Mega Users seabass07 Posted January 10, 2011 Mega Users Share Posted January 10, 2011 I've been keeping track of my learning views because I am going to use them to scale my closed loop maf scaling. They are not bad in the 40+ area...usually between -.3 and -1. From one day to the next, my 0-5.6 fuel trims went from +10 to -10. How is this possible? All I did was reset the ecu to clear the learned knock and it settled in at -10. I upped my maf scaling in that area by 5% because I made the adjustment when it was at +10. That made it go to -12. I know it is not really dangerous because everything looks very good above that range, but I am very confused as to the cause of this. I let the trims settle in for a while.LearningView_1-6-2011 11 34 15 AM.csvLearningView_1-7-2011 1 12 06 PM.csv Link to comment Share on other sites More sharing options...
Boostin1657615274 Posted January 10, 2011 Share Posted January 10, 2011 You can chase your proverbial tail all day long with MAF scaling but if the car is driving fine you don't need to worry about it. Have you ever checked fuel trims on a 100% unmodified random car like a Camry? They vary like that all the time. On the search for a new DD... Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted January 10, 2011 Author Mega Users Share Posted January 10, 2011 What confuses me is that I have kept track of this since october and even through many reflashes and resets, it has always been +10. Now all of the sudden it went to -10. I am was also getting a rougher idle than normal after the reset until it settled in. In one day, I did several learning views. It started out at 10, then went to 6, then 4, then I did a reset to isolate my knocking and it settled at -10. I'm going to tear apart the intake and make sure everything is sealed and there is nothing blocking airflow. Im not too worried since my 40+ is still good, just confused after seeing it so consistent for months. I'm not going to mess with maf scaling anymore until I figure this out though. Really the maf scaling was just me being anal and trying to get the number down to 0. I'm on the stock filter/intake. Link to comment Share on other sites More sharing options...
black318i Posted January 10, 2011 Share Posted January 10, 2011 A maxed on me when a vac line came off the FPR on the Mani side which I don't think is the case with your car, but easy enough to check. Also how is your intake filter? Link to comment Share on other sites More sharing options...
rtbrjason Posted January 11, 2011 Share Posted January 11, 2011 You'll never get the numbers to be 0. If you watch the actual correction happening when you drive, it will swing all over the place. You can get it close by making sure the maf is fairly well dialed in. Once you get the maf scaling close, you need to use the MRP compensation table to address areas of learning that happen at different levels of mrp. There is a huge variance at different pressures as seen in the attached pic of my rom. Once you get the mrp pretty close and you want to dial it in further, you can address the maf scaling IAT compensation table a bit to account for warm starts, and sitting at lights, and added air from extreme cold that further throw the trims off. I noticed on my car that though I had the scaling dialed in, at certain points on long highway drives my learning D would drop to -5% to -8% which is too much for my tuned fuel table. The MRP table fixes that and as you can see I pull as much as 6% out in the 0 mrp and 2800-3000 rpm area. I use this sheet to log/filter all my data and adjust maf/mrp as well as keep track of knock. http://www.romraider.com/forum/viewtopic.php?f=32&t=6313&p=60882 Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted January 11, 2011 Author Mega Users Share Posted January 11, 2011 Thanks for the help guys. The filter has about 8k miles on it. I shook it out, but looks good. I replaced it anyway yesterday to start fresh and I was already doing the oil. rtbrjason: I've been using that to log my knocking, but I never considered using it for anything else since everything is still stock except for the tune. I'll mess with it today and figure it out. My 40+ did go from -.03 to -2.8, but that is the most it has ever swung around. I'm not worried about that because my fueling is pretty rich from previously compensating for what turned out to be false knock. BTW, I'm messing with my maf scaling so I can lean things out a bit. I had dialed it back to 10.7 in the higher power areas due to knock at full boost. But I realized that the knock was caused by my engine/transmission mounts being worn and the transmission/engine bucking when taking off. Full boost is just where the 5eat likes to downshift to in sport. Link to comment Share on other sites More sharing options...
NSFW Posted January 12, 2011 Share Posted January 12, 2011 My idle fuel trim moves around quite a bit as well. I wouldn't be surprised if yours was back above zero if you check it next week. Or even tomorrow. Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted January 12, 2011 Author Mega Users Share Posted January 12, 2011 Thanks. That makes me feel better. Link to comment Share on other sites More sharing options...
Boostin1657615274 Posted January 13, 2011 Share Posted January 13, 2011 The part about the car briefly idling funny after a reflash is normal. Now assuming you don't have a knock problem, ask yourself this: If I didn't know even know what a fuel trim was, would I notice a problem right now? It's easy to be come a tuning hypochrondriac. The trims are designed to shift around. In the low load range you just have to make sure they aren't pegged in one directon and you don't have any driveability problems. On the search for a new DD... Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted January 13, 2011 Author Mega Users Share Posted January 13, 2011 The rough idle persisted for about a full tank...so Im going to blame the gas for that. Im over it now. I was just being anal. I wont start worrying until my 40+ goes up out of nowhere. As for knock, I just reduced my wastegate duty by 10% until I replace my engine and trans mounts. Im getting consistent shift knock and knock when starting from a stop. I know my engine is bucking because I hear it clank sometimes. I reduced my wastegate just incase Im wrong about the cause of the knock. Ive been chasing my tail over this for 2 weeks now. I reduced timing and eventually added fuel when it didn't go away. Increasing tip in enrichment didn't help either. Link to comment Share on other sites More sharing options...
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