Power feels low until sudden power boost at 2k rpm

Sella Turcica

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UPDATED: Power feels low until sudden power boost at 2k rpm - N18 EGR valve malfunc'n

Our 05.5 jetta tdi dsg is on all-original parts at 95k miles. This isn't a new issue, and it in fact might just be the nature of the beast, since we're only talking about 100 hp here. I just want to know if something is amiss, or if it's just the turbo kicking in on an otherwise puny engine.

When I start moving from a dead stop and press the accelerator moderately, it feels somewhat unresponsive until I hit about 2k rpm and then it's just like a big power boost until about 3k rpm. I'm not getting any CELs or misbehavior. The car just feels slow and lumpy. Frankly, this is how my old high pressure turbo volvo used to drive every day, but the jetta feels a lot slower.

Yeah, I know it could be the cam, but if that's the case I'll replace the cam when it's trashed. I'm wondering if there's something simpler to check (you know, hose X that runs from point Y to point Z pops off/fills with gunk/etc).

UPDATE 1: 1.5 months later, power loss noticeable, see page 2.
 
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05_new_jetta

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I would say check your vnt actuator movement and make sure that it is free, might be sticking vanes I dunno.
 

DanG144

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It is very probably the overly aggressive EGR operation on the BRM. This limits fueling until about 2k rpm or so.

Will you make it to the Asheville GTG? If so, we can look it over, take some logs. See what we see.
 

fase2000TDI

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Why are you trying to make power below 2K rpm?

Your torque curve is from 2K~3K. Otherwise, you're just lugging the engine.

I try not avoid accelerating below 2K and shift at 3K rpms minimum. It won't hurt the car or your fuel economy.

Though, this happens in first gear? I don't know what to make of that - you should be able to race through 1st.
 

MyAvocation

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There's nothing wrong your car. What you're experiencing is normal diesel hesitation until boost kicks in, which I believe is 1900 RPM.
 

Sella Turcica

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05_new_jetta said:
I would say check your vnt actuator movement and make sure that it is free, might be sticking vanes I dunno.
What on earth is a vnt actuator?

When is the asheville meet?
 

Harvieux

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If this initial low power till 2K rpm is in conjunction with black smoke, I would suspect the turbo actuator issue we have been discussing here lately. Later!
 

philip_g

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MyAvocation said:
There's nothing wrong your car. What you're experiencing is normal diesel hesitation until boost kicks in, which I believe is 1900 RPM.
x2

I think folks are a little too quick to throw out big expensive fixes for problems that might not exist.
 

Sella Turcica

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well, I appreciate free advice from all who suggested things (whether they are simple or not). The car is definitely livelier sub <2k rpm when in sport mode (I had never bothered to compare it in D versus S before). It might just be laggy throttle response or something. I'll keep any eye on it.
 

Windjammer

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Have your wife drive in S mode for a couple weeks & see if that helps. If not, use VCDS to reset the transmission controller.
 

740GLE

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how does the intake look? if it's slightly clogged it wouldn't help anything.
 

Sella Turcica

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power loss!

OP UPDATE:

The original symptom I posted about over a month ago just evolved into something more drastic. I have a definite power loss. I had not yet checked into any of the above suggestions yet due to time constraints, but I will now! I'm looking at purchasing a VCDS/VAGCOM. The car now has 97k miles. What I'm wondering is, does anything below narrow it down a bit?

We got on the road this morning and I started shifting it in manual mode (DSG). I was shifting at low RPMs (2k or so) with the engine just warmed up. I went into 4th gear at a reasonable speed and something clattered. It almost sounded like a bucking manual transmission but worse. The car only did that once.

Also, it was very clear that there was very little power under 2200 rpm, more apparent when going up hills. For instance when I press the accelerator at 1300 RPM, I hear a constant whistling whine and the car accelerates - slower than usual, with more depression of the accel. pedal than usual - all the way until 2200 RPM, where it literally feels like something "catches". Suddenly at that point, the whistle goes away and the car instantly feels LESS boggy, and it feels like there is a burst of power, because I've had the accelerator pushed far in during the "boggy less-than-2200rpm stage" and the car no longer needs that.

Most of the power loss occurs below 2200rpm, yet I recall one point driving up a hilly highway at a good rate of speed in 4th gear over 3000 rpm with the accelerator to the floor, realizing that I was barely maintaining.

The MFD is silent, the gauges don't suggest anything either. It doesn't matter what transmission mode or gear I'm in, the symptoms are the same - noticeable on flat land, problematic on hills. I don't notice any excessive smoke, but this car typically does put out a small puff of black smoke at certain times when accelerating.

I ask if this makes the diagnosis clearer because we're on vacation and if we don't make it back home...
 
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DanG144

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Holler if I can help.
Inspect the cam?
Close off the EGR?
Ensure the catalytic converter is not plugged.
Ensure the turbo controls are set up and working properly.

Standard BRM stuff, it seems.
Dan
 

Sella Turcica

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Holler if I can help.
Inspect the cam?
Close off the EGR?
Ensure the catalytic converter is not plugged.
Ensure the turbo controls are set up and working properly.

Standard BRM stuff, it seems.
Dan
Thanks Dan.

I inspected the cam at about 85k mi, and while there were copper oil streaks and some scarring on the lifters, the chamfer was will present. The car has 97k mi now. When we get home, if everything I check out is equivocal, I'll pull the VC again and revisit the cam.

I'm going to pull the splash guard and see if the EGR is covered in soot - is this how you'd "test" it? I read on this forum of an EGR block or something, but I have no idea what that is. I would be willing to try it.

I'm ordering the 20k service package a little early in case it's just a clogged filter, but my power loss is down low and it feels normal at higher revs so the fuel filter is further down on my differential diagnosis list.

As for the cat and turbo controls you speak of, are those something I can check with a VAG-COM or does that require manual labor?

I ordered the ross tech micro-CAN VAG-COM this morning, should arrive by the time we get home.
 

mattds

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I think it's just he nature of the beast. I have a stage 2+ tune and it helped a lot, but i still notice on hot days with the AC on that the power delievery is not smooth.

Someone mentioned a transmission controller...and resetting it...what is this?
 

Sella Turcica

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I think it's just he nature of the beast. I have a stage 2+ tune and it helped a lot, but i still notice on hot days with the AC on that the power delievery is not smooth.

Someone mentioned a transmission controller...and resetting it...what is this?
Initially I considered it the nature of the beast, since I posted over a month ago and agreed with that... until it became apparent to me recently that there was an even more significant power loss. All of that beautiful low-end torque is just gone.

As for the transmission controller (DSG), isn't that something you reset with the VAG when things get lumpy? I'm curious to know what it is too.
 

Rod Bearing

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Check the intercooler tubing at each connection point. They are held in place by a C Ring and have been known to become partially dislodged, causing loss of boost. You mentioned a noise that may be air leaking under pressure at one of the connection points. The one at the turbo inlet is the first place to check. .
 
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fase2000TDI

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wow. You're lugging the hell out of your engine and it's not running right.

I'm not sure why everyone is looking for a solution to a "I have no power in 4th gear below 2,000RPMS, why doesn't 1300 rpms feel powerful!?" With all that lugging, you've likely clogged your intake manifold quite a bit. You've taken a non-issue by driving your car improperly and created one. It's not a long stroke v8 - it's a short stroke 4 cylinder turbocharged direct injection diesel. Drive it from 2K on and shift at 3. Your car will thank you. I shift no earlier than 3K ever, and I often bring it up to 4500RPMS. My last trip at 75~80MPH returned me 48.3MPG. You have NOTHING to gain by lugging your engine, and everything to lose.
 
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Sella Turcica

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wow. You're lugging the hell out of your engine and it's not running right.

I'm not sure why everyone is looking for a solution to a "I have no power in 4th gear below 2,000RPMS, why doesn't 1300 rpms feel powerful!?" With all that lugging, you've likely clogged your intake manifold quite a bit. You've taken a non-issue by driving your car improperly and created one. It's not a long stroke v8 - it's a short stroke 4 cylinder turbocharged direct injection diesel. Drive it from 2K on and shift at 3. Your car will thank you. I shift no earlier than 3K ever, and I often bring it up to 4500RPMS. My last trip at 75~80MPH returned me 48.3MPG. You have NOTHING to gain by lugging your engine, and everything to lose.
I rev high pretty often. When I drove an old BMW it was customary to burn off carbon deposits that way, even driving around town. I typically shift at 3-3.5k, unless I'm in a hurry and then it's higher. You suggest that I'm lugging the engine - my problem is that the engine is lugging me.

I'm not expecting a 1500 rpm miracle. I have a dramatic loss of power in an RPM range where I used to have more power, and I don't know why yet - that's the real issue here.

As far as the intake is concerned, I plan to check it as well as run the VCDS, check the fuel filter, etc... I have a long list of things to examine until I find the culprit. Thanks for the advice.
 
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Sella Turcica

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UPDATE again:

So when my vag-com arrived today I ran a scan, which is posted below. Does the fault frequency of "1" mean I shouldn't worry about it, or does it mean that "one fault is good enough to clean it or swap it out"?

I also completely forgot to mention that during the "bad" power loss episode, the cruise control stopped working. I read somewhere on this forum that this means the car went into "limp" mode. I never got a CEL, for what it's worth. I recall that I've been slightly down on power for a while until I gave the car a good run in the mountains (an italian tune-up, so to speak) and it went into limp mode. The VAGCOM doesn't put a timestamp on the failure so I can only guess that it caused limp mode the next morning. Do you all think I dislodged some gunk and it messed up the solenoid?

Since the car behaved well yesterday but behaved poorly the day before, perhaps it's only an intermittent thing. Would it be detrimental to drive the car, say, another 20k miles until the next DSG service? I do the regular 10/20k services on my own.

Apparently N18 isn't the EGR cooler valve way down under the car (like I thought) but instead is an electrical solenoid that is inserted in the round intake part between the intake manifold and the "throttle body". It looks like I can't remove it without taking off the those two round metal pieces (again, they are sandwiched between the intake manifold and the large rubber hose.) Do I have to take all of that off just to examine the N18? Apparently I will need replacement gaskets, and after reading the threads about buildup and dislodging stuff into the engine I'm a little wary. Even more frustrating is that I cannot find anywhere online that sells the N18 EGR valve, so it's not like ordering a new one is a snap.

I have literally searched all day on Google, the Bentley, on TDIclub and Vortex. What would a wise person suggest I do now?


All other things looked fine so I cut it out for simplicity:

1 Fault Found:
001027 - EGR Valve (N18): Malfunction
P0403 - 000 - - - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 1
Time Indication: 0

Freeze Frame:
RPM: 1764 /min
Speed: 54.0 km/h
Duty Cycle: 0.0 %
Voltage: 14.36 V
Mass Air / Rev.: 155.0 mg/str
Duty Cycle: 36.7 %
Bin. Bits: 00000000

Readiness: 0 0 0 0 0
 
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Sella Turcica

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I pulled off the rubber hose and looked inside the throttle plate body, there's barely a coating of soot on the throttle plate after 97k miles and barely any oil in the thick rubber hose, so I'm starting to doubt that it got all gunked up.

Upon further inspection of the car, also find that the object between the throttle plate and the intake is the EGR valve. Attached to it is a black plastic thing with an electrical connector. On the metal part, there's a part number 03G 131 502, and on the black plastic thing 03G 131 501 D V 435. It seems like I have to buy the whole thing as a unit. It also seems like the 03G 131 501 D and N are the same part. Prices are really varied, $250-330. Does anyone have any suggestions before I buy the part - ie: does it work to clean these things with a solvent/etc? :confused:
 
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A5INKY

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I would remove the EGR valve from the manifold and clean it before considering replacement. Many threads here on the topic for you to search as it is a known BRM issue.
 

Sella Turcica

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I searched through a few but I know how finicky these cars are so I'm paranoid - can I use some good old throttle body cleaner all over the EGR, as I suspect? ...or will I get a code for "EGR shorted out by idiot cleaning" :rolleyes:
This is my first diesel and I'm willing to learn, it's just that at every turn something is different than with the gasser.

I also noted that people tended to break things while taking off the EGR but that looked like earlier models. I felt around behind the throttle body/EGR/intake and it doesn't appear that I'm going to break anything, it seems as though nothing is attached except the electrical connector. I hope that's right.
 

A5INKY

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Paranoia is not good, due care is. It is not too hard to remove the EGR valve and clean it w/o hurting anything. There are two larger bolts (allen head, I think) that attach the exhaust supply tube from the cooler (flex SS) to the EGR (on the passenger side back and angled down) of the valve, remove those bolts to free that connection. Carefully unplug the electrical connector. Remove the small bolts on the backside (either allen or torx, don't remember) holding the valve to the intake manifold and slide the EGR valve out of the manifold.

You will now be able to see if the valve is fouled and being held open to leak by carbon build up. Unless it is super clean and sealing well (not likely) carefully clean with small scraper, scotchbright pad and electrical parts cleaning solvent until nice and clean. Install in reverse of disassembly, careful with the sealing o-ring around the valve itself and the small gasket for the supply tube.

If the EGR was leaking would cause excess black smoke and lack of power. A good cleaning might fix it right up.

If this seems too involved, get some help from a trusted guru from this forum for troubleshooting. Even if you clean the valve, there may be other stuff going on. An experienced guru will find faults and repair the system, not just focus on component replacement.

Good luck!
 

Sella Turcica

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Paranoia is not good, due care is. It is not too hard to remove the EGR valve and clean it w/o hurting anything. There are two larger bolts (allen head, I think) that attach the exhaust supply tube from the cooler (flex SS) to the EGR (on the passenger side back and angled down) of the valve, remove those bolts to free that connection. Carefully unplug the electrical connector. Remove the small bolts on the backside (either allen or torx, don't remember) holding the valve to the intake manifold and slide the EGR valve out of the manifold.

You will now be able to see if the valve is fouled and being held open to leak by carbon build up. Unless it is super clean and sealing well (not likely) carefully clean with small scraper, scotchbright pad and electrical parts cleaning solvent until nice and clean. Install in reverse of disassembly, careful with the sealing o-ring around the valve itself and the small gasket for the supply tube.

If the EGR was leaking would cause excess black smoke and lack of power. A good cleaning might fix it right up.

If this seems too involved, get some help from a trusted guru from this forum for troubleshooting. Even if you clean the valve, there may be other stuff going on. An experienced guru will find faults and repair the system, not just focus on component replacement.

Good luck!
Thanks a bunch - unfortunately there aren't a lot of gurus around here so I'll do my best. Paranoia comes from working on a bunch of old European cars for years. I assume at every step of the way there's a special tool, or a wrong way to do something. :D

Great quote by the way - one of my favorite movies.
 

A5INKY

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I assume at every step of the way there's a special tool, or a wrong way to do something.
That's for sure. I have ran into this more than a couple times working on VWs. Fortunately not the case with our EGR valves.

Want to read up on fun with obscure tools? Check out the sticky about rear main seal replacement. That was a fun one...:rolleyes:
 
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