Low Power/Torque, Poor AFR: Troubleshooting Guide

Hello,
I have a Passat, first registered in 12/99, model TT5, engine code AFB, with 112,000 km. It has an *** chip, which now only allows a top speed of 210 km/h (previously 240 km/h) and the acceleration is poor . Since the timing belt change, it also seems louder . Now, let's go into more detail:

- The mass airflow sensor (MAF) is providing readings that are too low (it was replaced with a known working unit, but the problem persists).
- According to the VAG-Com timing check, my values are slightly above or exactly at the upper tolerance limit (assuming the displayed table is correct for the AFB engine).

So far, I have checked/done the following: I've ensured the intake passages are clear, replaced the mass airflow sensor (MAF), replaced the diesel and air filters, the variable geometry turbo (VGT) linkage moves freely, and the EGR valve makes a noticeable clicking sound as soon as the vacuum is removed. The exhaust and catalytic converter show no visible damage, and there are no air bubbles in the fuel line.

I've now logged the various groups, and maybe the experts in the forum can tell me where I should continue searching (or have it searched)... according to the information, it could be a cat, AGR, ESP, injectors, dirt, or a turbo ?

Regards,
Dieter.

Group 03: http://www.dhecker.privat.t-online.de/passat/003.jpg
Group 04: http://www.dhecker.privat.t-online.de/passat/004.jpg
Group 08: http://www.dhecker.privat.t-online.de/passat/008.jpg
Group 10: http://www.dhecker.privat.t-online.de/passat/010.jpg
Group 11: http://www.dhecker.privat.t-online.de/passat/011.jpg}

Hello,

Have you also checked the valve timing?

Hello,
How can I check the valve timing? (I couldn't find anything about it in the forum.)

Regards,
Dieter.

Hello,

I assume you didn't do the timing belt replacement yourself, did you?
The camshaft must have a defined position relative to the crankshaft. Therefore, when changing the timing belt, camshaft alignment tools and locking pins are used to precisely align them in the correct positions.

Hello,
'I didn't do the change myself... my parents were on vacation with my car. There was a problem with the engine control unit, so I took it to the workshop. The diagnosis was a defective ESP. After disassembling it and my request for a warranty claim, it turned out to be just a cable. Since everything was already open, I also had the timing belt and water pump replaced.'
The million-dollar question is whether the timing check in the basic settings of VAG-Com is reliable, because in my case, the values are being displayed at or just slightly above the absolute upper limit... if that's the case, then the ESP should definitely be set up correctly, right?

Regards,
Dieter.

Hello,

Since you had it done at the workshop and paid for it,
I'm going to give them a hard time about the car (there are various reports about this in the forum).
If you do something yourself and something goes wrong, no one will pay you for it anymore.

Hello,
I would like to do that, but the workshop is about 500 km away , and my local workshop doesn't have an opening for two weeks .
The only option is probably to contact Bosch service and have them check it.

However, the issue with the LMM values probably isn't related to that, since the values were already like that before (at most, something might have been misconfigured before ).

-> What would such a review at the AFB likely cost?

Regards,
Dieter.

PS: The workshop was probably trying to pull a fast one (the rental car was supposed to cost money despite the mobility guarantee, the ESP was supposedly 100% defective -> but after I intervened/the workshop intervened, it suddenly turned out to be just a cable, and the rental car was free... but you can try that with older people who don't know any better).
PPS: The trigger for the whole incident was a short circuit caused by a damaged trailer cable... but I only found out about that AFTER the incident -> which, of course, I won't mention because it has nothing to do with it.

Hello,

Oh my goodness. I'll send you an explanation about the timing belt replacement, including a check of the timing, which might help you for now.

Hello,
The timing, EGR, turbo, and ESP systems were checked by Bosch Diesel Service and are reportedly okay. However, the mass airflow sensor (including a new one) is only providing readings up to approximately 750 (the target value is 879.2).
-> What should be checked next: fuel injectors (one deviates downwards by approximately 1.6, but is within the tolerance), catalytic converter, or something else???

I'm still getting an error code in control unit 19 (K <-> CAN Gateway, 01044: Control unit incorrectly coded). Could this be related?

Regards,
Dieter.

Hello,

Are the camshafts worn?

Best regards, Rainer.

Hello,
I can't say for sure because the covers haven't been removed yet -> would my AFB (Automatic Bevel Face) be considered for the worn camshafts? I've read that it's typically recommended around 150,000 km, but I can't do anything with the vehicle identification numbers .

Regards,
Dieter.

Hello,

Please send me your vehicle identification number (VIN) via private message, and I'll take a look.

Hello,

Your vehicle identification number (VIN) might be a candidate for this issue.
But before you take it to the workshop, I would first take a good look at the camshaft myself.

Regarding your production timeframe, there's something else I'd like to mention.

"Sudden noises accompanied by power loss."

Cause:
Due to irregularities in the valve manufacturing process, damage to the valve disc may occur in isolated cases.

Solution:
"Parts exchange"

Hello,
I have a Passat, first registered in 12/99, model TT5, engine code AFB, with 112,000 km. It has an *** chip, which now only allows a top speed of 210 km/h (previously 240 km/h) and the acceleration is poor . Since the timing belt change, it also seems louder . Now, let's go into more detail:

- The mass airflow sensor (MAF) is providing readings that are too low (it was replaced with a known working unit, but the problem persists).
- According to the VAG-Com timing check, my values are slightly above or exactly at the upper tolerance limit (assuming the displayed table is correct for the AFB engine).

So far, I have checked/done the following: I've ensured the intake passages are clear, replaced the mass airflow sensor (MAF), replaced the diesel and air filters, the variable geometry turbo (VGT) linkage moves freely, and the EGR valve makes a noticeable clicking sound as soon as the vacuum is removed. The exhaust and catalytic converter show no visible damage, and there are no air bubbles in the fuel line.

I've now logged the various groups, and maybe the experts in the forum can tell me where I should continue searching (or have it searched)... according to the information, it could be a cat, AGR, ESP, injectors, dirt, or a turbo ?

Regards,
Dieter.

Group 03: http://www.dhecker.privat.t-online.de/passat/003.jpg
Group 04: http://www.dhecker.privat.t-online.de/passat/004.jpg
Group 08: http://www.dhecker.privat.t-online.de/passat/008.jpg
Group 10: http://www.dhecker.privat.t-online.de/passat/010.jpg
Group 11: http://www.dhecker.privat.t-online.de/passat/011.jpg}



Hello Dieter,

'I experienced the same symptoms with my 1998 Passat AFN, with 200,000 km on the odometer after the timing belt change, which I unfortunately had done at a SEAT dealership. I assumed that a workshop that also installed the same engine would be able to solve a common problem. The subsequent story would be too lengthy to recount here, but it eventually led to a lawyer being involved.'
Ultimately, the valve timing and fuel injection timing (which were still within tolerance) were misaligned. Even after correcting the fuel injection timing, the car felt sluggish and was louder than before. Therefore, I had a VW workshop, which seemed to know what they were doing, completely replace the timing belt (along with adjusting the valve timing and related components).
After that, the car ran smoothly again (as much as one can say that about a diesel), and had its full power back. Additionally, the electro-pneumatic converter for the VTG had been replaced (previously), but this had not brought any real improvements.
I believe that the SEAT workshop did not use two feeler gauges to precisely adjust the clearance when installing the camshaft alignment tool, which caused the camshaft to be slightly misaligned with the fuel injection pump.
I cannot say whether this also explains why your LMM is providing low readings and why your CAN gateway is displaying an incorrect coding for a control unit.
It's definitely worth taking a closer look at the issue with the CAN gateway, because if a peripheral control unit isn't addressed correctly, or if the data isn't read correctly, it can lead to 'unintended' corrections by the engine control unit.

Best regards from the north...

Hello,
vielen Dank erstmal für die schnellen und guten Infos ....ich hab bei mir jetzt nochmal den Notebook drangehängt und mit VAG-Com den Timing-Check gemacht -> zeigt der mir falsche Werte (bzw. ne falsche Tabelle für den AFB) oder haben die Bosch-Leute nix gemacht? So It looks like this:

http://www.dhecker.privat.t-online.de/passat/timing.jpg

Regards,
Dieter.

Hello,

At the AFB (presumably a specific organization or institution), a different procedure is required for the hiring process.

Measurement block "Function 08", display group 07, engine idling.


Check the display in field 4 (coolant temperature). Setpoint: at least 85 °C.

Initiate basic setting for display group 04, engine idling.

Advertisement:
850/min, delayed, 1.5, 5 minutes overtime, 100%.

Setpoint field 4: 100%.

Field 2:
Setpoint: "late".

Field 3:
Set Point: 2 °C ± 2 °C.

If the target value is not reached:

Adjusting ESP and checking the timing belt tension.