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  #1  
Old 01-17-2015, 01:29 PM
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Oil life algorithm still buggy

My 2014 EcoDiesel is flashed up to the "early September 2014" firmware release level. However, I have discovered that the "remaining oil life" algorithm is still in need of refactoring.

For example, over the course of driving less than 20 miles in town today the remaining life dropped from 8% to 6%, which would correlate linearly to an oil change interval of ~1,000 miles rather than 10,000 miles. And, no, I wasn't drag racing or towing today... just driving 50/50 highway/surface streets.

I know from the UOA TBN numbers there is still life left in the oil even if it "magically" drops from 6% to 0% today; however, I like to keep photographic records to document my oil changes and showing that the remaining oil life indication is above 0%.

It doesn't seem unreasonable to expect a predictable oil lifespan algorithm, or at the very least, one that doesn't have precipitous drops.

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Old 01-17-2015, 10:33 PM
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Meh. Dropped another 1% in 20 miles this afternoon... down to 5% remaining. At this rate I won't have time for a filter to be delivered before the calculation hits 0%.

Irked.
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Old 01-18-2015, 10:49 AM
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Mine is calculating perfectly. However I've never went below 20% remaining.
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Old 01-18-2015, 11:09 AM
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Re: Oil life algorithm still buggy

So how many total miles were on the oil when it reached 6%? I wouldn't expect the mileage to be linear with the percentage. The algorithm deals with engine temperature and run time between stops.
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Old 01-18-2015, 01:32 PM
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Originally Posted by Traveler0980 View Post
So how many total miles were on the oil when it reached 6%? I wouldn't expect the mileage to be linear with the percentage. The algorithm deals with engine temperature and run time between stops.
9,200 miles on this oil.

Given that the algorithm is created by Chrysler rather than being based on some impossible realtime oil quality sensing, there's no reason that the algorithm has to go completely nonlinear at the end like this.

What's the point of a numeric value like this if one can't use it to plan? As you can see, the algorithm has essentially followed the linear model for the first 9/10 of the expected lifespan range or there's no way it would have gotten this far.

There's an order of magnitude increased decay here. I was planning to change it at 5%, but it dropped from 8% in 40 miles yesterday.

Before they "fixed" the algorithm last year, a very similar nonlinear decay rate existed except it kicked in around 60% remaining life: more or less linear to that point, then the decay rate accelerated until towards the end I saw it drop by 1-2% in a matter of 5 miles.
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Old 01-18-2015, 10:38 PM
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Re: Oil life algorithm still buggy

Mine is calculating perfectly....
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Old 01-19-2015, 01:27 AM
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Originally Posted by fun2drive View Post
Mine is calculating perfectly....
So on the current firmware you've driven the oil lifespan calc below 10% found it to continue to decrease more or less linearly down past 5% remaining?

As I mentioned, the first 90% of life was essentially linear... 92% in 9,200 miles, followed by increasingly rapid decay such that the remaining 8% is likely to decay in under 150 miles.
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Old 01-19-2015, 09:33 PM
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Re: Oil life algorithm still buggy

Quote:
Originally Posted by Roadkill View Post
My 2014 EcoDiesel is flashed up to the "early September 2014" firmware release level. However, I have discovered that the "remaining oil life" algorithm is still in need of refactoring.

For example, over the course of driving less than 20 miles in town today the remaining life dropped from 8% to 6%, which would correlate linearly to an oil change interval of ~1,000 miles rather than 10,000 miles. And, no, I wasn't drag racing or towing today... just driving 50/50 highway/surface streets.

I know from the UOA TBN numbers there is still life left in the oil even if it "magically" drops from 6% to 0% today; however, I like to keep photographic records to document my oil changes and showing that the remaining oil life indication is above 0%.

It doesn't seem unreasonable to expect a predictable oil lifespan algorithm, or at the very least, one that doesn't have precipitous drops.
Mine did this right after they flashed it and changed the oil back in September - for first 250-300 miles oil life dropped 8%, or equivalent of 800 miles driven. it is still off by 5-7%.
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