thx for the update. I'm changing mine out this wknd.
Just in case it helps, here's what I've done in an effort chase down the pinging:
- O2 Sensor
- Fuel Filter
- Fuel Pressure test
- ECU water temp sensor (I think this may have helped a little, but its still cold out)
- 1 step cooler Spark Plug
- Chevron Premium fuel (so far, this has helped the most) - Shell makes it worse
- ECU reset
- Borescoped the Cylinders (all very clean)
- Drove with BMW Diagnostic Software running. Knock sensors are working fine. Timing is changing as needed
- Removed and examined MAF sensor. Couldn't be cleaner
- Vacuum leak smoke test
At this point, the last thing I'm changing is air temp sensor and rebuilding the vanos. From there, I'm left with the only option but to change the knock sensors just in case and then do an injector spray pattern test. I doubt its any of those.
If the problem still exists, it pretty much has to be late 1990s California change of fuel requirements that mid 1990s high performance cars aren't calibrated for.
My car only does it up a very steep hill at low speed. Other than that, engine is fantastic.
Will post an update.