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Re: Used Oil Analysis - High Nitration and Fuel Dilution Posted by Mark in Marine [Email] (#1837) [Profile/Gallery] (more from Mark in Marine) on Thu, 5 Dec 2019 20:57:34
In Reply to: Used Oil Analysis - High Nitration and Fuel Dilution, Roger (NAWC), Thu, 5 Dec 2019 05:32:56 Members do not see ads below this line. - Help Keep This Site Online - Signup
I doubt I'm the guru that you need, but I have a few observations.
1) At 127F the engine is definitely not at operating temperature, so I would treat data as incomplete. I suggest doing data logging from cold start all the way through warm-up (four to six minutes of log most likely). Short term fuel trim is high, but if the car is not yet warm, you don't know where it might have gone once warmed up.
2) Is your oil analysis just a single data point? I haven't been a frequent user of used oil analyses, but after reading your thread, I will look up the test methods. What oil are you using? Any chance you saved back a little oil from the same jug as your last used oil sample? If so, you could run that as a control sample to compare before/after with your used oil. As a chemist I'm cautious about test results without a good baseline.
3) New MAF may be good to try, but before you install it, remeasure the old MAF signal at idle with the engine fully warm. Maybe one of the mechanics can comment on a spec value for a good MAF on a good engine. And of course idle speed and individual engine differences will matter. I have not seen a spec, but I have not looked hard.
I assume your compression test is good and you are not observing pressure in the crankcase at idle? Mobil's PDF on causes of nitration in lubricating oil suggests that blow-by and leaking turbo seals will contribute to this. But the question might be "will a 5K oil change interval handle this?" - if they do, maybe you have no worries . . .
Hope these thoughts help some.
Mark in Marine
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