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-   -   Strange regen anomaly- Have you experienced a really long regen? (http://forums.tdiclub.com/showthread.php?t=434166)

DerekG February 11th, 2015 16:35

Strange regen anomaly- Have you experienced a really long regen?
 
Just wanted to report an out of the ordinary experience simply for the sake of curiosity.

*First off the car ran perfectly the entire time. I didn't experience any loss in performance, strange noise, dash lights...etc. Just a really long regen.


On my way home from work the other day my car started a regen and I did like I always do and drove past my house and headed for the highway to let it finish. I have a scanguage II so I've always been able to notice regens right away and keep driving until they are complete, even if it makes me late for work or class lol

Every regen I've experienced up until this point has been 8-10 mins long regardless of whether it is city driving or highway driving. This time it lasted 25+ minutes and ~19 miles of driving in mixed city/highway. The scangauge read 1100-1400F Pre-turbo EGT and 1100-1200F DPF for the entire regen which in my experience is perfectly normal.

After 20 minutes I was starting to get concerned just because it has never had regen last that long. I disconnected the scangauge and then re-connnected just to see if it was a glitch, but it was still reading regen temps. What was also interesting was that while idling for a few minutes the aux fan didn't come on like it would normally do during a regen while sitting in traffic. Also note that the aux fan did come on during the first 10 mins or so of this regen like normal.

At about the 30 min mark I decided to turn off the car for a few seconds and then restart it just to see if this "soft reset" would help. After that the temps went back to normal and I went home.


My initial thought is that there was possibly a glitch in the scangauge that was making it read high even when the regen was over. That might explain why the aux fan wasn't coming on 25 minutes into the "regen".

Just looking for thoughts from you guys and if anyone else has experienced a similar thing. It hasn't had another regen yet since that was only ~70 miles ago, but I'll be sure and report back if the next one does the same thing.

Thanks!

VeeDubTDI February 11th, 2015 18:53

It isn't a glitch in the ScanGauge. I've had a long regen, but that was steady-state cruising on the highway. When I canceled cruise control, the regen stopped.

psrumors February 11th, 2015 19:03

i had a 25 minute regen at about 7k miles

DerekG February 11th, 2015 19:20

Alright cool, I won't worry about it then. I'm at 26,7xx miles now and the car is fantastic.

Cogen Man February 11th, 2015 19:51

Had one long regen in my 2011 Golf. Lasted about 25 minutes. If you noticed your coolant temp on your SGII was also up during the regen that's a good verification that the SGII is working fine.

DerekG February 11th, 2015 21:39

yeah, it was running 200-204 the whole regen. Usually runs 191-198.

hotpocketdeath February 12th, 2015 08:14

I just had a long regen the other day. Ended up driving around another 10+ miles to make sure it finished and I could park the car.

Kenn JSW February 13th, 2015 10:03

Quote:

Originally Posted by DerekG (Post 4735552)
On my way home from work the other day my car started a regen and I did like I always do and drove past my house and headed for the highway to let it finish.

I think a lot of us have done basically this, myself included. My thought on this is that it's very anti-economy, anti-TDI, anti-green, or whatever you'd like to call it. Also a necessary (?) waste of time. The economics of a TDI in most places are already questionable due to the large difference in the price of diesel vs. gasoline. (Almost a dollar per gallon more for diesel where I live). Doing this makes it worse.

So we burn extra fuel just driving around to let the car finish its regen thing. (And the car is already burning extra fuel during a regen). Part of the problem, at least in my case, is that the car seems to pick the absolute dumbest times possible to start a regen. I drive for a hour, and then one mile from my destination the regen starts. Every time! It sure would be nice to have some interaction with the computer. "Would this be a good time to start a regen?" Yes/No. Then it could be put off for a bit until it made sense. (If delated too much, one would be forced). Some owners could handle that (like most on this forum), and others couldn't deal with it, of course, so it would need to be an enabled feature. Won't happen of course, but it's what I'd like to see.

schultp February 13th, 2015 14:42

On this site it has become a standard for many that they must continue to drive until a regen is complete. In reality, I have never seen any data posted here, or elsewhere showing that this is a required behavior.

For me, on occasion I interrupt a regen when I arrive at home or work and I don't think twice about it.

Drive more, worry less.

Paul.

hotpocketdeath February 13th, 2015 16:39

Quote:

Originally Posted by schultp (Post 4737016)
On this site it has become a standard for many that they must continue to drive until a regen is complete. In reality, I have never seen any data posted here, or elsewhere showing that this is a required behavior.

For me, on occasion I interrupt a regen when I arrive at home or work and I don't think twice about it.

Drive more, worry less.

Paul.

IMO, this is more common sense. If you are aware that oil can cook in your turbo, why on earth would you ignore it and continue on as if it couldn't happen?

Look up what Turbo Coking is and you will see that the number one way to prevent it is to let the turbo cool down before shutting off the engine. This is a very real condition and can cause turbo failure.

meerschm February 13th, 2015 16:52

Keep in mind that the increase in temperature of the DPF is not because the exhaust is hotter, it is because the exhaust has extra fuel injected late in the cycle, which is then oxidized in the converter just prior to the DPF.

the fan that runs allows air to pass around the Converter/dpf to carry off some of this heat.

650 c is kind of warm.

hotpocketdeath February 13th, 2015 17:07

Quote:

Originally Posted by meerschm (Post 4737087)
Keep in mind that the increase in temperature of the DPF is not because the exhaust is hotter, it is because the exhaust has extra fuel injected late in the cycle, which is then oxidized in the converter just prior to the DPF.

the fan that runs allows air to pass around the Converter/dpf to carry off some of this heat.

650 c is kind of warm.

Actually, the exhaust pre-turbo is much hotter during regen. I keep an eye on exhaust temps 1 and 3. 1 is the temps before turbo and 3 is pretty much the DPF itself. During regen, it's normal to see the exhaust temps before the turbo stay much higher than during typical driving.

Personal preference, I like to make sure the exhaust temps are below 600F before shutting down the engine.

DerekG February 13th, 2015 17:42

I too would like to see some kind of regen "countdown" meter so I can plan accordingly. Also I don't see driving until it's finished as wasteful at all, apart from wasting 10 mins. It's going to do the regen eventually and I'm definitely NOT going to turn off the engine when the Pre-turbo EGT's are 1200+ degrees fahrenheit.

I usually let both 1 and 3 EGT temps go down under 475-500 before shutting off the car.

It's just part of owning a newer TDI. Yes it's inconvenient at times, but it's not something that would make me want to get rid of the car.

For me, fuel economy was secondary when buying the car. For years I loved the idea of a Golf TDI and how versatile it was. The ability to tow, build quality, handling, subtle styling, and the pure utility is what made me like the car. Good fuel econ was a great bonus.

I'm not someone that even thinks about the price of fuel, it's going to cost what it costs and there isn't anything we can do about it so it's pointless to stress about the few cents that separate the cost a gas vs diesel.

I bought a diesel golf because I wanted a diesel golf lol

VeeDubTDI February 13th, 2015 17:48

Quote:

Originally Posted by schultp (Post 4737016)
On this site it has become a standard for many that they must continue to drive until a regen is complete. In reality, I have never seen any data posted here, or elsewhere showing that this is a required behavior.

For me, on occasion I interrupt a regen when I arrive at home or work and I don't think twice about it.

Drive more, worry less.

Paul.

This has been discussed extensively. There is no scientific data to back up one method over the other because nobody has bothered to sit down with a sample of vehicles and interrupted regens for 100,000 miles and compared failure data to vehicles that have not had regens interrupted for 100,000 miles.

Common knowledge of oil coking temperatures and general mechanical sympathy would say that it is not good to turn off a turbocharged engine when the turbocharger is 1300F. It is the equivalent of pulling a heavy load up a mountain and turning off the engine as soon as you reach the top.

If you or anyone else wants to interrupt regens for convenience, then have at it, but it shouldn't be advocated as a safe practice, especially when one of the main goals of this site is to maximize engine longevity.

IndigoBlueWagon February 13th, 2015 17:52

I started a drive to New York a few months ago and as soon as I got on the freeway the car went into regen. Stayed there for 30 miles at 75 MPH. Didn't have the cruise set. I was pretty surprised, but all seemed well after.


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