Cold hard start

[armstrongtrucks]

2015 Passat. First cold start of the day taking a lot of cranking. Once it starts the rest of the day it fires up normally. 97000 miles and all filters changed at 90,000. No sign of any diesel leaks as it sets in the garage.
Any suggestions?

thanks in advance

 

[bustNfuel]

I'm at 108k and mine's starting to have difficulty starting. Extended cranking for about 3-5 seconds, then stumbles and runs. Runs fine afterwards.

Then last week I had a CEL with two codes, and after further investigation found a lot of sludge in the bottom of the intercooler. I wonder if yours is about to have the same problem.

My post here, with pics:

P026A code and intercooler buildup

Well, I just cleaned my intercooler and instead of green goo I find plain old black oil, quite a bit of it. And, I am now getting a high pitched whooshing or whining sound at moderate to full boost, particularly at low rpms, sounds louder on the passenger side. I bet my turbo is on its last...

forums.tdiclub.com

 

[pedroYUL]

2015 Golf TDI long crank first start of the day

Hey Guys!! I'm new to the form but have had diesel VW's for about 6 years now. I am more familiar with the MK4 Jetta's but recently purchased a 2015 Golf TDI and I'm really liking it. Anyway as the title says I'm experiencing a longer than normal cranking period the very first start of the...

forums.tdiclub.com

Your 2015 Passat is closer to a 2015 Golf than anything else (quoted thread). I will save you the pain to read the many pages there, there are multiple factors to consider:

1. Battery. Make sure it is good, if still the originally fitted, then consider a new one.
2. Variable valve timing system: This is one of the first things considered in the thread. You can open the very end of the valve, make sure oil is nice and liquid there with no crud, no chunks in those passages.
3. Crank position sensor: Other threads have pointed to cars with flakey sensors and no codes set by the ECU at all. Changing the sensor is easy and cheap if you can DIY, just something to take out of the equation if you keep experiencing long cranks and perhaps some hesitation when driving.
4. Priming: Make absolutely sure your fuel system is well primed, the transfer pump (inside the tank) can be commanded to run by VCDS with both the engine off, and also running; try it both ways a few times. Also, some people (including me) have changed the pump for a new one, not crazy money if you DIY, but not peanuts.
5. Not discussed in the thread, but I would also recommend to have a quick look at the screen and inside the hole of where the pressure regulator lives on top of the HPFP. Just undo the two T20 screws and wiggle the regulator out. If there are metal flakes anywhere in there, you HPFP is seriously compromised, to the point of absolutely grounding the car until the pump is changed.

 

[Tom in PT]

I started that intercooler buildup thread in post 2 and FWIW I never had a hard to start situation arise, ever, in my '13, even with intercooler buildup.
In addition to pedroYUL's excellent suggestions, I would also mention make sure the glow plugs are cycling and give it a 5 seconds before you turn key to start to make sure they have done their business. If that does not change things, proceed along his suggestions. There must be NO air in the fuel system.