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?

 

[baltyre]

Hi
2017 t6 just started mine this morning and started fine but noticed the revs were not raised like normal IE choke. It is 22degrees out so just wondering if this was normal. No problem starting either.

 

[T6Camper17]

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?

Hi Robert. Did you ever get this sorted, and if so what was the solution?

I have a T6 2.0 150bhp and it has been hard to start in the cold ever since I got it 2 years ago. All the usual stuff changed out and starter rewound, which helped but hasn't fixed hard cold start.

Next things to try is new injectors, but I can't know for sure if even this will solve the problem. Thanks in advance.

 

[Robert Hallyburton]

Hi Robert. Did you ever get this sorted, and if so what was the solution?

I have a T6 2.0 150bhp and it has been hard to start in the cold ever since I got it 2 years ago. All the usual stuff changed out and starter rewound, which helped but hasn't fixed hard cold start.

Next things to try is new injectors, but I can't know for sure if even this will solve the problem. Thanks in advance.

Hi, the timing belt was out ever so slightly. “By a tooth” the mechanic said. So was ok when warm but engine didn’t like it when cold. Ran perfect ever since.

 

[T6Camper17]

Hi, the timing belt was out ever so slightly. “By a tooth” the mechanic said. So was ok when warm but engine didn’t like it when cold. Ran perfect ever since.

Thanks for the reply Robert. Belt was just done just before I got it, 40k kms ago. The compeny I bought it off had their own mechanics and did it themselves. So I might just get it done to see if that sorts it.

Van starts absolutely fine after the initial start, and the issue is essentially non existent in summer. Thanks again, Patrick.

 

[Robert Hallyburton]

Thanks for the reply Robert. Belt was just done just before I got it, 40k kms ago. The compeny I bought it off had their own mechanics and did it themselves. So I might just get it done to see if that sorts it.

Van starts absolutely fine after the initial start, and the issue is essentially non existent in summer. Thanks again, Patrick.

Just out of curiosity, does the start/stop work?

 

[T6Camper17]

Just out of curiosity, does the start/stop work?

It does, but it's very sporadic. Might work sometimes, might not other times. Sometimes when it does it might only cut the engine for seconds, other times it could stall engine for minutes. Always starts without issue when stop/start does work.

Did you have a similar issue? Might it point to the timing being out as the issue?

 

[Robert Hallyburton]

Mine just stopped working completely for about 18 months. I never related the two issues until the timing was sorted to spec and its worked fine ever since. Sounds like yours is working ok though.

 

[T6Camper17]

Mine certainly isn't right, compared to the stop/start on our A6 and Tiguan. If I was to put a % on it I'd say it works less than 50% of them time, and half of that time it stalls the engine for about 2 seconds. So there is certainly an issue. Maybe linked to timing!