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RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 14,332
You have to consider the driving conditions and the precision of the system itself. The WUR is located on top the engine and is influenced by the ambient temperatures. An extreme example of this is winter driving. On a sub-freezing day my engine will operate normally while idling or driving slowly, then after a burst of high speed it will idle hunt upon coming to a stop, which indicates and overly rich condition. Simply put, the WUR got so cold it knocked down the fuel pressure in response to the temperature. A stock engine would be much less prone to do this but you get the idea.
I see the same spikes in my graphs as you have. I am not certain exactly what phenomenon is being read by the O2 sensor at that time but I do know that if it is indeed real that it must not be harmful as I see it commonly on healthy engines such as my own that have been operating that way for decades.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 09-13-2010, 06:48 PM
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