VW Passat B6 Bluemotion 1.6 TDI 2010 - Starting Issue

**naza911** · 20-12-2018,07:03 PM

First post and all...so greetings

I picked up a B6 Passat not long ago, maybe 3 months ago, 60k miles from an old chap who used to use it for his fishing and trips out and about. Had a clean MOT history and full service history. Few bumps here and there but nothing I cared about. Earlier this week did a little round trip of around 200 miles ran like a dream, parked it overnight, next morning would not start properly.

The engine turns over starts; idles really bad, revs up and down then stalls. I added a bit more diesel as more normal mechanic was pretty much winding down for Christmas and was not able to take a look. He suggest it could be a fuel issue. Improved the situation a little however same sort of thing, car starts, idles smoother for a bit longer, as soon you press the accelerator, car stalls.

So far tried to following:

Scan for codes on generic OBD2 scanner, no codes at all. Shows fuel pressure 150kpa and 0% EGR Duty.
Running on pretty much clean oil, changed about 3 weeks ago
Replaced the fuel filter again just in case
No smoke from injectors but at stall it does let of some smoke from between exhaust and turbo link
Fuel pump is priming from the sounds of it, did a cycle of 3 primes then start but no luck

Its not been tested on the proper VCDS software for VAG's but not sure what else to try. Ran a few mechanics but all guessing. Is there anything else worth trying?

Also an recommendations for good VW garages around B'ham? tried Central VW but they are closed for Christmas, there are a lot of cowboys in B'ham so any recommendations for someone that will properly troubleshoot rather than take guess's would be great.

**philipharmes** · 21-12-2018,12:53 PM

Without any codes you won't want to be throwing any money at it.

If fuel pressure is only 150kpa, that's not nearly enough.

For free I would check you have a good flow of fuel going into the High Pressure pump.
I don't know about the 1.6 engine, but on the 2l there is an in-tank low pressure pump & a roller cell medium pressure pump between the fuel filter & the engine driven HPP.
On the 2l these only run while cranking the engine & when the engine is running, there is no prime cycle. ( These can be activated without the engine running via VDCS )

You could also look here for someone local with VCDS, although not the best weekend to look for help.
VCDS - Help Requests

Best of luck & let us know how you get on.

**Crasher** · 21-12-2018,09:43 PM

A CAYC engine, notorious for running issues, has it had the emissions recal done?

**naza911** · 22-12-2018,06:29 PM

So quick update on the issue. Had the RAC guy out, I was pretty sure he would have to tow it but he got it running. He put his computer on and got Low fuel pressure on the rail code: P00C600, consistent with with the pressure i reported first. The fuel pressure did increase on startup however a lot.

Anyway he continue with ripping up the back seat checking the fuel pump, gave it a few taps just in case the fuel picker was reporting wrong. To him the symptoms suggested fuel starvation. The fuel pump seemed good, tested it no issues. Scanned again, code still there. He opened up the fuel filter, fresh filter and plenty of fuel, no water/contamination. We did a few priming tests and fuel flow looked good.

He moved onto EGR even though no code for that, at this point he was puzzled as it what was wrong, in his experience the way the car would start and then stall did not make sense. Took of the lambda sensor to let some of the exhaust out so if it was DPF related then at least the car should idle, no luck. Consistent symptoms no new codes.

Next steps were removing the EGR pipe on the intake side and prevent EGR gasses coming back into the engine, start, spluttered once or twice however held its idle, after a few mins started to rev correctly as well. Let the engine warm up and seemed to be running good. What did he find, water droplets came out, very wet EGR pipe. Cleared the code, did a road test, codes were clear.

He took apart the some of the intake side to see if it was wet, it was all dry, filter + filter box all good. To take apart the Exhaust comps was too much work on the driveway so he left that but looks like water ingress on somewhere on the exhaust side is causing an issue.

Coolant looks good, no signs of leaking head, oil is about 3 weeks old, not cloudy. In terms of how the car is running, I took it out for a blast today has had a good 2-3 hour run. At Revs >1200RPM no issues however at lower revs especially if you have not given it gas the car feels like it wants to stall, get some surging in power. The gasket between the exhaust and the turbo is gone, that's where the fumes were coming from, not sure if the water has got in from there.

As there must have been water flowing through this engine, is it worth getting rid of the car, don't want to become a money pit. The exhaust gasket will be replaced see if that makes a difference. We still don't know where the water got in from in the first place, with covers on the underside and nothing in the intake, difficult to tell. As it starts now, I will get it down to my normal mechanic in the new year when he opens again, maybe when lifted maybe able to spot some cracks/holes.

**naza911** · 22-12-2018,06:32 PM

A CAYC engine, notorious for running issues, has it had the emissions recal done?

Not had the emissions recall, due to this issue and scanning the forums can see it causes more issues than it fixes. Did ring VW to confirm if the work had been done, they confirm it has not been.

**Rob69** · 22-12-2018,07:35 PM

So when the oil and filter were changed 3 weeks did the fuel filter get changed at the same time and then you've changed it again since then? I've heard that the fuel system on these common rails should be thoroughly primed to avoid damaging the HP pump after a filter change, I'm thinking maybe the first filter change initiated some pump damage and the 200 mile drive followed by a cold start the next day compounded it.

**naza911** · 22-12-2018,07:59 PM

Originally Posted by Rob69

So when the oil and filter were changed 3 weeks did the fuel filter get changed at the same time and then you've changed it again since then? I've heard that the fuel system on these common rails should be thoroughly primed to avoid damaging the HP pump after a filter change, I'm thinking maybe the first filter change initiated some pump damage and the 200 mile drive followed by a cold start the next day compounded it.

The filter has been replaced twice, priming was pretty primitive, key in hear the fuel pump; take key out and repeat another 2 times. Could be an issue however doesn't explain why we found water in the EGR pipe and problems are only at low revs <1200RPM. As the EGR and Cooler are one unit on these engines wonder if the coolant is leaking in. Not noticed the car drink coolant and the water that we found although black looks more like fresh water rather than they dye'd and alcoholic type that coolant is.

**Rob69** · 23-12-2018,07:41 AM

Have you been losing any coolant and had to top it up since you got the car, or lost any coolant since your 200 mile trip when this trouble seemed to start?

**naza911** · 23-12-2018,12:58 PM

Originally Posted by Rob69

Have you been losing any coolant and had to top it up since you got the car, or lost any coolant since your 200 mile trip when this trouble seemed to start?

None that I have noticed, to coolant tank has been between its normal ranges, however I have not been actively looking at it. Now the car has been started I am monitoring that to see if the car is loosing coolant. Took a pic yesterday and been driving it around, looked this morning no noticeable difference and the car did start like a charm this morning.

**DMitch16** · 24-12-2018,12:52 AM

Originally Posted by naza911

None that I have noticed, to coolant tank has been between its normal ranges, however I have not been actively looking at it. Now the car has been started I am monitoring that to see if the car is loosing coolant. Took a pic yesterday and been driving it around, looked this morning no noticeable difference and the car did start like a charm this morning.

Look inside the coolant expansion tank for a correct level - a great deal of them get stained within a few years if the coolant mixture is strong. My old tank had a permanent max level stained on the inside so I replaced it.