Ahoy, Skinnywater. What would happen to my ML if

I used 87 or 89 octane fuel?<br /><br />I have religiously fed her only 91+, but for $.20 a gallon less the idea that the ECU would adjust timing to compensate is attractive.<br /><br />In case you forgot: 1999 ML430, Stillen cat-back duals and aftermarket cone air intake. 81,000 miles.<br /><br />Thanks for your great advice.

Re: Ahoy, Skinnywater. What would happen to my ML if

Hello JB,<br />The ME control unit will adjust and react accordingly. Pre-detonation is non-existant with your motor because the configuration of your knock sensors and the ME2.1 system is a fast reacting system. <br />Your M113 engine is capable of sequential spark timing even between a single cylinders pair of spark plugs.<br /><br />So, one might think this would be a non-issue.<br />However, through my own experience on my wifes C class Kompressor and what I've noticed recently.<br />Our ME systems are adaptive. As our systems adapt to a substandard requirement there are other drivability concerns that are likely to be experienced.<br />This can be as mild as extended crank times to severe power loss.<br /><br />I'm sorry JB but real problems are surfacing recently because of the practice.<br />And in the case of my wifes C class I had a very hard time resetting the adaptation process of the ME control unit and it was a close call to a hefty replacement cost.<br />As much as gas prices in general pains me the extra $4-5 on a fill up is worth the satisfaction of owning a Benz.

Re: Ahoy, Skinnywater. What would happen to my ML if

Thought that might be the case. <br /><br />Thanks.