TDI 81kW: No Power & Jerking After Acceleration

Hello,
'On my Toledo with an AFN engine, manufactured in 1998, I'm experiencing the following problems (of course, this is happening during the holiday season when no workshops are open).'
'When starting the engine in cold weather (around 7-10 degrees Celsius), it takes about a minute of cranking before it starts, accompanied by a lot of white smoke and rough running for a few seconds. If the engine temperature sensor is disconnected, it starts much better with less smoke. Also, even when the engine is still warm and has been sitting for about half an hour, the same problem occurs.'
In addition to that, when I give it more gas after a period of deceleration, it doesn't accelerate properly and emits thick black-blue smoke while jerking violently.
If I let the engine speed drop below 1500 RPM (by pressing the clutch) and then accelerate, it returns to normal operation.
Otherwise, I can't detect any loss of power, and the maximum speed is still being reached as before.
Can you give me some advice on how I can proceed myself, or what I should be aware of when visiting a workshop, assuming one is open again? (Bosch Service, VW, Seat?)
I live in the LB area.

Thank you in advance for your efforts!

Hi.

Since problems that occur suddenly or simultaneously usually have a common cause, I suspect the relay 109 or another issue within the Electronic Door Control (EDC) electrical system.

The crankshaft position sensor (CKP sensor) could also be a potential cause.

In any case, I would start by reading the error codes (or having them read). Hopefully, that will provide more information.

Now I've checked the relay 109; the coil is working and closing the contact, and all the fuses are also okay.
Mistakes are still present.
Now we wait to see if any workshop is open somewhere, or we could just try to fix it ourselves in the meantime...
I drove my Jetta 1.6 gasoline engine for 230,000 km with the original engine without any repairs; I sold it two years ago and it's still running. However, the diesel one started having problems at only 130,000 km.
But for now, thank you for your tips.

Hello peak,

Please check the fuel injection timing in the basic setting mode.
Is the timing belt tension okay?
Is the error memory empty? / Is there anything stored in the error log?

Best regards, Rainer.

Sorry.

Unfortunately, I don't have any options for reading data.
'The timing belt tension is okay, but unfortunately, I have to wait until a workshop is open. I'm just not sure what they're going to try to sell me. I know a little bit about cars myself, but when it comes to the electronics and other things, they can tell me all sorts of things.'
It's also a strange error; I'll keep you updated.

Today I went to the friendly Volkswagen dealer because the Bosch service center was determined to completely disassemble the glow plug system (which I quickly declined... uh, excused myself from).
'The error memory only indicated the disconnected temperature sensor. We then continued searching and eventually identified the camshaft wheel and the defective vibration damper.'
I was afraid of that; after studying here in the forum extensively, I had also suspected it.
At this point, I also want to express my appreciation for this excellent forum, and send greetings to the administrator, who comes from my original hometown (a former resident of Roth or Büchenbach sends their regards).

Sorry for the tangent!

'Oh yes, the repair shop quoted approximately €600 for the repair, including labor. Unfortunately, since I no longer have a garage or any other sheltered space, I suppose I'll just have to bite the bullet and pay it.'
Is the price reasonable? I'm completely lost when it comes to car repairs; this is the first car I've owned that's ever been to a workshop.
With previous gas stations, it was usually just a little bit easier.
So then.

Thank you for your help!

peak wrote:

After that, we continued searching and eventually found the camshaft gear, as well as identified the defective vibration damper (is that what it's called?).

Hi.

What tests did you use to identify these errors?

The camshaft wheel was actually never a problem here, as far as I know.
Or are you referring to the crankshaft timing belt sprocket? I believe that loosening was a problem practically exclusive to the 1Z engine...??

I am not aware of any suspension damper that affects the starting behavior in the AFN model .

Crankshaft, not camshaft, nonsense... thanks for the clarification.
I'm probably still shocked by the price.
The Häehnlein report mentioned '1Z' and 'AFN,' possibly referring to a part of the shock absorbers.
Well, I still need to take some extra lessons, but I'm increasingly realizing that the TDI is very different from my preconceived notions of diesel engines and incorporates a lot of technology and electronics.
I hope you'll forgive my amateurish behavior. But I am willing to learn.
I always pushed the technician to adjust the settings towards the start of the injection process because of the starting behavior, which then led him to focus on the vibration damper, or rather, the 'shock absorber.'


Sure, here's the translation:

'Thank you.'

peak wrote:

Crank. I hope you'll forgive my amateurish behavior.

But I am willing to learn more.

Hi.

No problem... as long as people don't keep asking the same questions in the forum, especially when there are already enough expert articles on Rainer's website

Quote:

.

I always pushed the technician to adjust it towards the beginning of the injection process because of the starting behavior, which then led him to focus on the vibration damper, or better said, the "shock absorber."

There is likely a torsional damper located on the crankshaft pulley, within the timing belt wheel, for components like the alternator (LiMa).

But if only :!:this damper is broken, it doesn't necessarily mean that the gear on the crankshaft will be damaged }.
In my opinion, this error can only be reliably detected by checking the engine control unit or by logging and analyzing the desired and actual values of the injection start using a VAGCOM device while driving.

What exactly did the technician check?

Hi,

So, after checking the error memory and finding only 'mass airflow sensor' (MAF sensor) as the stored fault, and considering that the car wouldn't start at all, that was the service advisor's initial suspicion, which he checked first, but not using VAG-Com.
Interestingly, the LMM error also disappeared after the repair.
I wasn't present when the parts were replaced, but I received the parts today, along with a printout detailing the fuel injection timing settings.
The bearing of the torsion spring (I believe this is the rod to which the roller is attached) and the roller itself were replaced.
Is the crankshaft timing belt pulley, or the entire large disc with the plastic insert, also a type of vibration damper?
Certainly, there were a lot of metal shavings inside the timing belt pulley, and the groove was completely worn out. The crankshaft had been reworked, he said it had been machined.
What surprises me is that I hadn't noticed before how much the electronics can compensate for while driving.
It started with the starting problem, and about two weeks later, there was also the issue of power loss after acceleration.
Ich bin ja kein Heizer, und auch kein Gefühlsdepp das ich nicht merken würde wenn mit dem Motor was nicht stimmt. EThat's strange.
Oh yes, the technician also mentioned that due to the defective shock absorber (or whatever the cause), such forces would act on the wheel, which could lead to it shearing off.
Except for the bill, I have to say that I was very satisfied with the workshop! Although it wasn't a VW, the service manager tried very hard.

See you later.

peak wrote:

Certainly, there were a lot of metal shavings inside the timing belt pulley, and the groove was completely worn out. The crankshaft had been reworked, he said it had been machined. What surprises me is that I hadn't noticed before how much the electronics can compensate for while driving. It started with the starting problem, and about 2 weeks later, there was the issue of power loss after acceleration.

Hi.

Now, at least it's clear that the gear was actually worn out.
The electronics have limited compensation capabilities. Typically, the injection timing adjustment requires its entire control range to be able to set the desired injection start time in all operating conditions, even with correct control timings and pump settings.

If, for example, a defect causes only a few degrees of deviation in the "late" timing range, it is hardly noticeable during operation because the late timing range is only used at partial load, and an "early" injection start can even make the engine run slightly more smoothly.
While a few degrees missing in the lower range might not seem significant, it can become noticeable as a loss of performance.

All of this, of course, regardless of the effects of the also adjusted valve timing.

The chronological development (initially starting problems, followed by a subsequent loss of power) is certainly typical for a worn or damaged timing belt pulley.

Quote:

The crankshaft timing belt pulley, or the entire large disc with the plastic insert?? Is that also a type of vibration damper?

Generally speaking, as far as I know, yes.

Quote:

The housing of the torsion spring (I believe this is the rod to which the roller is attached), and the roller itself were replaced.

If you're referring to the pivoting arm with the roller that uses spring force to tension the alternator belt, then that's just the tensioner, but not a damper.

Quote:

Oh yes, the technician also mentioned that due to the defective shock absorber (or whatever), such forces would act on the wheel, and this could cause it to shear off.

That seems unlikely based on my initial impression.
Ultimately, the LIM (likely the heaviest belt-driven component), probably has a freewheel mechanism, meaning that any rotational unevenness of the motor will likely only cause force peaks in one direction, which should make it more difficult or prevent shear forces.
Especially since the belt's inherent elasticity helps to dampen force peaks.

Do you still have the broken torsion damper (pulley wheel)? Could you please describe whether the inner and outer parts can be easily rotated against each other until they reach a stop somewhere?

Hello Ulf,

I've now checked the gear; specifically, I examined the inner part (where the ribbed belt sits) and the outer part (which is for the timing belt).
The two parts can be shifted relative to each other by approximately 5 mm.
Are they not securely fastened? I'm starting to feel a little embarrassed by my lack of knowledge.

My question is, how can I avoid this happening again in the future?
Can I periodically tighten this screw, or is it a stretch bolt that needs to be replaced each time?
I'm kind of worried, especially because the 'Welle' (presumably a product or service) has been redesigned, and it seems like at least 1/10 of its functionality is missing.

Thank you in advance!

Hi,

Well, to be honest, I don't understand what could possibly go wrong with a vibration damper... although I've heard that before.

It's possible that material defects are the cause, but I believe that overtightened (or undertightened) internal hex screws (25 Nm for 1z, afn, aaz) can cause this problem by stripping/loosening.

It's actually difficult to install the shock absorber incorrectly because the arrangement of the screw holes on the KW sprocket only allows for one possible way to mount it.

@peak:

Take a look at the crankshaft pulley... you'll see a single (!) round protrusion between two screw holes. On the damper (ribbed belt pulley), there is a hole in this location (so that the damper sits flush). Take a look at this hole to see if it's still round or worn out... then, a problem with the four screws is likely .

Best regards, Christian.

peak wrote:

I've now checked the gear; specifically, I examined the inner part (where the ribbed belt sits) and the outer part (which is for the timing belt). The two parts can be shifted relative to each other by approximately 5 mm. Are they not securely fastened? I'm starting to feel a little embarrassed by my lack of knowledge.

Hi.

*gg* I haven't had a disassembled shock absorber in my hands before .

I think that the only meaningful damping function could be achieved by allowing the mounting part and the wheel to rotate against each other against a spring force .

If rotation is possible without any damping, the entire system will constantly oscillate between its extreme positions during operation, which increases peak forces and could potentially lead to localized overloads...

If anyone knows more about the structure and function, please post }.

Hi peak,

If you have the opportunity, please take a picture of it and link it here.

Best regards, Andy.

ulf wrote:

*gg* I haven't had a disassembled shock absorber in my hands before . I think that the only meaningful damping function might be achieved by allowing the mounting part and the wheel to rotate against each other under the influence of a spring force

.

Hi Ulf,

So, I've held a few shock absorbers before, but I'm currently unsure . If I remember correctly, there are no springs inside that particular shock absorber. The damping is only achieved through the material – it's a solid piece .

Best regards, Christian.