Hey everyone.
First of all let me introduce myself; I'm Leon, 23 years old and the proud owner of two mk3 Golfs (one used to be my first car, now used for parts mainly).
However, my 'newer' 1996 mk3 has developed a bit of a nasty engine noise. Now, this is all pretty new to me and I'm still trying to learn things, so bear with me.
The engine I'm talking about is the standard 1.8L mono-injected petrol.
Now this only occurs when I accelerate in third or fourth (01M automatic trans) from like 1500-2300rpm. In other words; when the engine is under load. Also happens a lot more in hot weather, or when the engine's in operating temperature (also keep in mind the engine is not overheating, coolant keeps steady at a nice 90 degrees Celsius). This is the noise I'm talking about:
http://youtube.com/watch?v=iQ1A5jS0RgsSo, after some googling I came to the conclusion that this might be engine knock or pre-detonation, right? Can anybody confirm this?
I investigated a little further, and bought a cheap OBD/VAGcom cable. I went and scanned my car with VCDS-lite, and was happy to see that no fault codes were found. However this didn't really help me much since I still didn't know what's wrong.
Together with a friend of mine, I did a couple of test runs to collect some data through VCDS. One suspicious thing that I noticed is that the Lambda value stayed at a steady -2.3%. Now I don't really know what that means, but does that mean the oxygen sensor near the exhaust manifold has gone bad? Can anybody tell me what the nominal value should be? Should it not be constant? Again, this is the part where I'm still trying to learn things.
Here is a screenshot of the VCDS log:
https://pasteboard.co/JvtdYJb.jpg(full VCDS log file available here:
https://drive.google.com/file/d/1tuakMnkgzmtgDtysCY_yXhjs1u4b5cN8/view?usp=sharing)
Also, if you notice anything else unusual in there, please let me know. Thanks!