[sleepermax]

I just spoke with a service advisor regarding this. Just as the engine starts up, I can hear loud pinging/knocking for a sec or so. It's exactly like detonation, and is very unsettling.

The SA advised me to run 89 octane at least during break-in. We have 87, 89 and 93 here in Texas - no 91. He said all their E90's do this, especially in the morning. Something about the sulfur content in US fuel affecting the air fuel mixture at start-up and E90's not being exactly calibrated for it. Said they had tried all sorts of software fixes to no avail. They had a BMW Engineer come down to the dealership, who also happens to drive an E90. He advised them to use 89 Octane. SA said that even the BMW engineer is using 89 octane at the moment.

Anyone experince this or have additional insight? Not very happy having to use a lower grade fuel and compromise some of the performance I paid good money for in the first place. Although, obviously the alternative of potential engine damage from the pinging is something I want to avoid.

I think once this tankful of 93 is down to about half I'm topping it of with 89. This should give me a full tank of 91 - we'll see if this fixes the issue....

[Bimmerista]

It's the flux capacitor.


In Canada we have 91 octane-I have not experienced this problem.

[Hunter399]

I use 93 down in Houston and have no problems

[RPM90]

Originally Posted by sleepermax

I just spoke with a service advisor regarding this. Just as the engine starts up, I can hear loud pinging/knocking for a sec or so. It's exactly like detonation, and is very unsettling.

The SA advised me to run 89 octane at least during break-in. We have 87, 89 and 93 here in Texas - no 91. He said all their E90's do this, especially in the morning. Something about the sulfur content in US fuel affecting the air fuel mixture at start-up and E90's not being exactly calibrated for it. Said they had tried all sorts of software fixes to no avail. They had a BMW Engineer come down to the dealership, who also happens to drive an E90. He advised them to use 89 Octane. SA said that even the BMW engineer is using 89 octane at the moment.

Anyone experince this or have additional insight? Not very happy having to use a lower grade fuel and compromise some of the performance I paid good money for in the first place. Although, obviously the alternative of potential engine damage from the pinging is something I want to avoid.

I think once this tankful of 93 is down to about half I'm topping it of with 89. This should give me a full tank of 91 - we'll see if this fixes the issue....

Well now, that makes no sense.
If what you are hearing is indeed "knock", then lower octane will not fix the problem but can make it worse.
Higher rated octane fuel is LESS susceptible to knock, not lower octane fuel. It seems counter to what makes sense. However, maybe it's not knock.

Not only that, this whole "sulphur" thing used to be a much bigger concern. By this summer all US fuels have to have a lower sulphur content. The point, however, is that most fuel refineries have been using the lower sulpher formulations for a while now, so the sulphur thing seems an easy finger point, but doesn't make sense.

I would suggest trying a different name brand fuel.
Contrary to much popular belief the bigger brand fuel DO use their own formulations. No name gas stations and some not so big "name" brands, like Speedway, buy their fuel from the big refineries
Try an Amoco/BP premium or Shell premium and see if that helps first. Going with a lower octane fuel means more change of detonation/knock, and if it does occur the engine will retard timing and your engine will produce less than the power you paid for.

If this is true BMW has some explaining to do and not blame US fuel.
BMW before the E90 managed just fine with US fuel that had even more sulfur/sulphur than they do now.

What's up?

T

[shragon]

91 in california. no problems.

[David328M-Sport]

I use 98 RON Shell Optimax- no problems. The perfect fuel for my car.

[sleepermax]

Good points.

RPM90, I use Chevron. Although, one can still get pinging even with higher octane if the load is too much, or the timing is off, or ambient temperature is extremely hot ect ect. But you're absolutely right - lower octane should make the issue worse! When I start it up, it almost sounds like the timing off for a split second right at start-up, causing the pinging, and then it runs fine. Almost like the ignition signal is sent at the wrong point in the compression cycle. It's a very unpleasant sound, or rather it's extremely unpleasant knowing what is potentially happening within the cylinder walls!