My m50 is pinging. Running out of ideas.

[THEhomelessONE]

I'm getting OBD codes for nonexistent problems
Really want to know what's causing your ping problem, good luck m9.

[wakdog]

Im having problems with my S50 pinging recently - only happens for me at partial throttle as you go past ~4100rpm and only does it for 100-200rpm... Ive replaced my o2 sensor, tried a new MAF, changed fuel pressure reg, injectors are brand new 6k miles ago. I even tried another tune for my setup (24lb injectors + euro MAF) and it still did it :(

My car does make a fair bit of marbles in can noise as you decel - i know the vanos is on the way out but still not sure if this is the issue...

[Dj Buttchug]

This is a long ass thread with several issues that could all cause the problem. Reporting now after I tore my engine down and did a complete top end rebuild this is what I have found.

First, my engine is 200k plus and was not taken care of very well by previous owners. Likely a combo of shitty gas, worn plugs and oil change intervals that were never done on time caused my combustion chamber to look like this.




As you can see the carbon buildup is pretty bad. I dont have any pics of the valves or head but just imagine about the same amount of buildup on the valve heads and the surrounding area. Basically the whole combustion chamber was caked with it.


I posted in my e34 thread but im convinced the reason for detonation was carbon buildup. It made my car sluggish and it had no balls up top. At first I thought it was normal because m50 is just m50 and its slow as shit anyways but now after a fresh top end its a whole new engine. Its still slow but it totally rips. Much more top end pull, just better all around. I cannot get the engine to detonate or ping under any load, at any speed.


For those that still have issues you may want to stop throwing parts at your engine, pull a spark plug and take a peek down inside to see how bad it really is. Maybe get a piston on TDC and scrape the top with a screwdriver to see how deep the buildup is. I donno.

[Wishno87]

Thanks for the update. I have not resolved my pinging yet at this point. Did you see any physical damage that could have been from the detonation? I'm about to swap mine with an aluminum m52 soon but the GFs e34 still has the issue.

[Dj Buttchug]

Thanks for the update. I have not resolved my pinging yet at this point. Did you see any physical damage that could have been from the detonation? I'm about to swap mine with an aluminum m52 soon but the GFs e34 still has the issue.

no damage to the head or pistons but my valves were pretty shot. Some where burning in small areas and there was tiny chips.