E-Class (W210) 1995-2002: E 200, E 220D, E 240, E 290TD, E 300TD, E 200, E 240, E 280, E 320, E 420, E 430 (Wagon, Touring, 4Matic)

Oxygen Sensor Replacement

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Old 01-08-2009, 05:55 PM
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1991 SC Miata, 1999 W210 Estate Wagon
Oxygen Sensor Replacement

So these cars of ours have FOUR O2 sensors whose recommended change interval is 100K miles. Well, what's the harm of changing just the pre-cat sensors (aside from a false code due to greater delta readings from pre to post-cat sensors indicating bad cats)?
Old 01-09-2009, 12:06 PM
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1997 s320, 1997 e320
i think only the pre-cat o2 sensors have a 100k miles interval. and if i'm not wrong there are 3 in a v6 and only 2 in a i6. they are not cheap so i wouldn';t change them unless they are causing problems like an error code or bad gas mileage. if it isn't broke, don't fix it.

Last edited by tirona; 01-09-2009 at 12:08 PM.
Old 01-09-2009, 02:20 PM
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1991 SC Miata, 1999 W210 Estate Wagon
Bad gas mileage...

I can also smell a richer exhaust condition... black soot residue on the pipe is also a sign.
Old 01-09-2009, 03:07 PM
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things with and without wheels
Maf sensor can cause that too
Old 01-09-2009, 06:12 PM
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1991 SC Miata, 1999 W210 Estate Wagon
Oh, I've done the MAF already (last month, for CEL 0170 and 0173). Matter of fact, I think my original MAF is still good.
Old 01-09-2009, 06:45 PM
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300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
M112 and M 113 4 sensors

at 100k they are lazy.Renew the 2 precats if on a budget since they are the ones that oscillate the a/f ratio.The post cats are along for the ride and monitor cat function at a base line.Best performance and mpg will always be achieved with all 4 renewed.You can pick up the universal splice in ones with the new connection system for about half the cost.

ohlord

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