​	220​	16.83​	2500​	16.93​	0​	16.58​	10460​
17.14​	221​	17.26​	2500​	17.37​	0​	17.04​	10340​
17.58​	222​	17.7​	2500​	17.82​	0​	17.48​	10460​
18.03​	222​	18.15​	2500​	18.26​	0​	17.93​	10440​
18.49​	221​	18.62​	2500​	18.72​	0​	18.38​	10500​
18.94​	178​	19.04​	2500​	19.15​	7​	18.83​	11720​
19.36​	53​	19.48​	2500​	19.59​	7​	19.26​	12140​
19.81​	0​	19.93​	2500​	20.04​	7​	19.71​	12260​
20.25​	0​	20.38​	2500​	20.49​	7​	20.15​	12500​
20.71​	0​	20.83​	2500​	20.93​	7​	20.61​	12560​
21.16​	0​	21.28​	2500​	21.4​	7​	21.06​	12600​
26​	July	2023​	19:16:46:16025-VCID:372B3AD25FCE6D22FE1-8062	VCDS Version: Release 23.3.1 (x64)	Data version: 20230421 DS346.2
ADVMB	3.0TDI FSA X20 0013
	G004	F0	G025	F0	G197	F0	G349
TIME	Loc. IDE00021	TIME	Loc. IDE00188	TIME	Loc. IDE01834	TIME	Loc. IDE04016
STAMP	Engine RPM	STAMP	Fuel high-pressure: actual value	STAMP	Battery voltage	STAMP	Fuel Pressure Regulation
	/min		hPa		mV
0.06​	0​	0.19​	2500​	0.31​	12580​	0.43​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
0.54​	0​	0.65​	2500​	0.76​	12580​	0.89​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
0.99​	0​	1.11​	2500​	1.23​	12580​	1.34​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
1.44​	0​	1.56​	2500​	1.69​	12600​	1.82​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
1.93​	0​	2.04​	2500​	2.15​	12540​	2.26​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
2.36​	0​	2.48​	2500​	2.59​	12540​	2.7​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
2.8​	0​	2.92​	2500​	3.04​	12540​	3.15​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
3.27​	104​	3.39​	2500​	3.52​	10100​	3.64​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
3.76​	184​	3.88​	2500​	4​	9480​	4.13​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
4.24​	189​	4.35​	2500​	4.46​	9480​	4.57​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
4.67​	190​	4.79​	2500​	4.9​	9560​	5.01​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
5.11​	197​	5.24​	2500​	5.36​	9380​	5.48​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
5.6​	205​	5.72​	2500​	5.85​	9920​	5.96​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
6.06​	213​	6.18​	2500​	6.29​	10260​	6.4​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
6.5​	217​	6.62​	2500​	6.73​	10100​	6.83​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
6.94​	218​	7.06​	2500​	7.18​	10180​	7.29​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
7.39​	219​	7.51​	2500​	7.62​	10020​	7.73​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
7.83​	220​	7.95​	2500​	8.08​	10100​	8.19​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
8.31​	221​	8.44​	2500​	8.55​	10140​	8.66​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
8.76​	219​	8.87​	2500​	8.98​	9940​	9.09​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
9.19​	221​	9.31​	2500​	9.44​	10100​	9.57​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
9.68​	221​	9.79​	2500​	9.9​	10180​	10​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
10.11​	222​	10.23​	2500​	10.34​	10120​	10.47​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
10.58​	222​	10.7​	2500​	10.83​	10240​	10.96​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
11.07​	222​	11.19​	2500​	11.32​	9960​	11.44​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
11.56​	223​	11.69​	2500​	11.82​	10300​	11.93​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
12.06​	221​	12.15​	2500​	12.26​	10260​	12.37​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
12.47​	222​	12.59​	2500​	12.72​	10280​	12.85​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
12.96​	222​	13.08​	2500​	13.2​	10240​	13.32​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
13.43​	223​	13.55​	2500​	13.66​	10060​	13.77​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
13.87​	224​	13.98​	2500​	14.09​	10200​	14.2​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
14.3​	223​	14.42​	2500​	14.55​	10180​	14.67​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
14.77​	222​	14.89​	2500​	15.02​	10020​	15.15​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
15.25​	222​	15.37​	2500​	15.48​	10160​	15.59​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
15.68​	223​	15.79​	2500​	15.9​	10160​	16​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
16.11​	224​	16.23​	2500​	16.34​	10180​	16.45​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
16.55​	222​	16.67​	2500​	16.8​	10060​	16.91​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
17.02​	223​	17.14​	2500​	17.26​	10000​	17.37​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
17.49​	223​	17.61​	2500​	17.74​	10140​	17.85​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
17.95​	222​	18.07​	2500​	18.18​	10140​	18.29​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
18.39​	223​	18.51​	2500​	18.62​	10100​	18.72​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
18.83​	223​	18.96​	2500​	19.08​	10080​	19.21​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
19.31​	224​	19.43​	2500​	19.54​	10200​	19.65​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
19.75​	224​	19.87​	2500​	19.98​	10160​	20.09​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
20.19​	224​	20.32​	2500​	20.44​	10300​	20.55​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
20.65​	223​	20.76​	2500​	20.87​	10220​	20.97​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
21.08​	224​	21.2​	2500​	21.31​	10020​	21.43​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
21.55​	223​	21.67​	2500​	21.78​	10120​	21.9​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
22.02​	224​	22.14​	2500​	22.26​	10100​	22.36​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
22.47​	224​	22.59​	2500​	22.7​	10220​	22.81​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
22.91​	224​	23.03​	2500​	23.16​	10100​	23.28​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
23.38​	222​	23.5​	2500​	23.62​	9920​	23.72​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
23.83​	223​	23.93​	2500​	24.04​	10260​	24.14​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
24.25​	222​	24.38​	2500​	24.5​	10160​	24.62​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
24.74​	223​	24.86​	2500​	24.99​	10120​	25.11​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
25.21​	223​	25.33​	2500​	25.44​	10160​	25.54​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
25.65​	224​	25.76​	2500​	25.87​	9940​	25.97​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
26.08​	224​	26.2​	2500​	26.31​	9920​	26.42​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
26.52​	222​	26.64​	2500​	26.77​	9940​	26.88​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
27​	222​	27.12​	2500​	27.23​	10080​	27.33​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
27.44​	222​	27.56​	2500​	27.69​	10200​	27.8​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
27.91​	224​	28.04​	2500​	28.16​	10160​	28.26​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
28.37​	130​	28.48​	2500​	28.59​	11880​	28.69​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
28.8​	25​	28.92​	2500​	29.04​	11900​	29.15​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
29.27​	0​	29.39​	2500​	29.52​	11960​	29.63​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
29.74​	0​	29.86​	2500​	29.99​	12280​	30.1​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
30.2​	0​	30.31​	2500​	30.42​	12060​	30.52​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
30.63​	0​	30.75​	2500​	30.88​	12360​	30.99​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
31.11​	0​	31.22​	2500​	31.35​	12160​	31.46​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
31.57​	0​	31.69​	2500​	31.82​	12320​	31.93​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
32.04​	0​	32.15​	2500​	32.26​	12200​	32.36​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
32.47​	0​	32.59​	2500​	32.7​	12180​	32.8​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa
32.91​	0​	33.03​	2500​	33.15​	12200​	33.26​	FRP CMD:30000/--- kPa / FRP ACT:250/--- kPa

 

[PRY4SNO]

Result: worse voltage and RPMs than last time! I'm dumbfounded and feeling hopeless.

Have you looked into any of your wiring? Might be worth checking some harness connectors and fuses/relays.

Also, it's very possible I misread your post, but if you were opening the fuel filter canister after priming it (and not re-priming) you were going backwards. The act of opening it can potentially incorporate air. All one needs to do is run the pump to prime the fuel system for about 30 seconds, once or twice (wait about 20-30 seconds between cycles to allow the pump to cool down), and it's good to go so long as there were no leaks.

 

[qluvr]

Have you looked into any of your wiring? Might be worth checking some harness connectors and fuses/relays.

Also, it's very possible I misread your post, but if you were opening the fuel filter canister after priming it (and not re-priming) you were going backwards. The act of opening it can potentially incorporate air. All one needs to do is run the pump to prime the fuel system for about 30 seconds, once or twice (wait about 20-30 seconds between cycles to allow the pump to cool down), and it's good to go so long as there were no leaks.

I've checked all the connectors that were touched during the HPFP/turbo R&R. Good idea to check fuses, will do tomorrow.
Every single time I do a crank I always use VCDS to run the low pressure pump to prime the fuel system, and I can hear the pump and hear the gurgles in the engine compartment (180 secs per the manual). Sometimes I've run the priming cycle twice for extra assurance.

Still wondering if there's a faulty electronics part somewhere that's limiting voltage during cranking. I'm totally mystified how the 85A wall-powered starter function of the schumacher charger/starter unit and a new-today fully charged OEM battery is being defeated down to 10V.

 

[TurboABA]

If you hear "gurgles", what does that tell you?

 

[oilhammer]

Bad taco?

 

[qluvr]

If you hear "gurgles", what does that tell you?

haha, air bubbles perhaps, but the only solution I know of is the factory recco priming cycle, which I've done >20 times, sometimes twice ie every time before I try a crank. What other ideas for purging air from the fuel system? Gurgle might not be the right word for what I'm hearing, don't know a 'smoother' sound word, hissing maybe more like it.


1. When others open their filter canister, is the fuel level exactly at the top, or 1 inch below the top like mine? A mech friend suggested I get a pressure measuring kit at an auto parts store and measure the supply line into the fuel canister - maybe the low pressure fuel pump is underperforming, but that can have nothing to do with too low voltage cranking, the root symptom of non-starting.

2. To prime the fuel system in VCDS, I'm choosing:
Select Control Module > Engine > Output Values > Fuel Pump Electronics > Start (after putting in 180 secs per the manual recco duration). Then I can hear the pump whine in ~5-second pulses for a minute or so. When I listen in the engine compartment I can hear fuel moving around. I pulled the injectors fuel return line on the passenger side rail and there was plenty of fuel in that hose line.
This morning I plan to loosen an injector high pressure supply line nut, wrap a rag around it, prime and crank and see if the rag gets wet.

I'm still so puzzled that new yesterday 100% charged OEM battery bolstered with 85A wall-powered starter are only delivering ~10V and sub-290 RPMs during crank. It seems impossible unless there's some faulty voltage regulating electronics module? that's constraining the battery/starter-boost. Whatever that low voltage electrical root cause is, is likely the culprit.

 

[qluvr]

l listened carefully to the last priming session. No gurgles at all, just some faint whining sounds. The injector fuel return line had plenty of fuel in it.

well, the wife is really pissed off for not having her beloved Treg to go to the Oregon beach, so I'm packing our Golf R to go and won't be testing/trying anything till return on Saturday.
Huge thanks to all for hanging in there on a puzzling situation with an amateur mech.

 

[oilhammer]

Reminds me of a fellow here with the username "FixUntilBroke" , LOL.

I wish I had some silver bullet for you.

 

[pedroYUL]

@TurboABA <<< thanks for all your advice

I double-checked the filter canister level after two consecutive 180 sec priming cycles with VCDS. The fuel level in canister was about an inch below the rim, which doesn't seem right...

The heck is not right, 3 min of the lift pump running should absolutely fill the filter canister to the brim. Are you absolutely sure fuel hoses are in their right position?

Maybe there is a pinched hose in that new lift pump.

 

[oilhammer]

Or maybe it's just out of fuel.

 

[TurboABA]

He was low on fuel according to the scan.... about 1/5 full.... he was told to add more to the tank just in case.
I'm starting to suspect the N276 not being energized at this point.... he should log it's values.
I know it's "a new part" but it wouldn't be the first time a new part is broken.... or maybe it's connector is off or not properly engaged.

 

[qluvr]

The heck is not right, 3 min of the lift pump running should absolutely fill the filter canister to the brim. Are you absolutely sure fuel hoses are in their right position? Maybe there is a pinched hose in that new lift pump.

On the filter canister I never removed the hoses and they aren't kinked. Haven't touched the LP fuel pump. Just got a fuel pressure measuring kit to test the LP fuel supply hose at the filter canister.

Or maybe it's just out of fuel.

Also added 8 gallons to put the tank fuller than a mere 1/4 tank in case the LP fuel pump wasn't getting enough cooling.

He was low on fuel according to the scan.... about 1/5 full.... he was told to add more to the tank just in case.
I'm starting to suspect the N276 not being energized at this point.... he should log it's values.
I know it's "a new part" but it wouldn't be the first time a new part is broken.... or maybe it's connector is off or not properly engaged.

I'll try to find if there's a N276 logging function in VCDS. I inspected the connector - the wires look good, no bent pins, 'snaps' nicely into place.

 

[pedroYUL]

The lift pump needs to provide pressure, but also volume. Did you test both?

 

[qluvr]

The lift pump needs to provide pressure, but also volume. Did you test both?

Today I tried checking the pressure with a rented kit - at the supply hose to filter canister, but the fuel (from priming cycle) won't go past the instrument's T fitting to enable a pressure reading, despite depressing the relief valve next to the gauge to let air out of the tester's lines. need to figure that out. When I pulled the supply hose off the T, there was a "POP" of pressure and some fuel came out. I've never used a pressure tester before - See attached pressure measure setup photo. The LP pressure spec is 4 bar (58psi) when the instrument's thru valve is open or 6 bar (87 psi) when the instrument's thru valve is closed. My setup in the picture is like the thru valve closed, so should be the latter 6 bar target.
Sunday edit. Tried again with another size adapter hose, the pump is def putting out fuel, at 1.3L per 30 seconds when I did a volume test. Supposed to be 1.7L but maybe that's while running the engine, vs the pulsing of VCDS priming cycle, or vs a more continuous priming mode of a VW tech's VW scanner. Fuel is filling the filter canister and fuel is getting all the way to the injectors' return lines.

Looks like to check volume (tomorrow's task) I should do a priming cycle for 30 secs while diverting the filter canister supply hose into a measuring container. The spec is 1.7 L/30 seconds.

BTW - I know that fuel is getting primed all the way to the fuel rails even with 1 minute max priming, because the injectors' fuel return lines had plenty of fuel when I pulled one of the connectors on that hose line. 2nd evidence: Had fuel squirting like crazy between the two nuts on a faulty 1st replacement HP fuel regulator when I cranked. (A 2nd replacement regulator didn't leak.)

I still don't know why the priming won't obey a 180 seconds command. The LP pump only goes 60 secs regardless so I have to do multiple primes to get to spec. Weird. I added fuel to the tank to get it to 1/2 tank to be extra sure the LP fuel pump is covered/cooled.