Cold start problem

[Robert Hallyburton]

HI all,

I have a 2016 T6 Shutlle 150PS DSG. For the last few months I've been having a problem starting after leaving the vehicle overnight, roughly about 12 hours. I does start eventually but takes around 4/5 turns of the key to take life. Warm starts are fine and it drives as normal. I've replaced all the battery, glow plugs, including the expensive one, fuel filter, ran a full tank of BP ultimate Diesel, then a full tank with Diesel injector cleaner in it. Local garage think the injectors is the next thing to check. It's on 256k miles so cant complain if I have to replace them but wondering if we're on the right track?

PS VCDS shows no fault codes

Thanks

 

[Dellmassive]

we thinking low rail pressure?

or delayed increase in rail pressure. . . ?


if you have access to VCDS,. . .

see here and get a rail pressure plot.

Start up fault

Hi again, I'm trying to record my van when in fault with my new VCDS. I think the attached might show the fault? The problem is the fault doesn't present every start up. Once when I was trying to record it the VCDS just displayed n/a in every column. I've ticked the boxes that delmassive...

www.t6forum.com

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@mmi data plots below.

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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





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example of similar problem:

 

[Robert Hallyburton]

Thanks, for this, I've had a good read through and it could be the problem. Once i have it started, i turn it off and wait a couple of minutes and starts again and again from there with no problem so its just the initial start thats the issue, so does sound like a full pressure related problem thats resolved straight away once started.

Interestingly today the AAT on the dash showed 32 degrees when my wifes VW showed 19 degrees, a quick plug in with my handheld scan tool showed AAT as 32 as well, would this being out by 10/12 degrees affect it starting correctly?