I mistakenly put 87 octne fuel in my tank for my BMW 325ci - I usually put 93 octane in it. Will this damage my engine - the tank was .25 full before I put in the lower octane gas.
No worries. It will do no harm.
David is right 1 tank shouldn't be a problem but if you are worried just put in some good octane booster.
no harm done - just don't make a habit of it or your engine will start pinging....
Your engine will start pinging as soon as the high octane in the lines is burned off, which won't be long. You will also find that the computer retards the timing to stop this, and the timing will retard so far that the car will barely run, will have little power and will burn gas like a road warrior. Add octane boost now, and then at the 3/4 tank mark, top up with the super-high, 94 octane, or what ever the highest is you can get. Do that for a couple of times, and then go back to your normal grade of fuel. At the price of a replacement engine, it is better to take no chances on causing damage.
Cheap fuel wont hurt it at all poor performance is all and crappy mileage
All that say poor performance or poor mpg if you use a lower grade gas are incorrect. There has been thousands of test proven that higher octane is a gimmick and only required if you're going to the race track.
MDX, tell that to my Cadillac, I've tried running both regular and premium fuel in it and there is a 3 mpg drop in mileage and you really notice the drop in power especially in city driving, so I'm sticking with the good stuff in it. Now my Yukon doesn't seem to matter also I've ran both fuels in it and there is no change in mileage or power, even though it is a bigger engine it just does not require higher octane to achieve its maximum output. So there is a differance in fuels and a differance in engines that make fuel requirements stated in the owners manuals. If you follow those guidelines then there won't be any concerns with pre ignition problems or loss of power. And this thread is over 3 years old.
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