Another intermittent starting issue

[BenWomersley]

Hello,
Have an intermittent starting issue on a 2019 T6. No error codes, nothing on the dash. When the issue happens it turns over continuously but doesn't start. After a few, sometimes 6 or 8 attempts it starts fine. Did this a few times a couple of weeks ago, just done 1600 miles to France and back absolutely fine, now it's doing it again.
Drives fine, no issues at all once the engine is running.
Battery is good, checked metering valve filter for 'glitter', replaced fuel filter (was only 18 months old). Runs when sprayed with easy start (then dies when you stop spraying).
I don't think I can hear the fuel pump running when it fails to start so wondering if fuel pump relay might be to blame? Imagine if it were the pump itself, issues with the high pressure fuel pump, timing etc there would be issues when the engine was running too.
If anyone can offer any advice, that would be amazing and much appreciated!

 

[Sasquatch]

Try the spare key for a few days. It's probably not that, but its an easy and free test so worth eliminating,

 

[BenWomersley]

Thanks, worth a try.

 

[Del94]

I had this fault on my 2018 T6 it was eventually found to be a relay on the fuel pump/system.
Was really difficult to find because it also never left a fault code.
The RAC breakdown person the attended when it first happened called it as a fuel pump issue but the VW main dealer dismissed him as “they knew better”.

 

[BenWomersley]

Thanks Del94, that's good to know. I will start with the fuel pump relay as that sounds to be the most obvious, then look at what other fuel related things have relays. Hopefully there aren't many!

 

[bobby69]

My van is at vw at the moment with this same issue it’s a intermittent fault but it did happen when vw assist had there computer connected technician told me there was low to nil fuel pressure as of Friday vw dealer has diagnosed it as a fuel sensor fault as they say it’s not throwing any faults but they have a technical bulletin on it
I’m awaiting approval for warranty work
I’ll keep you up dated if I mean when I get the van back
Van is a 2019 204 dsg 4motion roughly 50k miles

 

[bobby69]

I will call them Tuesday and tell them about the fuel pump relay might give them a nudge in the right direction

 

[Frigo110]

Hi,
I have the same problem.

Not 100% sure of the timeline but I think it started after my last service (Early August), fuel filter has been changed but i believe if it wasn´t primed proper it should be fine by now. Absolutely no problems while driving.

The van "only" did it 3 or 4 times in the last 5 weeks but I will start to investigate it now - I may sell it and don´t want anything wrong with it for the new owner.

 

[BenWomersley]

Hi,
I have the same problem.

Not 100% sure of the timeline but I think it started after my last service (Early August), fuel filter has been changed but i believe if it wasn´t primed proper it should be fine by now. Absolutely no problems while driving.

The van "only" did it 3 or 4 times in the last 5 weeks but I will start to investigate it now - I may sell it and don´t want anything wrong with it for the new owner.

That was my thinking, either air somewhere or clogging fuel filter. I only bought it a few months ago so wanted to personally change the filter to rule that out. Would imagine it would prime itself fully on the first startup after changing it.

I haven't had the issue reappear for the last 20 or 30 startups so it will be hard to know if its resolved or if it is still hiding.

Looks as though it is the same relay for the ad blue system on the same board under the battery so will try to swap them around this weekend.

 

[BenWomersley]

Yesterday morning it wouldn't start at all, I gave up after 20+ attempts.

Just swapped the fuel pump relay (number 8 in attached image) and the reducing agent metering relay (number 11) as they are identical and it started a few times in a row.

Hopefully not just coincidence, I order a replacement relay and bench test the hopefully broken one.

Only took 20 mins and is an easy process so thought I would share in case it's useful to anyone:

Remove battery partition, remove battery, remove some soundproofing, remove plastic cover plate under battery to reveal:

Fuel pump relay is circled.

 

[Frigo110]

Thanks for sharing.

I changed my battery and didn´t had the problem since.

 

[DJMowle]

my issue started off with this but now won’t start at all.

Did you manage to fix it?

 

[BenWomersley]

Yes, I fixed it with the relay change. Cost about £5 and took less than half an hour. Good luck