Weird behavior from CRD

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

I've had my 06 CRD for about a month now and I've noticed a peculiar sound and behavior from it and want to know if it's normal, or if any of you have encountered it with yours. The sound happens when I drive for enough time to get it warmed up and then shut it off for a period of time (doesn't seem to matter if it's 20 minutes or a few hours, but the engine is not cold). Upon re-start it fires off just fine, but when I take off it sounds extra "diesely" for lack of better terms and almost sounds as if it's missing, but there is no surge like a miss in a gas vehicle. As soon as I crack the throttle and accelerate it smooths out and runs fine, but if I don't open the throttle much it takes a little more time to go away. Also, it seems the longer the drive was before I shut it off the worse it is.

SO, any thoughts? Is this normal behavior?

camo · **Posted:** Sun Apr 08, 2012 9:56 pm

Do you use full synthetic diesel rated oil eg. mobil1 5w-40? Are you following the cool down procedure at the owners manual?

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

Yep, first thing I did was change the oil since I didn't know what the vw dealer I bought it from had put in there. Also I always let the turbo cool but it doesn't change anything.

Why, do you think maybe the turbo isn't spooling up at first when it sits hot? That would be bad...

msilbernagel · **Posted:** Mon Apr 09, 2012 1:32 am

How many miles on the vehicle? Nothing certain, but miles can make certain failures more likely.

How long since the last fuel filter change? If you've sucked in air, it could made for poor idle until you rev it up enough to pull the air out and send it back through the injectors and fuel return (to tank). Some of these rigs have more issues with pulling air in at the tank fittings than others, and a fuel filter approaching end-of-life exacerbates the problem.

Mark

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

I replaced the filter and filter head with the updated version about 3500 miles ago. The thing is it idles great just like normal. It starts making the funny sound as soon as I apply a little throttle. Plus it doesn't do it when the engine is cold, like after sitting all night, and only does it once (not at stop lights or if I shut it down for only a couple minutes) . It's got 90k on it and was bone stock when I brought it home.

sbik100 · **Joined:** Tue Mar 06, 2012 8:18 pm **Posts:** 1

This started happening to me a month or two ago. It would just happen randomly. I assumed it was something to do with the fuel filter or fuel filter head (still has the original fuel filter head). But before I could replace it, I ended up getting GDE's ECO tune and transmission tune... and the problem has disappeared. Not sure if it was just a coincidence or if the tune actually changed something to eliminate the issue.

papaindigo · **Posted:** Mon Apr 09, 2012 12:49 pm

May have been odd noises from the FCV.

msilbernagel · **Posted:** Mon Apr 09, 2012 1:33 pm

So, as a diagnostic only

, you suppose KJH could pull the MAF sensor (airbox) - effectively disabling the FCV/EGR - to see if the odd operation changes?

Any value in his disconnecting the FCV as part of that diagnostic, or does the MAF accomplish the same thihng... ?

Mark

papaindigo · **Posted:** Mon Apr 09, 2012 2:50 pm

He says problem seems to have gone away with the GDE tunes and since the ECU tune largely cuts out the EGR I was speculating that the noise was related to the FCV which ties to EGR use. At this point pulling the MAF wouldn't do anything except throw a code. Now if the noise comes back pulling the MAF might be worth a try as a diagnostic.

msilbernagel · **Posted:** Mon Apr 09, 2012 3:44 pm

I think you're correct re: FCV, but the OP was not the person who mentioned GDE (sbik100) - so I wanted to make that distinction to see if kjhooligan (OP) can get a differential diagnosis ('House' version, not pumpkin/rear-axle).

Mark

papaindigo · **Posted:** Mon Apr 09, 2012 3:54 pm

Thanks for catching my oops regarding the OP's lack of a GDE tune. Yes it's worth trying pulling the MAF, it will throw a code but if the sound goes away that will tell where it's coming from.

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

Pulling MAF makes no difference. We took a trip to Vegas (MAF plugged in) and when it did this weird behavior I decided that maybe I needed to rev it a bit to clear out whatever was happening before putting it into drive and taking off. This threw a low boost code. It seemed to be running progressively worse on the way there so I decided to pull the MAF and it ran ten times better (like normal) but it did not effect the weird behavior on certain start ups. It's been unplugged ever since. I think the egr was sticking so I left it unplugged.

As for GDE, I just took in some scrap today and will be ordering up an ECO tune with the programmer tool here in the next few days, so maybe I'll get lucky and have the same results as sbik100. I just wonder if the turbo is full of gunk.

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

You know, I was thinking about it and I think the FCV and EGR are probably contributing to the problem. When it was running poorly in vegas it basically made the same noise but at a higher rpm a few times. When I unplugged the MAF it ran great, no noise. The dealer went over previous warranty work with me and there was nothing about an EGR, so it's probably running the original EGR and I bet it's hung open a bit. I'll pull it and clean it when I have time.

Does the FCV get full of carbon like the MAP sensor does? Can it be cleaned out too?

naturist · **Posted:** Mon Apr 09, 2012 10:17 pm

Mine does a number something like that . . . for oh, 5-10 seconds it sounds like the valve lifters have not pumped up, but it happens long enough after the engine has started that it can't be that. It seems to be related to the transmission/TC fluid having drained back into the case, as I also get the slipping and inability to disengage that comes with incomplete transmission hydraulic fluid circulation. It always starts, runs fine, clatters, smoothes out, and THEN the TC/tranny behaves perfectly. Doing a drain and flush, refill with new tranny filter always clears it up for a while, then it will start again. Been doing that now for 80K miles at least.

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

Well, I still have no idea why it was doing it but I installed my FT Eco tune yesterday morning and it has totally cleared up, along with a few other little quirks. She's running like a swiss watch. :BANANA:

msilbernagel · **Posted:** Sun Apr 15, 2012 3:27 pm

KJHooligan wrote:

Well, I still have no idea why it was doing it but I installed my FT Eco tune yesterday morning and it has totally cleared up, along with a few other little quirks. She's running like a swiss watch. :BANANA:

That's one happy banana, KJH!

Thinkin 'papa was right about the FCV/EGR, and the 'tune pretty much shut it down!

All that, more power, and better mileage too! Calls for a chorus line! :BANANA:

KJHooligan · **Joined:** Fri Mar 02, 2012 10:45 pm **Posts:** 30

x2! It's got a ton more power everywhere, it's much smoother, and it just feels like it should have been this way from the factory. The torque increase when running down the highway is fantastic.

Weird behavior from CRD

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