Strange performance loss on the 1Z

Hi,

I'm almost bored, and my tools are already starting to rust... but it looks like there will be work again .

Regarding the issue:

Zur Zeit plagt mich ein seltsames Phänomen. Ca. 5-7 min nach dem Kaltstart habe ich manchmal plötzlich keine Power mehr im Drehzahlbereich zwischen 900 und 2500. Zur genaueren Beschreibung: Der Motor startet kalt (und warm) einwandfrei und der Turbo setzt wie gewohnt bei 1500 rpm ein (kalter Motor; AGR kaputt). Wenn ich dann nach 5-7 Min auf die Autobahnauffahrt (ausgerechnet dort) komme schafft es der Wagen plötzlich nur noch mit ach und krach auf 80 kmh zu kommen (->keinerlei Durchzug). Beim weiteren Gasgeben setzt dann langsam wieder der Durchzug ein (>2200rpm) und danach ist alles wieder bestens. Nach erreichen der Betriebstemperatur fährt der Wagen auch wie gewohnt. "What's also strange is that this problem only occurs on my usual route, specifically in the..."It occurs when entering the highway . The problem only happens sometimes. What could it be?

The fault memory only contains the two permanent faults 00625 and 01117.

I am unfortunately unable to perform a test run at the moment, as my laptop battery only lasts for a maximum of 5 minutes. Does anyone know where I can get an inexpensive converter (inverter) from 12V to 220V~ ?

Thank you very much in advance .

hi,

I can only use a power supply that converts from 12V DC to a variable output of 15-24V DC. You can find them on *bay for around 20 euros. It works great for me!

Regarding your performance issue, I'm unfortunately unable to assist you with that as it seems to be a very infrequent problem.

Hi Erik,

haehnlein wrote:

Wenn ich dann nach 5-7 Min auf die Autobahnauffahrt (ausgerechnet dort) komme schafft es der Wagen plötzlich nur noch mit ach und krach auf 80 kmh zu kommen (->keinerlei Durchzug). Beim weiteren Gasgeben setzt dann langsam wieder der Durchzug ein (>2200rpm) und danach ist alles wieder bestens. Nach erreichen der Betriebstemperatur fährt der Wagen auch wie gewohnt.

Hi Christian,

Since you haven't mentioned anything about boost pressure, I would initially attribute the problem to this complex of causes (e.g., a partially stuck wastegate or something similar). It is possible that boost pressure gradually builds up again in the higher RPM range.

-> If you don't have an LDA, your car is probably now a typical confirmation of the corresponding article (click on my signature).

ulf wrote:

da Du nix zum Ladedruck schreibst, würde ich das Problem aus dem Bauch raus erstmal diesem Ursachenkomplex zuschreiben (halb offen klemmendes Wastegate oder etwas in dieser Art).

Hi Ulf,

I've also considered the wastegate valve. When I removed the cylinder head last year (shortly after buying it), the turbocharger looked brand new (sparkling clean). Of course, that doesn't rule out the wastegate. However, I have to admit that I'm currently driving very little. With a fuel consumption of 4.1-4.3 liters, you can imagine how I'm driving (just on the highway behind a truck).

The day before yesterday, I revved the engine to a constant speed of 170 km/h, and since then, the problem hasn't reappeared. The question now is whether consistently driving at low speeds could cause the wastegate to become clogged . However, if that were the case, the problems probably wouldn't be in the area of the linkage/diaphragm housing, but rather with the valve inside the turbo (due to carbon deposits) .

But I see your point... as a forum participant, it's almost mandatory to have an LDA (Low Distortion Amplifier). I need to look into that sometime soon.

@haehnlein:

I can definitely imagine that the wastegate valve inside a turbocharger could become clogged with carbon deposits if the machine is consistently operated at low RPM and under light load.
I deliberately rev the engine (when it's warm) to a minimum of 3000 RPM with full throttle at least once per trip to move the wastegate.
A single instance of full-throttle acceleration should only slightly increase your average fuel consumption, if at all, but it helps ensure the proper operation of the wastegate (or reduces the likelihood of its failure).

Regards,
Alex.

I'm going to tackle this problem now.
Ich bin vorhin los gefahren, nach maximal 1km kam eine Kreuzung. Ich wollt da losfahren, da bemerkte ich, dass die Anfahrtsschwäche etwas stärker war als sonst, na gut ich hatte ja auch den Kofferraum beladen. Also gab ich mehr Gas und das Auto sprintete mit einsetzendem Turbo mächtig los. Nachdem ich in den 2ten Gang geschaltet hatte, nahm der Motor kein Gas mehr an. Ich war mit dem Fuß auf dem Boden, aber er rollte nur vorwärts von dem Schwung den er noch hatte. ILooking in the rearview mirror, I could see that the entire road behind me was filled with thick, black smoke. (Now I finally know what a diesel engine looks like when it's producing excessive soot.)
Suddenly, it started accelerating again, and I could continue driving normally without any black smoke. Earlier, I warmed up the engine again and checked to see if I could detect any loss of power, but there was none. The only thing I noticed was that it seemed louder, almost "knocking," than usual, especially in the range around 2000 RPM, and this knocking sound was higher pitched.

I'll stop by the Volkswagen dealership tomorrow to have them read the error codes. There should be an entry there, I think. By the way, the problem didn't occur again during the second cold start earlier.

@x world one:

What you're describing sounds like a stuck EGR valve to me.
Try temporarily disabling the EGR valve (ideally with a piece of metal). If the problem then disappears, you'll know what was causing it.
Black smoke and loss of power don't sound like a wastegate valve issue.

Regards,
Alex.

donalexo wrote:

Das, was Du da beschreibst, klingt für mich nach klemmendem AGR-Ventil.

Hi Alex,

I also think it sounds like an AGR issue. Mine doesn't produce any smoke, though . However, I thoroughly cleaned my turbo once, and since then, the problem hasn't reappeared. So, it seems that the wastegate really does get clogged over time... Well, as long as it goes away with a good cleaning .

Thank you, I'll give it a try.

So, it seems that the EGR valve is not the cause of the problem in my case, but rather the alternator.
The error no longer occurs, but other things have happened instead .

I went to the Volkswagen dealership today to have the error codes read. It turned out there's a sporadic fault on pin DFM of the alternator (the technician didn't tell me the specific code, and I couldn't identify it myself).

He said that the control unit would shut down all possible consumers in case of this error, including the glow plug system, to prevent overloading the alternator. This would happen for as long as it took for the alternator to stabilize.

That could theoretically explain the loss of power when the engine is cold, right?

"But what I've noticed is that the engine sounds awful after starting. Also, I have the feeling that it sounds much rougher, especially at lower RPMs, but seemingly only from one cylinder. I can clearly hear it when the car is stationary; it's knocking too loudly for my understanding, although it sounds different than the usual deep diesel knock."
I'm currently at a loss and haven't been able to find any solutions through searching related to the DFM clamp issue.

x world one wrote:

I went to VW today to have the error memory read. It turned out there was a sporadic fault at terminal DFM of the alternator (the man didn't tell me the number, and I couldn't properly identify it myself). He said that the control unit would shut down all possible consumers in case of this error, including the glow plug system, to prevent overloading the alternator. This would happen for as long as it took for the alternator to stabilize. Das könnt ja theoretisch diesen Leistungsverlust erklären bei kaltem Motor oder?

Not really.
The only thing that the engine computer actively switches on, depending on the alternator load, is, in my opinion, the glow plug heating.
The glow plugs remain on for as long as the afterglow phase lasts (-> exhaust gases are more important than the vehicle's electrical system, which is more important than a freezing driver ).

To me, the black smoke coming from your exhaust still points to an EGR problem – it's a classic symptom.

Hm, then I can only observe it now. But what bothers me is this strange engine noise. At least the error hasn't occurred again .

Okay, so tomorrow I'll disconnect the EGR valve again, see if the noises are gone, and if not, then I'll check the alternator or even do a small injector test.

Hi,

"The tip from donalexo seems to be working. Just give it a full-throttle blast once during each low-speed drive, and that's all there is to it. I couldn't believe that the wastegate could get clogged, but the thick clouds of smoke produced when giving it full throttle after driving economically really confirm the theory about buildup."

In my past cylinder head removal experiences, I've consistently observed a thick layer of soot on the valves and surrounding areas. Our Audi 80 didn't have this issue because it was previously driven at high speeds on the highway. It's likely that with the TDI (unlike the older TD), the exhaust system is designed for very large exhaust gas volumes. It would be interesting to know how much larger the exhaust gas volume is at full throttle compared to 90 km/h while driving behind a truck .

Hi,

I think it's reasonable to assume, as a very rough approximation, that the volumetric flow rate through the exhaust system is roughly proportional to the amount of fuel injected.

According to my MFA (Multi Function Display), my ASV (Adaptive Suspension Vehicle) consumes about 4 liters at 90 km/h. When driving behind a truck (which I actually don't do often, as it's too dangerous on the city highway), it probably consumes around 3.5 liters or slightly less.

At full throttle, it's 13 liters, and all figures are given in the 5th gear, making them comparable. This means a volume flow rate that is roughly four times higher.

Best regards,

Jan, who will also be driving about 400 kilometers on the highway next week and can give his exhaust a good blast.

Since I've already started a thread, I'll just continue posting here.
The oil change was done today; I used 10W40 Castrol oil and did an "oil flush" to verschandeln the engine's interior. Well, it definitely didn't hurt anything, and considering how thick the old oil was, I don't even want to know why...

Well, that's about it. After that, the engine ran/is running much better, smoother, and more quietly, and subjectively, it revs up better. Also, the auxiliary noises seem to be improved; I haven't heard them anymore.
Was mir im Leerlauf bei der Ölspülung auffiel war, dass aus Richtung Lima ein eigenartiges Geräusch kam, ähnlich einem Rasseln. Evtl. ist es das Geräsuch was ich bei niedrigen Drehzahlen im Innenraum als Rasseln warnehme? Mittlerweile hört man es sogar rasseln beim anfahren. Jedenfalls war es mir nicht möglich zu bestimmen ob das Geräusch tatsächlich von der Lima kam. Könnte das auch die Spannrolle sein? Das The car now has approximately 172,000 kilometers on the odometer, which means that if the first timing belt replacement was done correctly, it's likely due for replacement again now.

Nach etwas "stressen" des Motors, sprich richtig ausdrehen im 3ten gang und Ulfs Durchzugstest, viel mir auf, dass ich im Leerlauf Vibrationen am Lenkrad und am Bremspedal habe! Ich stand nämlich an einer Kreuzung und war richtig erschrocken als ich plötzlich im Stand Vibrationen im Bein spürte die vom Bremspedal kamen. Auch in den Handflächen merkte ich diese am Lenkrad. Das trat später auch nochmal auf, als ich wieder nach stärkerem beschleunigen einfach mal rechts angehalten habe. Nach normaler Fahrt und anschließendem Anhalten waren die Vibrationen wieder weg, also völlig normal wie immer. SinWhat are the symptoms of a worn-out timing belt and tensioner pulley?
The material probably doesn't cost that much for VW, but the labor time for the replacement is likely quite significant.