2015 Passat takes longer to start when it is colder

[Fixmy59bug]

This is a first for me....

None of my previous TDI's ever had this problem, including my 2013 & 2014 Passat's. Maybe it is something different about the 2015?

So when it starts getting colder (say below 35*F) it cranks a little longer before it finally starts.

This morning it was 31* (the coldest we've seen so far) and it took about 5 seconds of cranking before it finally started. In normal temperatures, it will start within 1 second of turning the key.

I havent changed anything from what I normally do. I turn on the ignition, wait for the instrument needles to do their sweep, then turn the key to Start. So there is plenty of time for the glow plugs to do their thing (even though in my climate they dont really do much).

I do add 9 ounces of Opti-Lube XPD everytime I fill the tank. So (theoretically) the fuel shouldnt be gelling. According to Opti-Lube, their Anti-gel protection threshold is -10*.

There are no codes stored in the ECU either. So as far as the car knows, it is operating correctly.

Am I being too critical or is this a sign of something looming?

 

[LeeM]

I've found that my 2015 has at times taken longer to start than the 2013 i had. I now wait for the airbag light to go out before cranking and it behaves better.

 

[bizzle]

I know it's a foreign concept to those of us out in the desert, but are you *sure* the glow plugs are fully warmed before you're cranking? Them not doing much in our climate is only true when it's not 30 degrees outside And as you've noted, this winter is freakishly cold.

I have keyless ignition on my 2015 so I can't possibly start the car too early (as far as I know), but now you're reminding me I need to text my wife since she's been taking the bug to work...

 

[turbobrick240]

There's another thread around here called: 2015 golf tdi long first crank, where a similar problem was caused by a defect in the variable valve timing oil control valve/housing. Those parts have been revised due to the issue. Here's a youtube link dealing with the VVT problem:
https://youtu.be/DXvHdmq0reA

 

[740GLE]

I'd def check for the GP light is out. Even in our 45 degree garage with kessy, it takes 3-5 seconds after pressing the button before the GP are out and it cranks over.

 

[turbobrick240]

I don't think the light going out correlates with the glow plugs shutting off. I know on my truck the plugs will glow for up to a minute or two after it starts (and the light is out) in cold weather.

 

[bizzle]

That's because modern diesels use (or at least can use) glow plugs for various emission controlling features--they aren't just for starting. That's a separate issue from the dash indicator going out to signal the engine is ready to start.

The light going out indicates when the engine is ready to start. Unless I'm misunderstanding your post, I don't understand why you're pointing out the glow plugs may not be turning off when the dash light goes out.

Or, put another way, regardless of whether the glow plugs are still operating after the dash light goes out, the vehicle can't be started until the glow plug light goes out.

If he's just hopping in his car first thing in the morning and turning the key without paying attention to the dash light, it's not going to start right away. The chances of someone doing that in the desert are extremely high, in my opinion, since I live in the desert, too. All over Southern California our TDIs normally start in about 1 second pretty much year round (even my '98) but this month is cold. I suspect it will take some effort to deprogram the muscle memory that develops from instant starting year after year all year round.

 

[turbobrick240]

Well, the OP said he isn't just immediately turning the key from on to start. Doesn't seem all that likely that it would be a glow plug issue on a fairly new car. Unless rodents have been working on the glow plug harness, which should throw codes. I'd wager it's either a fuel delivery or VVT oil control valve issue. I never had to wait more than a second or two in my mk6. If they don't winterize the fuel very well in that area, that could be the culprit.

 

[bizzle]

We're not saying anything is wrong with his glow plugs.

We're trying to explain that a car taking 1 second to turn over in normal temperatures but taking 5 seconds in 31F weather is normal behavior. Nothing is wrong in that scenario as described.

If the glow plug light is going out and then it's taking 5 seconds to turn over, something needs to be addressed.

The OP is speculating that something different from his past experiences is because the car is newer. I'm pointing out that in reality the new variable is the 30 degree weather our southwestern deserts are experiencing (this is even mentioned in the opening post, but the significance of this being the coldest it's ever been isn't being connected to the long start for whatever reasons).

Read the starting procedure again, please. It's very clearly stated that the OP puts the key in (so we know it's not KESSY and can be prematurely cranked), waits for the gauge sweep, and then cranks the car. That same paragraph explicitly states that the OP doesn't think the glow plugs are doing much in Nevada so that indicates the person isn't paying attention to the dash light. The person assumes the glow plugs are ready, but all of us who are currently in 40 degree or less weather right now are pointing out it takes at least a few seconds for the glow plugs to light off--certainly longer than a gauge sweep interval.

 

[bizzle]

I never had to wait more than a second or two in my mk6. If they don't winterize the fuel very well in that area, that could be the culprit.

Let's be very clear here, because you listed a long list of potential rabbit holes but I don't think any of us wants the OP going down a bunch of rabbit holes before resolving the simplest explanation first.

I wrote in my response that 5 seconds is normal in these weather conditions. 740GLE said the same thing. We're talking about from key off to engine starting. It takes a few seconds for the glow plugs to warm up enough to do their job and then a second or two to crank the car.

You write here that you have never had to wait more than a second or two, but you don't clarify whether you are talking about from key off to engine running or if you're talking about a 2 second crank (or 2 seconds before your glow plugs are ready). Since you're in Maine, I interpret your statement to mean that, once your car is ready to start, it only takes a second or two for the engine to turn over. Am I correct in that conclusion?

I don't know Maine weather that well. Do you use heaters in your garage to get the car ready in the morning? There might be a lot of little things you do that you don't even recognize simply because you live on the east coast. I doubt that you leave your house, hop in your car, and start it from dead cold to running in 1 to 2 seconds in January in Maine, but I also don't think that's what you meant.

Also, fuel isn't winterized locally like you seem to think based on what you wrote. Nevada doesn't have its own special fuel.

 

[turbobrick240]

I didn't have time to read those novellas, but 5 seconds of cranking is most definitely NOT normal. Trust me, I live somewhere where it actually gets cold, and never had to crank anywhere near that long.

 

[bizzle]

No one is saying 5 seconds of cranking is normal

You haven't given a single reason to trust your poor advice. You aren't even bothering to read the responses and instead insult the members trying to help in the thread.

 

[turbobrick240]

Settle down big fella . Nobody is attacking you.

 

[bizzle]

Posting snide comments about my contributions to this thread are personal attacks.

You probably think you're being clever but you're just being rude.

The worst part of all this isn't even the crap you're posting toward me, it's the incorrect information you keep posting that has the potential to freak someone out and seek unnecessary diagnoses and repairs.


EDIT: Fixmy59bug, I didn't start this thread with the intention of getting dragged into a pissing match with someone. If you'd like to do some more trouble shooting feel free to PM me. I also have VCDS if it comes to that.

 

[turbobrick240]

I suggest the OP should watch the video I linked to earlier. Unlike us armchair analysts, that Dutch guy is a pro.

 

[Fixmy59bug]

If he's just hopping in his car first thing in the morning and turning the key without paying attention to the dash light, it's not going to start right away.

That same paragraph explicitly states that the OP doesn't think the glow plugs are doing much in Nevada so that indicates the person isn't paying attention to the dash light.

Dont worry guys, I am waiting for the glow plug light to go off. I come from a long line of diesel drivers. One of the first vehicles I learned how to drive on was a 1980's Chevrolet Silverado Cheyenne with the diesel V8. It had the glow plugs which took up to 30 seconds for the light to shut off.. I am very familiar with the practices of driving a diesel.

When I let the guages do their sweep, the glow plug light is out by the time they are done and back at zero.

I made a small video this morning (hoping it would have an extended crank so I could document it, but this morning it started fine). The glow plug is to the left of the battery light for reference.

https://www.youtube.com/watch?v=83egSE5drY0

Read the starting procedure again, please. It's very clearly stated that the OP puts the key in (so we know it's not KESSY and can be prematurely cranked), waits for the gauge sweep, and then cranks the car. The person assumes the glow plugs are ready, but all of us who are currently in 40 degree or less weather right now are pointing out it takes at least a few seconds for the glow plugs to light off--certainly longer than a gauge sweep interval.

If the glow plug light is going out and then it's taking 5 seconds to turn over, something needs to be addressed.

This IS the problem I am having. AFTER the glow plug light shuts off, when I turn the key. The starter begins cranking the engine, and after cranking for about 5 seconds, it then starts.

We're trying to explain that a car taking 1 second to turn over in normal temperatures but taking 5 seconds in 31F weather is normal behavior. Nothing is wrong in that scenario as described.

The video I posted above from this morning shows normal starting. If it did this every time, I would not have created this post. Unfortunately, that is not what it does. I will try to capture it on video, and when I do I will post it here.

I wrote in my response that 5 seconds is normal in these weather conditions. 740GLE said the same thing. We're talking about from key off to engine starting. It takes a few seconds for the glow plugs to warm up enough to do their job and then a second or two to crank the car.

But its not 5 seconds from key on to engine starting.

Key on -> Gauges sweep -> Glowplug light off -> turn key, engine begins cranking over -> .....................5 seconds of cranking............ -> engine starts.

I suggest the OP should watch the video I linked to earlier. Unlike us armchair analysts, that Dutch guy is a pro.

I did watch it, and it is VERY interesting. The extended cranking is what I am experiencing.

EDIT: Fixmy59bug, I didn't start this thread with the intention of getting dragged into a pissing match with someone. If you'd like to do some more trouble shooting feel free to PM me. I also have VCDS if it comes to that.

I thought I started the thread and you just replied to it... =^)

I also have VCDS, I just dont know what I should be looking for. I wonder if it is possible to log the same graph that the guy did in the video.

 

[bizzle]

Indeed! I meant to write that I didn't start participating in this thread for any other reason than to help out rather than argue with someone

It's ridiculously cold right now, but I ran outside to test the timing to start.
My thermostat says it's 34F outside but my car's dash showed 41F.
It took about two seconds for the gauges to finish their sweep. The GP lights were out by the time the sweep finished. It started immediately after that--maybe 1 second or 3 seconds total from sitting down to engine running.

I just went back to find that video. If you're talking about testing the fuel rail pressure, here is a video to do that with VCDS: https://www.youtube.com/watch?v=k50Z5JLfuJs

 

[goodmonkey]

Just curious, is the prolonged starting when it has dropped below freezing? An additional half second isn't a big deal, but going out to 5 seconds of cranking is. If only once things have reached freezing point, there could be water in the fuel filter.

Do you notice the engine speed slowing down any? That also could be a sign that the battery is weakening. In my experience, they like to die in cold weather. The only time when I've not had a TDI fire up pretty quick that isn't a major problem it is related to the battery weakening. Of course, the battery performs better when it warms up, which then there is less a draw from the glow plugs, the engine turns over faster, and it starts faster.

I can't recall our '15 taking any longer to start in the cold vs the other TDI's we've had, but we were less likely to have it out in the cold. That is about all I can offer. Good luck.

 

[Fixmy59bug]

Just curious, is the prolonged starting when it has dropped below freezing? An additional half second isn't a big deal, but going out to 5 seconds of cranking is. If only once things have reached freezing point, there could be water in the fuel filter.
Do you notice the engine speed slowing down any? That also could be a sign that the battery is weakening. In my experience, they like to die in cold weather. The only time when I've not had a TDI fire up pretty quick that isn't a major problem it is related to the battery weakening. Of course, the battery performs better when it warms up, which then there is less a draw from the glow plugs, the engine turns over faster, and it starts faster.
I can't recall our '15 taking any longer to start in the cold vs the other TDI's we've had, but we were less likely to have it out in the cold. That is about as far as I can offer. Good luck.

No. extended cranking is not always below freezing. As a matter of fact, this morning and the day I created this post were the first two days it has gotten below freezing this winter. I dont think temperature is a major factor as I think it may have done it a time or two in the fall.

The engine cranking speed has not slowed down a bit. I do not believe the battery is going bad. Fortunately I work at a dealership (though, unfortunately no longer a vw dealership) so I can test my battery today before I go home.

 

[goodmonkey]

Sounds good. I just watched that VVT video turbobrick mentioned. Really nice approach on finding the problem.

 

[bizzle]

Not to put too fine a point on it, but why haven't you scanned the car for codes with VCDS? Or if you have, please post any codes or tell us it's all clear.

According to that video and subsequent comments, the VVT issue seems to present a code when it occurs (three of them comprise the title of the video).

The following comments in that video should be considered:
"B" wrote that his US 2015 has a completely different VVT setup that doesn't have the reservoir.

"Harry Kendal" described a similar issue (without any codes); it was a failed tandem pump.

"Robert" described a similar issue (always with P0341); it was the VVT but it's also worth mentioning that even with that code Dan cautioned him with, "Robert be carefull to just install new parts without a proper diagnosis! It doesn't need to be that your car has the same issue as the one in the video!" (sic)


I've never seen this problem on a TDI, but on the 2.0s we'd get cold start issues like you're describing due to faulty crankshaft position sensors. I don't know if it *only* happened with aftermarket sensors, but it *always* happened with them.

But again, we're all just unnecessarily spinning our gears here. Scan the car and let us know what the data are, please.

 

[tdiatlast]

How long does the car sit between the slow-start episodes?

Maybe the fuel rail is losing pressure after "x" hours? Isn't there a check valve to present this?

 

[Fixmy59bug]

Not to put too fine a point on it, but why haven't you scanned the car for codes with VCDS? Or if you have, please post any codes or tell us it's all clear.

Allow me to quote the second to last line in my original post.....

"There are no codes stored in the ECU either. So as far as the car knows, it is operating correctly."

I will scan again and see if there are any pending DTC's.

According to that video and subsequent comments, the VVT issue seems to present a code when it occurs (three of them comprise the title of the video).

The following comments in that video should be considered:
"B" wrote that his US 2015 has a completely different VVT setup that doesn't have the reservoir.

"Harry Kendal" described a similar issue (without any codes); it was a failed tandem pump.

"Robert" described a similar issue (always with P0341); it was the VVT but it's also worth mentioning that even with that code Dan cautioned him with, "Robert be carefull to just install new parts without a proper diagnosis! It doesn't need to be that your car has the same issue as the one in the video!" (sic)


I've never seen this problem on a TDI, but on the 2.0s we'd get cold start issues like you're describing due to faulty crankshaft position sensors. I don't know if it *only* happened with aftermarket sensors, but it *always* happened with them.

But again, we're all just unnecessarily spinning our gears here. Scan the car and let us know what the data are, please.

After watching the video, I googled the part numbers. After searching for the valve, on page two there was a link back to TDIClub where apparently this thread is in the Mk7 forum.

http://forums.tdiclub.com/showthread.php?t=481340

Where Kerma mentions the ECU could be purging air from the fuel system. I respect Kerma, They seem to know what the heck they are doing. But I have never heard of this being a possibility. Is there a way to verify this scenario?

 

[Fixmy59bug]

How long does the car sit between the slow-start episodes?

Maybe the fuel rail is losing pressure after "x" hours? Isn't there a check valve to present this?

Overnight. Always overnight, cold start in the morning.

I know there is a one way valve built into the top of the HPFP. And there are fuel return lines from the injectors.

But since its an intermittent failure I dont think this would be the case.

 

[tdiatlast]

What do you mean by "intermittent failure"? If it's happening "always overnight", why not check the one-way valve? Isn't it a (cheap) fix?

Maybe it's not ambient temp related at all...

 

[bizzle]

Allow me to quote the second to last line in my original post.....
"There are no codes stored in the ECU either. So as far as the car knows, it is operating correctly."
I will scan again and see if there are any pending DTC's.

Sorry, I missed that.

After watching the video, I googled the part numbers. After searching for the valve, on page two there was a link back to TDIClub where apparently this thread is in the Mk7 forum.
http://forums.tdiclub.com/showthread.php?t=481340
Where Kerma mentions the ECU could be purging air from the fuel system. I respect Kerma, They seem to know what the heck they are doing. But I have never heard of this being a possibility. Is there a way to verify this scenario?

Those part numbers have been superseded (at least on the Golf discussed in that thread). If you're talking about Kerma's post describing a programmed routine intended to address premature HPFP failures, are you asking how to verify whether that's correct information or how to verify if your vehicle is doing that?

A bunch of people in that thread exhibiting various symptoms that look like yours (except at least one person said his only has issues in warm temperature but cold is fine) but none of them have found a fix based on the actual VTT from what I read.

One person said he replaced his lifter pump (and said it won't throw a code so VW wouldn't address it under warranty for him, which also means you could have that issue and not know it). If the lifter pump is the same as the tandem pump mentioned in Dan's video, then that's two people who had the same symptoms as yours and fixed it with that pump. He speculated it could be they were sitting for so long with fuel in them. It's also mentioned in post #78 as a fix for that person.

The last post of that thread points back to the battery. That person claimed batteries run great until they don't and by that I mean one day the battery will just be dead even though it was working perfectly fine a short time before. My '98 and '12 were like that: batteries were perfectly fine one day and then completely unsalvageable the next. My bug has needed a new battery replacement for both of the past two years. Luckily, I have Interstate so they're always within warranty but they don't last a year.

Post #74 claims his 2011 is exhibiting the same issue

 

[Fixmy59bug]

What do you mean by "intermittent failure"? If it's happening "always overnight", why not check the one-way valve? Isn't it a (cheap) fix?

Maybe it's not ambient temp related at all...

Sorry, I meant to say SINCE it is an intermittent failure.

It is an intermittent problem since it does not happen every time. BUT everytime it happens it has always been parked overnight.

I would think if the check valve in the HPFP, it would throw some code. I suppose the only way to know is to do a leak down test on the fuel rail.

 

[740GLE]

HPFP valve is a metering valve, isn't there a rail pressure control valve at the end of the rail that is supposed to maintain pressure needed for by the ECU?

Seeing there are so many sensors on the high side in the rail, a code has to be thrown, same with failing GP.

I think VVT issue pointed out is the right direction to look.

One thing to try is double plugging the car, its a cheap try, see if it has any change on it.

 

[Fixmy59bug]

I just checked the SSP and you are correct, there is a pressure regulator valve on the end of the fuel rail. However, as you said I would suspect it would throw a code if it failed.

I checked yesterday and I do have the old style VVT on my head. I wonder if there is a way to test/clean it?

And what do you mean "double plugging the car"?

 

[bizzle]

I checked yesterday and I do have the old style VVT on my head. I wonder if there is a way to test/clean it?

Reproduce the test in the DiagnoseDan video (and I just watched it again and that specific car he's working on doesn't have any codes, either). I linked a video explaining how to check fuel pressure in VCDS. If that video doesn't show how to do a graph, google how to create graphs in VCDS. If you bought it from Ross-Tech directly I think you can just call them up for advice, but I'm not sure on how long after purchase they give you assistance like that.