low fuel pressure after HPFP replacement?!? advice?

quattroluvr · Jul 26, 2023

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

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.

rgh0 · Jul 26, 2023

The 2500 hPa is probably as low as the system reads hence the consistent reading. You may still have air in the system after the HPFP in the lines to the injectors and regulating valve have you bled these lines ?

quattroluvr · Jul 26, 2023

OH, I hope to the bottom of my heart that it's air in the lines! (not a faulty new HPFP!) How do you bleed the air out?? <<< the manual says bleeding is = to what I've been doing already meticulously, i.e. priming the fuel system with VCDS command to run the low pressure pump for 180 secs. BTDT.

Brendanm · Jul 26, 2023

Why did you replace the hpfp?

quattroluvr · Jul 26, 2023

Preventive maintenance: 130K miles and wanted to avoid a catastrophic failure of the HPFP, which much reading of forums indicates can happen as few as 80K miles but more often when it happens is around very roughly 130K miles. Plus I had to do the tedious job of exposing the 'V' anyway to replace the leaking coolant valve next to the oil cooler . Since the turbo had to come out to replace the HPFP I replaced it too and it did indeed have excessive shaft play.

SaVAGeSoot · Jul 26, 2023

Post full scan.

quattroluvr · Jul 26, 2023

Address 01: Engine (J623-CNRB) Labels:. 059-907-401-V2.clb
Part No SW: 7P0 907 401 K HW: 7P0 907 401 K
Component: 3.0TDI FSA X20 0013
Revision: 56X20--- CVN: EE3A38FB38D3FF8238D3FF820E1FC39E
Coding: 292A4012233600050000
Shop #: WSC 23069 444 00000
ASAM Dataset: EV_ECM30TDI0117P0907401K 001014
ROD: EV_ECM30TDI0117P0907401K.rod
VCID: 372B3AD25FCE6D22FE1-8062
VINID: 9E65D58094A00D45000421010C1030B1FB

1 Fault Found:
21233 - High Pressure Fuel Rail
P00C6 00 [101] - Minimum Pressure Not Reached
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 209298 km
Date: 2023.07.25
Time: 06:33:10

Engine RPM: 218.50 /min
Normed load value: 100.0 %
Vehicle speed: 0 km/h
Coolant temperature: 29 °C
Intake air temperature: 29 °C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 10.560 V
Unlearning counter according OBD: 40
Fuel temperature: 24.9 °C
Mean injection quantity: 27.70 mg/stroke
Rail pressure regulation: status-Bits 0-7: 0
Fuel high-pressure: actual value: 2500 hPa
High fuel pressure: specified value: 300000 hPa
Pressure control valve adaptation factor: 1.1005
Fuel level: 21.00 l

Readiness: 0 0 0 1 X

SaVAGeSoot · Jul 26, 2023

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

Also, post pic of DeLorean!

volkswagens-for-life · Jul 26, 2023

rofl OP replaces known good HPFP and the new one doesn't work. ****in classic.

OP - did you fill the fuel canister all the way up? Preferably with Diesel Purge?

quattroluvr · Jul 26, 2023

volkswagens-for-life said:
OP - did you fill the fuel canister all the way up? Preferably with Diesel Purge?

The service manual says to prime/bleed the fuel system with VCDS command, which I've done numerous times and should fill the canister - I'l remove the lid to check. What's "Diesel Purge"? something you put in fuel tank?

SaVAGeSoot · Jul 26, 2023

His crank rpm is too low, his battery is drained, he doesn't listen.... who knows what other crap he's butchered when doing all this PM (read bricking a previously working engine)

quattroluvr · Jul 26, 2023

I'll try listening better! The new battery's voltage is 13.98V currently. I'll replace the trickle charger with a full charger for trying more than occasional cranks. The cranking RPM is indeed too low, at 218 rpm vs 290 rpm min required. Maybe the starter is tired? I'll also look in VCDS for a battery log function if there is one, during cranking and post that.

I'll also try Dannyboy's suggestion on priming more and cranking more in bursts.

SaVAGeSoot · Jul 26, 2023

Your fuel level isn't ideal. Make sure that filter canister is getting fuel.
You need more RPM..... remove the belt off the front of the engine to see if that gives you a little less resistance\load when cranking to get the RPM over the minimum requirement (maybe your alternator or water pump is junk, etc)
If still No Go, Voltage drop test the starting system....

SaVAGeSoot · Jul 26, 2023

I'm gonna suspect you're gonna ask about the voltage drop thing next, so I'll just leave this here

https://static.nhtsa.gov/odi/tsbs/2020/MC-10174460-0001.pdf

https://sep.turbifycdn.com/ty/cdn/yhst-44365514171686/alternator-starter-testing-safety-voltage-drop-testing.pdf

quattroluvr · Jul 26, 2023

@SaVAGeSoot @volkswagens-for-life

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	12.66
26.68	12.66

SaVAGeSoot · Jul 26, 2023

Your voltage drop is massive for whatever reason.
Add RPM to the log as well if possible.
Read my last 2 posts..... I gave you lots of suggestions

SaVAGeSoot · Jul 26, 2023

Let's see this "charger" that you have on the terminals as you're cranking....

quattroluvr · Jul 26, 2023

yah, this 'charger' is seriously ancient as in decades old. I'm going to get a new one per your pointing it out.

volkswagens-for-life · Jul 26, 2023

Let us know what you find out.

Good luck w/ the Purge - its great stuff.

SaVAGeSoot · Jul 26, 2023

10A is not sufficient for this scenario.
What battery did you put in this thing? OEM or some garbage?

quattroluvr · Jul 26, 2023

OEM battery.
I'm going to get new charger asap.
Goign to try my pretty new booster pack

quattroluvr · Jul 26, 2023

@SaVAGeSoot @volkswagens-for-life
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 85A wall powered booster from a buddy soon. Other ideas?

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

SaVAGeSoot · Jul 26, 2023

quattroluvr said:
The new battery sure seems suspect.

If you want to diagnose, you can.

2014 TDI starter battery replacement - probably...

Well, I've had my '14 since '18, and although it's never not started for me, I did notice it cranking slowly during our winters up here, have had a bunch of codes for low voltage events over the years, have had locks and aux heater codes, and other low voltage hints such as the EMS stepping in...

www.clubtouareg.com

SaVAGeSoot · Jul 26, 2023

Remove belt, repeat attempt and log.... You're almost there!

SaVAGeSoot · Jul 26, 2023

quattroluvr · Jul 27, 2023

@SaVAGeSoot @volkswagens-for-life

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?
The 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: added a column for rail pressure regulation in case that means something

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

rgh0 · Jul 27, 2023

Have you cracked open the HP rail connection to each of the injectors to see if fuel comes out when you crank showing that air has been purged from the HP common rail? If it takes a little time for fuel to come its probably air in the system that will be purged out by the process. If nothing comes out at all the issue may be with the HPFP not delivering any volume for some reason. You can check the pressure reulting valve by checking that no flow out the low pressure side when cranking as there should be non with the low pressure being measured.

Be very careful in this process as the high pressure if it develops can produce a jet that can cut severly

quattroluvr · Jul 27, 2023

rgh0 said:
Have you cracked open the HP rail connection to each of the injectors to see if fuel comes out when you crank ...

good diagnostic idea. I'll try that tomorrow, carefully.
Also going to go get a fuel pressure measure kit to check the low pressure fuel pump pressure, at the supply hose of filter canister.

Brendanm · Jul 27, 2023

Your 2500hpa is 36psi, which is exactly what I get with vehicle not running. It's very strange that you don't get any variance whatsoever.

quattroluvr · Jul 27, 2023

someone else explained that the pressure sensor has a limit to how low it can measure, hence when pressure is below 2500 it still reports 2500 exactly.

SaVAGeSoot said:
Something is very wrong here....
Why is the filter canister low on fuel level if he's "primed" the system SO MANY TIMES?
OP, are you sure you are priming the system correctly? Please show screen shot of how you are doing this!

1. When others open their filter canister, is the fuel level exactly at the top, or 1 inch below the top? A mech friend suggested I get a pressure measuring kit at an auto parts store and measure the supply line into the fuel canister, which I'll do today - maybe the low pressure fuel pump is underperforming.

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 gurgling 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 voltage regulator electronics module that's constraining the battery/starter-boost. Whatever that electrical root cause is, is likely the culprit.

SaVAGeSoot · Jul 27, 2023

Something is very wrong here....
Why is the filter canister low on fuel level if he's "primed" the system SO MANY TIMES?
OP, are you sure you are priming the system correctly? Please show screen shot of how you are doing this!

Dannyboy485 · Jul 27, 2023

In 20 years of dealing with common rail I have never once had to crack open anything to bleed. You are never supposed to open them at all other than a component failure. No mechanic anywhere will tell you to crack open a common rail to bleed it.
You can do it on the old inline or rotary pumps that operate at a maximum of 200 bar.
Common rails work on much higher pressure , they bleed themselves.

My advise is to verify the LP side first, if the hpfp isn't getting enough fuel your constantly running the hpfp dry and that leads to damage.

SaVAGeSoot · Jul 27, 2023

Dannyboy485 said:
My advise is to verify the LP side first, if the hpfp isn't getting enough fuel your constantly running the hpfp dry and that leads to damage.

I agree, but I'm also thinking that he's already damaged the new pump by now since he hasn't yet been able to get fuel into it.
I'm almost suspecting that he swapped the feed\return on the new pump after reinstalling it, or the new pump is a dud, or who knows..... it shouldn't be this hard to start the engine, but since he's replaced\deleted\changed SO MANY THINGS at the same time, it's nearly impossible to know without testing every single component individually......

If this was my engine, I wouldn't crank it over again until everything that was touched was double checked, and until the fuel pressure & flow was confirmed...... but I also don't just brick my running engine by replacing components that show no signs of failure as a preventative step to avoid failures I've read about on the internet.

rgh0 · Jul 27, 2023

If he repaced the HPFP he has already opened the HP common rails and got air into them. Tell me what the VW procedure is when you do this ???

SaVAGeSoot · Jul 27, 2023

quattroluvr said:
new Fuel Pressure regulator

This!
If the N276 fails, the engine will not run! It's a normally open valve! (so pressure is just dumped into return instead of built in rail)

quattroluvr · Jul 27, 2023

That's the first thing I replaced after having this no-start problem. New regulator AND then a new pressure sensor which are mounted on the rails.

rgh0 · Jul 27, 2023

If its normally open andrequires energisation to close off why does the injector rail pressure only slowly decay when the engine is turned off or am I wrong on this?

Dannyboy485 · Jul 27, 2023

Yes it does

SaVAGeSoot · Jul 27, 2023

So you select to run the test for 3 min but it runs for 1 min?
And... as long as you're hearing gurgling..... doesn't that indicate there's still air in the system?
Check output tests to see if there's anything related to the N276 to check if it's being commanded to do anything.

quattroluvr · Jul 27, 2023

SaVAGeSoot said:
@volkswagens-for-life
So you select to run the test for 3 min but it runs for 1 min?
And... as long as you're hearing gurgling..... doesn't that indicate there's still air in the system?
Check output tests to see if there's anything related to the N276 to check if it's being commanded to do anything.

I haven't timed the priming cycle exactly but it doesn't run for the whole 3 minutes maybe 1.5 minutes, which does seem odd, the fuel level is slightly below 1/4 tank so I should go get more fuel maybe the pump is heating up and thus not doing the whole 3 minutes.
Gurgling is problably too strong a sound-word, more like whining-ish/smoother sounding sounds during priming cycle.

WHOA! I just looked up "N276" regulator in the manual and I missed a step! I have both a new HPFP and a new N276 regulator...
"After the high-pressure pump and/or fuel pressure regulating valve -N276- is renewed, adaptation is necessary ⇒ Vehicle diagnostic
tester" <<< now I need to search around to where that adaptation lives in the vast menus of the VCDS. Will do that asap. Though the low voltage/low crank RPM problem seems quite independent of 'adaptation" so even after i do the adaptation, that problem will still be around.

Thanks to all for hanging in there and helping, really appreciate all the help.

low fuel pressure after HPFP replacement?!? advice?

2014 TDI starter battery replacement - probably...

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