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Weird engine performance issue - Jim Cash help! (archive)

[ Follow Ups ] [ 5-series (E39) Message Board ] [ Msg. Board FAQ ]

Posted by BillP on July 09, 2000 at 16:17:28:

If this hadn't happened to me, I wouldn't have believed it, so I won't be bothered if none of you believe it.

My '00 540iA/sport just clicked over the 2K mileage mark and two rather dramatic occurences followed suit:

1. The engine/exhaust "growl" improved immensely when accelerating. I pay special attention to this because I was thinking of going with a third-part exhaust system to increase the sound but now think it is perfect. The windows/doors/sunroof are all closed (as before) and I still have an empty trunk so I can't find an external reason for this.

2. My fuel mileage shot up from 14-15mpg (many consecutive tanks at that level) to 19-20mpg (one tank). Other than *lowering* the pressure in one tire (see my post from yesterday), there was no significant changes that would account for this (type of driving, average speed, fuel source, octane grade, weather, locale/elevation, etc.)

So, here's my hypothesis - I'm looking for someone to confirm or deny: something in the 540's ECU is triggered when the car goes over the 2K mileage mark that affects the engine timing and/or fuel mixture with the benefit of "babying" the engine early in its life.


TIA,
Bill





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