T6.1 hot start issue.

[Jackmarkley24]

Hi guys, i have recently bought a 2021 110ps 5 speed, i have a problem where when the van is hot, very occasionally it tries to start, sounds horrible for a second and stops, after about 4 turns it will start. I had my mechanic look at it but nothing can be found obviously. It only happens every so often like once in every 4-6 weeks. I had a 2009 golf that done the same so maybe a common problem ? Anyone had the same and sorted it ? Thank you

 

[whodat]

'Sounds horrible'

What like me singing in the shower?
Bit more detail Jack.

 

[Jackmarkley24]

Haha sorry for the description

It sounds like its running really rough or not on all cylinders. I don’t get any warning lights etc. its bad enough to think WTF was that and quickly turn it off.

 

[whodat]

Nice one.
Have you done a diagnostic?
VCDS (with someone who can understand the output) or OBD or Carista?

 

[Jackmarkley24]

Yes diagnostics been done and nothing found

 

[whodat]

Intermittents are the worse problems to diagnose.

Does it really only happen every few weeks? Could it be that it happens if you stopped a regen, for example, or if you had a long fast drive and turned off the ignition without a chilling out period, or something that forms some sort of pattern (- as in , you lost your keys, where did you last put them - stupid questions but have to be asked)

 

[Jackmarkley24]

It has happened about 4 times in 6 months, when a regen starts i always drive the van hard to finsh the regen process, this is also a pain there seems to be no pattern at all but it is only when hot. Thanks for your thinking !

 

[whodat]

Every 6 weeks is a little hard to pin something down.
If you have a Carista or OBD or VCDS - next time it does it, plug it straight in and do a diagnostic before restarting it (so it doesn't have a chance to wipe any fault code)

Just for your info - and each van might be a little different - having connected a Carista during a regen - mine doesn't matter if I'm stuck at traffic lights or at 3000rpm - the soot still goes down at a constant rate during a regen (on my T6.1) and it does tend to start a regen 1 min from home or every 200-220 miles or so.

Let us know what you come up with - even if it is nothing. Hope someone else can come up with more educated guess.