Start up fault

[Del94]

Really happy with the help so far - have never received any remotely useful input from the dealership.
But in there defence they never observed it faulting first hand only my videos.
VCDS has been fantastic so far - only my inexperience limiting it.

Reading the comments on the time stamps does this mean the lift pump isn’t activating in time or at all during this start up period? Talking about my van here, once I start the van cranking it never starts up in that period if in full fault.
The only time I’ve known it start in faulting mode was when the AA man was firing easy start in to the air intake.

 

[mmi]

Reading the comments on the time stamps does this mean the lift pump isn’t activating in time or at all during this start up period?

Just the opposite. The lift pumps is activated correctly - by turning ignition key to START - and it was active till end of the log.


However, it doesn't tell if the lift pump actually runs. I would expect to see a fault code for a faulty pump but unfortunately can't confirm if that's the case.

---

Of course you could try to test fuel lift pump with VCDS - just IGNition ON - engine not running.

Under Engine - Output tests you could run the pump (Fuel pump electronics) and just listen it's working (it's very distictive sound under left side of vehicle). If I remember correctly this test runs the pump for a few seconds, pauses, runs....




Under Basic Settings (under Engine) is a test for transfer fuel pump. Unfortunately I don't have any details about it (haven't even tried). Quite often on the screen there will be instructions what to do...



Anyways, I'm afraid there aren't many more "non-intrusive" ways to eliminate any other possible causes.

 

[Del94]

Just the opposite. The lift pump is activated correctly - by turning ignition key to START - and it was active till end of the log.
View attachment 147686

However, it doesn't tell if the lift pump actually runs. I would expect to see a fault code for a faulty pump but unfortunately can't confirm if that's the case.

---

Of course you could try to test fuel lift pump with VCDS.

Under Engine - Output tests you could run the pump (Fuel pump electronics) and just listen it's working (it's very distictive sound under left side of vehicle). If I remember correctly this test runs the pump for a few seconds, pauses, runs....

View attachment 147685


Under Basic Settings (under Engine) is a test for transfer fuel pump. Unfortunately I don't have any details about it (haven't even tried). Quite often on the screen there will be instructions what to do...

View attachment 147684

Anyways, I'm afraid there aren't many more "non-intrusive" ways to eliminate any other possible causes.

No problem, you’ve been amazingly helpful. I’m going to have to find a local decent technician I can get to undertake further investigation works that are beyond me recording data with the VCDS

 

[Dellmassive]

cracking bit of work @mmi

ill get another data set when i can to the van with VCDS.

still looking like low fuel rail pressure. . . no fuel. (AA Easy start is a giveaway)

we thinking issues with airlock in fuel lift pump link to filter.

leaking filter letting in air?

air in HPFP?

keep us posted.

 

[Dellmassive]

@mmi . . . finally managed to get to the van with VCDS.

see attached Block Maps.

static engine & tickover

 

[Dellmassive]

@mmi . . .

log file, IGN on --> startup --> tickover --> shutdown.

 

[Dellmassive]

@mmi

start-up rail pressure build.

@850rmp Rail pressure @ 27700kPa

 

[Del94]

@mmi

start-up rail pressure build.

@850rmp Rail pressure @ 27700kPa


View attachment 148598

Many thanks for your feedback. I’ve sent the info I captured to my van to a VW centre and they are taking it forward as it’s completely beyond me.
Luckily I’ve taken out the two year all in extended warranty so hopefully it’ll be resolved (vans booked in 30/03).
The information I got from this thread enabled me to use the VCDS which was invaluable.
Any further ideas please add them. Hopefully between the forum the VW centre and myself I can get it sorted after 3.5 quite annoying years

 

[Dellmassive]

@mmi

stop ---> run ---> stop

rail pressure log

 

[Dellmassive]

rail pressure build at start.

 

[Dellmassive]

rail pressure on 2500rmp limiter when in park/nutral.

89700kPa @ 2500rpm

 

[Dellmassive]

fuel rail pressure at shutdown . . .

was 29600kPa @ 820rpm tickover.

at shutdown rmp=0 rail pressure starts to drop.

by 20seconds later rail pressure dropped to half 1600kPa

by 30seconds later rail pressure dropped to min 800kPa

by 40seconds later rail pressure dropped to min 500kP

final resting rail pressure is 200kPa







@mmi so as you said the Rail pressure is not held for the next restart.


looks like rest its @ 200kPa,

key ON starts tank lift pump.

HPFP raises rail pressure to 30000kPa during cranking - (0.5 - 1.0 seconds)

once engine fires, 850rmp tickover and 2500kPa rail pressure.


@mmi Thanks for the help with getting the data and understanding it in a meaning full way.

 

[Dellmassive]

@mmi

i was looking for info on the CamBelt thing . . . and see this.

VAG SSP 514 – The New EA288 Diesel Engine Family - PDF for FREE

VAG SSP 514 – The New EA288 Diesel Engine Family designation EA288 new 4-cylinder diesel engines. Engine mechanics, Engine management system, EA288 engine with EU4 emission standard, Exhaust purification system for EU5 emission standard, Cylinder head, Thermal management

procarmanuals.com

im wondering if the N276 fuel rail pressure regulating valve is responsible for the drop in rail pressure after shut down?


do we know if this N276 is a parameter that we can LOG on VCDS to monitor its operation?


9 - G247 - fuel pressure sender
7 - N276 - fl prs reg valve
10 - pressure retention valve


.

 

[mmi]

im wondering if the N276 fuel rail pressure regulating valve is responsible for the drop in rail pressure after shut down?


do we know if this N276 is a parameter that we can LOG on VCDS to monitor its operation?

I believe the answer is: yes, yes.

Below a snippet of fuel related parameters from a "Record all" log. The downside by recording every single data channel is that sampling rate is about 1 sample/minute per each individual channel (top line - TIME). Thus the samples in each column here are not taken at same moment - they are quite a few seconds (tens of seconds actually) off from each other. E.g. the column 15:59:54 - engine was started within that recording thus some values (top) are engine off and some further down engine already running.

Anyways, the snippet just "proves" all these channels are live. Obviously need to make a couple of recordings by using just a few selected parameters
-

;SW:04L-906-056-KN	;Monday	20.12.2021​	15:58:46​	15:59:54​	16:01:01​	16:02:11​	16:03:17​	16:04:25​
			Engine OFF		Engine running
IDE00407	Rail pressure regulation: status		Control operation: ignition on	Control operation: ignition on	Regulated operation via quantity control valve	Regulated operation via quantity control valve	Regulated operation via quantity control valve	Regulated oper. via press. ctrl valve and quant. ctrl valve
IDE00589	Fuel pressure	kPa rel	0​	0​	31500​	30700​	74500​	48700​
IDE01378	Fuel high pressure: control deviation	bar	200​	200​	2​	-3​	26​	6​
IDE05632	Fuel pressure regulator valve actual value	mA	99.8​	384.3​	377.8​	371.3​	814.4​	944.7​
IDE05633	Valve for fuel metering: feedback value measured	mA	101.1​	99.9​	98.6​	99.3​	99.9​	806.1​
IDE07807	Fuel temperature sensor 1: B1: raw value	°C	7.2​	2​	9.5​	11.5​	22.2​	23​
IDE07808	Fuel temperature sensor 1: B1: before CR pump: raw voltage	V	3.714​	3.914​	3.626​	3.538​	3.049​	3.01​
IDE07818	Fuel high pressure sensor: actual value	bar	0​	316​	311​	319​	1100​	534​
IDE07819	Fuel high pressure sensor: unconditioned voltage	V	0.513​	1.133​	1.05​	1.104​	2.521​	1.49​
IDE07820	Fuel high pressure sensor: nominal value	bar	200​	320​	310​	317​	1094​	545​
IDE07821	Fuel metering valve: activation	%	9.29​	7.69​	7.34​	7.41​	7.32​	32.82​
IDE07822	Fuel pressure regulator valve: activation	%	7.4​	10.71​	9.86​	10.22​	16.75​	17.11​
IDE07824	Tank-internal presupply pump 1 bank 1: activation	%	0​	100​	100​	100​	100​	100​

 

[Thegee6]

I’ve just read through this with interest as have not such dissimilar issues. Mine is very intermittent and I can’t get the van to do it on demand, it’s very random. But when I put the hey in the ignition and come to start the van I get the flashing glowplug light. This typically happens areter it’s been driven and stopped after about 15 miles. But it has done it when stood. Then when I do start it I get “stop/start error” it also takes a few more cranks than normal to start. It has been into VW twice and the last time they couldn’t find a recorders fault so I got charged. Well the other day it played up I had Carista to hand and with the glowplug light flashing it pulled the fault code P0191 Fuel Pressure sensor “A” range/performance. It’s booked into VW again. The van only does this on start up and drives and run perfect otherwise and never faults when running.

Any thoughts??

 

[Del94]

The van has been in Camberley VW centre 3 times most recently.
First visit replaced fuel pressure sensor
Second cam belt and tensioner
Third (last week) replaced the crank sensor
After around 6 days the problem returned - I think it’s worse than ever
No good news from me unfortunately
I will probably now tidy the van up and trade it in - absolutely gutted as I love this van

 

[Del94]

Intermittent Start Up Fault - Resolved!

So, I’m just on my way back to the service centre to collect my van again! https://www.t6forum.com/threads/start-up-fault.33384/ After the centre replaced the crank sensor ( third visit, first visit fuel pressure sensor - second timing belt and tensioner ) the problem worsened dramatically...

www.t6forum.com

After the centre replaced the crank sensor (third visit, first visit fuel pressure sensor - second timing belt and tensioner) the problem worsened dramatically.

The van went back in on Friday and thankfully the technician managed to get the the computer on it and they witnessed the fault live for the first time.

Turns out they’ve found the fuel pump relay has a “dodgy pin” and was fitted that way when the van was built, hence the intermittent nature of the fault.

 

[Jeff@tuneserv]

Thank you have the vehicle back with me today. That might explain why the fault is recorded before it starts.
Cheers Jeff