T6 Wouldn't Start

[Tourershine]

Thanks @Dellmassive

I go on holiday at the end of the week, but my van will be with VW having the paintwork done.
I will mention to them if they get it done in the first few days, to just park it up and not touch it. That way they can re-start it in a week or so, with a tech stood there, to see what happens. This might work, it might not, but i'm off on a longer holiday in August, and this is the sort of downtime the van hates, so I will do the same as you and record it starting.

Hope you enjoyed the holiday, and now you're home, there's no excuse to pop up for breakfast

 

[Dilbert]

I will mention to them if they get it done in the first few days, to just park it up and not touch it.

Hi @Tourershine , did you get to the bottom of this problem? Mine has done it again today - exactly as you described. Happened twice now and always after leaving for a 2 or 3 weeks but it doesn't happen every time it is left for long periods.

Thanks!

 

[Tourershine]

Hi @Tourershine , did you get to the bottom of this problem? Mine has done it again today - exactly as you described. Happened twice now and always after leaving for a 2 or 3 weeks but it doesn't happen every time it is left for long periods.

Thanks!

I haven't had the van laid up for a long period of time since. My last holiday the van was still in use with my colleague. I will be interested if you get it fixed though. My suggestion is next time you leave it for a long period, set up your phone recording you starting the van, so you can see and hear what it sounds like for VW to look at.

 

[Dilbert]

set up your phone recording you starting the van

That is what I was thinking of doing .

I am sure it happened at a similar time of year last time and I am wondering if it is related to change in temperature whilst its stationary (mild to cold weather) which is causing a pressure change in the fuel/injector system. Obviously not the root cause but may be exaggerating the issue.

 

[Dubhgall]

sounds like low fuel rail pressure and airlock . . . ?

possibly the fuel in the rail has bled down and the priming pump and HPFP is trying to building up rail pressure . . . . . . possibly purging any air out the system, on that first re-start.

must admit not had this myself before . . . . . normally just a flat battery after a couple of weeks.

might be worth mentioning to the dealers as they may have seen similar for other vans sitting around on the lot for ages or new vans being delivered that haven't been run for a long time.

***********

Key in, ignition on for couple of seconds, and it fires up, but runs really rough on 3 cylinders. - (remaining fuel in rail + HPFP)
Turn off, start again, and the same. - (remaining fuel in rail + HPFP - system starting to repressurise + purge)
Turn off, try to start and it's just spins over. - (rail + lines out of fuel + airlocked? awaiting fresh fuel for HPFP to fill rail)
Try few mins later and it starts, but still a little rough on tick over, so leave running for a few mins untouched and eventually it seems to clear. - (HPFP clearing air out of HP line and rail/injectors)

************

a possible check return valve faulty? allowing rail pressure to drop and bleed back down to tank causing an air lock and needing purging on restart?

There is a test they can do by monitoring the rail pressure:

Running pressure: as per spec
rest after run: pressure should increase due to heat soak, then drop and remain at rest.
rest over night / after 24hrs: bleeddown, pressure shouold remain to spec and not drop too much.

I've had a dig around, but couldn't find anything that was similar.

I've just got home after 2 weeks away in my Motorhome. The first thing I tend to do, is check all the vehicles that have been sat for a few weeks.
Low and behold the van wouldn't start. I had the exact same last time I went on holiday and left it sat for a longish period.

Key in, ignition on for couple of seconds, and it fires up, but runs really rough on 3 cylinders.
Turn off, start again, and the same.
Turn off, try to start and it's just spins over.
Try few mins later and it starts, but still a little rough on tick over, so leave running for a few mins untouched and eventually it seems to clear.

No smoke, no engine lights, no warnings.

I'd say it's because it's been sat, but really... ? It's a 2017 modern diesel, not an old banger.
It's due another service, but I know if I mention this to VW, they won't find anything, because there's nothing for them to find.

Any thoughts?

what was the final solution as I have same problem/

 

[Tourershine]

what was the final solution as I have same problem/

I never got to the bottom of the problem because it never did it again.

 

[Dubhgall]

I never got to the bottom of the problem because it never did it again.

Lucky you, I guess I will need toybook it into workshops but having read some horrendous diagnostics reports I was hoping some one may have come up with oh thats a common problem - replace the ********* valve and away you go, hey ho.
Thank you.

 

[Mud Digger]

Thanks mate. I knew when you popped up as on line, you'd be drawn straight to my issue Captain McSpanner

I will mention it to the tech and see if they can run a test.

before you try all that try that little thing called Patience lol.... let the glow plug light go out turn it off do it a 2nd time even a 3rd get the glow plugs glowing and it ll start on all 4 cylinders i betchya ....

 

[Dubhgall]

before you try all that try that little thing called Patience lol.... let the glow plug light go out turn it off do it a 2nd time even a 3rd get the glow plugs glowing and it ll start on all 4 cylinders i betchya ....

Good morning, tried glow plug on off last night after van had been switched off for best part of six hours and it started perfectly, as it had done several times during the course of the day.
Tried it again this morning after glow plus on off routine - back to same rocking and shaking on 2/3 cylinders only and for approx three minutes at 1500 rpm before it kicked in on all four and run smoothly. I suspect losing fuel pressure overnight and having to self purge air from the system over a two to three minute period and then its fine. question is what is not doing its job. The van runs great after its 'bled' itself!!!!!
Any further suggestion greatly appreciated.

Thanks

 

[Dellmassive]

possibly an injector allowing the fuel rail pressure to bleed down into the derv return line? - causing the rail to need re-priming and pressurising during the initial restart?

@Flyingspanner . . . any input on this?

 

[Grim Reaper]

Or a lift pump failure.
Suggest changing the fuel filter and opening the old one up to see if there's a load of black carbon in there from the lift pump brushes

 

[Flyingspanner]

Try running some cleaning fluid through the fuel system as a cheap test, if injectors are carboned up, could cause leakdown in cylinder.
Are you loosing coolant?
I will dig-out the part number later.

 

[Flyingspanner]

Also G247 I’m told is an issue.

 

[Dellmassive]

good info there. . .

id imagine you would get a error code with a G247 fault?


16575/P0191/000401 - Fuel Pressure Sensor (G247): Implausible Signal

Possible Symptoms

• Malfunction Indicator Light (MIL) ON

Possible Causes

• High/Low Fuel Pressure implausible
• Low Fuel Level or Fuel Tank empty
• Wiring and/or Connector(s) from/to Fuel Pressure Sensor (G247) faulty
• Fuel Pressure Sensor (G247) faulty

Possible Solutions

• Check Fuel Tank Level
• Check Fuel Pressure
• Check Wiring and/or Connector(s) from/to Fuel Pressure Sensor (G247)
• Check/Replace Fuel Pressure Sensor (G247)

Special Notes

• When found in VW Polo (9N) with 1.4l FSI (AXU), check TPI 2009218 which describes a problem with the Fuel Pump.
• When found with the Common Rail TDI engine, check for signs of HPFP failure (metal shavings).

16575/P0191/000401 - Ross-Tech Wiki

wiki.ross-tech.com

 

[Dubhgall]

Thanks for all the feed back people. My local garage referred me to a diesel specialist nearby and have booked van in for Monday to carry out testing. However, when we spoke on the phone he said its most likely a faulty injector as it is a common problem he experiences with VW, Audi and Skoda and was very familiar with symptoms as described.
So feeling confident of a favourable outcome and will post soon as known.

Thanks again.

 

[Flyingspanner]

@Dellmassive You would think so, but EGR and fuel pressure have caused issues of rough running or non/poor start with no codes logged, so not always.

I have heard of a tech bulletin to replace G247 if nothing else found (all of what you have already listed and rule out high contact resistance at the sensor like when the pin inside the plug no longer grips correctly, easy tested with a male repair wire and see if it is gripped nicely when sliding it into each of the three terminals).


I usually check what is actually going on with these puppies:

 

[Dellmassive]

Thanks for all the feed back people. My local garage referred me to a diesel specialist nearby and have booked van in for Monday to carry out testing. However, when we spoke on the phone he said its most likely a faulty injector as it is a common problem he experiences with VW, Audi and Skoda and was very familiar with symptoms as described.
So feeling confident of a favourable outcome and will post soon as known.

Thanks again.

keep us posted with as much info as you can.

 

[Dellmassive]

@Dellmassive You would think so, but EGR and fuel pressure have caused issues of rough running or non/poor start with no codes logged, so not always.

I have heard of a tech bulletin to replace G247 if nothing else found (all of what you have already listed and rule out high contact resistance at the sensor like when the pin inside the plug no longer grips correctly, easy tested with a male repair wire and see if it is gripped nicely when sliding it into each of the three terminals).


I usually check what is actually going on with these puppies:

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looks like you got a nice collection of toys to play with there =]



.

 

[Flyingspanner]

looks like you got a nice collection of toys to play with there =]



.

All the gear, NO IDEA

 

[Dubhgall]

keep us posted with as much info as you can.

Hi
collected van yesterday morning from diesel specialist mechanic and started perfectly however, he had already started it prior to my collecting it so, I held off from this reply until I checked it myself this morning.
Starting and running perfectly hurrah.
Injectors were removed, 'de-coked, de- gunged', re- calibrated and replaced.

Happy bunny