goldcrow

Hi guys,

Recently I noticed my E300 starting pinging after a relative borrowed the car and returned it with a tank full of 95 RON from a different station than my usual. Btw, manual states 95 RON is fine for this engine. Car has only done 28k kilometers since it's a garage queen.

At idle, there's no pinging whatsoever. Even revving it hard at standstill I can't make the engine ping. It's only heard in 3rd gear onwards at low rpm, 1000-1500rpm. At high speeds when doing an overtake, it can be heard too. Basically it pings when doing heavy acceleration from 3rd gear onwards.

I figured it must be poor quality fuel, so drove it sedately till my next fill-up. ​​​​​​Fast forward to two full tanks of 97 RON later, its much better but still appears when mashing the throttle.

Should I just keep filling it up with 97 RON til it finally disappears or should I start looking at other things, like spark plugs and coils? My local benz shop still hasn't replaced these as its on the 60k km/10yr service interval.

juanmor40

I have heard it on my E350 M276 occasionally, and I had the same thought about "I should have waited for the usual gas station".

I just let the tank go lower than usual, not too low to prevent the fuel pump from overheating, add a branded fuel injector cleaner, say Techron, and top it off. Then, take it for a good trip without the stop-and-go of city driving. An Italian tune-up of sorts depending on how hard you want to drive it.

If it goes away, just be watchful of the gas stations and be prepared for fuel pump filter maintenance in the near future. My car's filter is still original at 90K+ miles; however, last year traveling overseas I drove cars that need fuel filter replacement about twice a year depending on how often they are driven, basically dirt from gas stations

goldcrow

Wow, I did exactly what you just suggested on my second full tank. However, I only got it to a quarter tank, added the techron concentrate then filled it up. I've only used about a quarter of this second fill-up. As its only good for around 40liters and mine has the 80L tank, I'll probably add another techron bottle on my next fill.

I've been reading and watching about engine knocks and it doesn't really fit, almost all knocking engines can audibly be heard even on idle and revving up in Neutral. I just want to rule it out as that's a much bigger problem than I can manage right now.
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chassis

Which model do you have, E300 or E350? Which engine do you have? Please post a photo of the engine bay.

goldcrow

It's the facelifted W212 E300 with the M276 rated at 250+hp.

chassis

Thanks. E300 designation threw me.

juanmor40

https://en.wikipedia.org/wiki/Merced...E-Class_(W212)

OP is based in the Philippines

goldcrow

You got it. The local MB distributor brought in the detuned engine back when Euro2 was still the standard. Now I believe it's mostly Euro4 or 5 being sold in gas stations.