ASZ Engine Performance Issues: Troubleshooting & Logs

Hello,

"I'm having the following problem... for the past 3-4 days, my vehicle hasn't been pulling at all; there's no power. About 30,000 km ago, I had a similar issue with the maximum speed, and thanks to your help, I replaced the mass airflow sensor, which resolved the problem. Now, I can hardly imagine that it would be defective again after such a short time. The symptom is a maximum speed of about 150 km/h, no acceleration above 2000 RPM; it's really struggling. Perhaps someone can help me. I did two diagnostic tests, once with codes 3-8-10 and 8-10. Unfortunately, I don't remember which one was the relevant code. If it's still important, the EGR valve is deactivated, which I did thanks to your help."

Thank you very much for your help.

MWB 3-8-10

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MWB 8-10 (This likely refers to a specific product or standard and should be kept as is.)

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"Yes, the LMM [likely mass airflow sensor] is probably faulty. The measured values are far too low (field 3 of MWB3 is not reaching 2). Is some kind of useless, cheap aftermarket air filter being used?"

Greetings, Rainer.

hello,

no, no sports air filter is being used, nor a chip or anything similar; everything is completely original. It's really a disgrace; the new one didn't last long at all .

Where did he get that from... eBay?

Is there a problem with the air intake before the air filter? Is the air filter noticeably "dirty"?

hello,

So, to my dismay, I just bought a new spark plug for €98.77 directly from VW, and absolutely nothing has changed. Of course, I immediately went for a drive, but there's no improvement; the engine feels exactly as weak as before, maybe slightly better, but that would probably be in the single-digit percentage range. What now? Should I measure any other parameters to try to figure out what's going on?

It really shocked me a bit; I thought that would solve the problem.

Thank you very much again for your replies.

best regards, martin

martsch wrote:

What now? Should I measure any other parameters to try and figure out what's going on?

Normally, a high LD value with poor LMM values, despite functioning electronics, usually indicates a vacuum leak between the MAF sensor and the compressor. Or (less commonly) it could be due to a severely clogged exhaust / catalytic converter.
I would start by checking the suction line for leaks.

The boost pressure curve is strange. Also, it has overboost up to 1.7 bar.

hello,

I'm having this problem. Nevertheless, thank you very much for your answers. When I was driving along the intake manifold, I took a closer look in the engine compartment, and that's where I found the culprit. It's the EGR valve again, that damn plastic part that holds one of the levers has broken off again. It was hanging halfway, and it probably wasn't enough to trigger a limp-home mode like it did for me before, because this plastic part has already broken on my car once.

Despite everything, thank you for your efforts. I just wanted to mention the source of the problem here, because I don't like it when people help someone and then the person who started the thread doesn't explain what the issue was in the end.

Best regards,
Martin.

Hello martsch!
I think it's great that you posted the cause; that's what makes a forum really useful.
Best regards, ammerlaender!

Hi,

Quote:

damn plastic part that holds this lever in place

Do you mean the lever from the shut-off valve? It's located in front of the EGR valve, which would make sense.

Best regards, Rainer.

hi,

Yes, exactly, I mean the lever from the parking brake.

best regards, martin