fahr_side Posted May 15, 2013 Share Posted May 15, 2013 What are proper fuel trim values for a,b,c,d. Trying to find some kind of reference to see how out of wack my fuel trims are. They should all be fairly even, and slightly negative values are preferred. I like to see numbers between 0 and -5.00, but that's me. Note that not every stock ROM uses the same load values in these ranges, and certainly not every tuner sets them up the same way. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
Tehnation Posted May 15, 2013 Share Posted May 15, 2013 My a is fucked, started at 15 and is slowly going down the more I drive it, last time it reached +9.9 before I reset it to get rid of the knock. My b is + .90, c varies from +2 to +5, and d varies from -1.5 to -.10. Ive sealed and ziptied and changed most gaskets to make sure I have no leaks, idles fine drives fine. Changed my spark plugs and thats what made my a value actually start to go down. So I'm thinking fuel injectors are the real culprit. Link to comment Share on other sites More sharing options...
iNVAR Posted May 15, 2013 Share Posted May 15, 2013 Have you cleaned your MAF sensor? The MAF sensor are the thin wires up the tube when you remove the whole thing. The little brown thing is a temperature sensor. It still sounds like you have an intake leak somewhere. Link to comment Share on other sites More sharing options...
Tehnation Posted May 15, 2013 Share Posted May 15, 2013 Lol , I already went through all that, new o2 sensors, maf, tgv gaskets, turbo inlet hose, zip tied hoses, uppipe gaskets. There is NO leak lol. My thread so far. http://legacygt.com/forums/showthread.php/high-idle-fuel-trim-204259.html Link to comment Share on other sites More sharing options...
Tehnation Posted May 17, 2013 Share Posted May 17, 2013 Latest lv http://legacygt.com/forums/picture.php?albumid=1565&pictureid=8388 Link to comment Share on other sites More sharing options...
iNVAR Posted May 18, 2013 Share Posted May 18, 2013 Did you disconnect your rear O2 or something? Link to comment Share on other sites More sharing options...
Tehnation Posted May 18, 2013 Share Posted May 18, 2013 Its a new oem one, but the engine code doent seem right normally I get a catalytic converter code. Going to put in the old one to see what happens. Link to comment Share on other sites More sharing options...
Tehnation Posted May 27, 2013 Share Posted May 27, 2013 Bad injectors were the problem. Link to comment Share on other sites More sharing options...
UTwrestler22 Posted May 28, 2013 Share Posted May 28, 2013 I have kind of a complex question that I searched little for but the place that dyno tunes near me requires an ap and they say open source on a dyno isn't nearly as good as Cobb ap plus dyno. Useless basically. Should I find a different place to get dyno tuned? I don't really feel like paying 1100 dollars for a tune Link to comment Share on other sites More sharing options...
iNVAR Posted May 28, 2013 Share Posted May 28, 2013 The AP allows a tuner to make changes to things and immediately apply them while the laptop is hooked up to the car. OS doesn't allow that. You have to log, make adjustments, flash, relog, adjust, flash, etc. Link to comment Share on other sites More sharing options...
UTwrestler22 Posted May 28, 2013 Share Posted May 28, 2013 That makes sense. I hate to get into numbers again, but will an ap give you better numbers from a dyno tune? Link to comment Share on other sites More sharing options...
iNVAR Posted May 28, 2013 Share Posted May 28, 2013 I think the answer to that is: It depends, on the tuner. If the tuner is good and advises you to get an AP, then an AP is probably better. Link to comment Share on other sites More sharing options...
UTwrestler22 Posted May 30, 2013 Share Posted May 30, 2013 Yeah they're cobb protuners and won't even tune without an ap Link to comment Share on other sites More sharing options...
Tehnation Posted May 30, 2013 Share Posted May 30, 2013 Pros and cons to everything , opensource is cheaper and only requires laptop and tactrix/vagcom cable, but your limited to how you can do things. AP is more expensive but you get what you pay for and is a bit more robust, such as on the fly tuning. But in the end I believe you will get the same or similar results if you had two tuners both equal in skill and one is using ap and the other os. If cost is a factor I would shop around for an os tuner whos somewhat close by, might have to drive a couple hours but the ride home would be a blast! Or consider an etune for 150-200 bucks depending on your mods. Link to comment Share on other sites More sharing options...
Tehnation Posted May 30, 2013 Share Posted May 30, 2013 And from what I have gathered a lot of tuners dont like OS tuning because their tunes can be copied by others and basically their hard work can be given away for free. A lot of them stick to AP because you cant copy the tune therefore ensuring that, that tuner can put food on the table for his family! You have options! Link to comment Share on other sites More sharing options...
chimera Posted May 31, 2013 Share Posted May 31, 2013 And from what I have gathered a lot of tuners dont like OS tuning because their tunes can be copied by others and basically their hard work can be given away for free. A lot of them stick to AP because you cant copy the tune therefore ensuring that, that tuner can put food on the table for his family! You have options! Fair point. Personally I'm paying for a service, so would never have the intention (let alone know-how!) to rip off their tune. But, I thought the tune varied from one car to another because even the same models/years, are still all slightly different? Link to comment Share on other sites More sharing options...
fahr_side Posted May 31, 2013 Share Posted May 31, 2013 And from what I have gathered a lot of tuners dont like OS tuning because their tunes can be copied by others and basically their hard work can be given away for free. A lot of them stick to AP because you cant copy the tune therefore ensuring that, that tuner can put food on the table for his family! You have options! I love OS because I can charge the customer only for my time, instead of that plus a license fee to kick upwards or some otherwise useless bit of hardware the owner doesn't want or care about. It is possible and I do protect my work from the usual morons who'd copy a custom tune and try to sell it as a basemap or as their own work. It's done by changing the ROMs internal ID and that ROM can then only be edited with a custom definition. It won't fool someone who knows what they're doing but the average scam artist doesn't. Another tool in the works is to makes the ROMs write-only. It won't be possible to download or edit the ROMs, only overwrite them. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
iNVAR Posted May 31, 2013 Share Posted May 31, 2013 Wouldn't that be called a WOM then? Link to comment Share on other sites More sharing options...
chimera Posted May 31, 2013 Share Posted May 31, 2013 Haha! There are enough acronyms on this site don't invent a new one! ROM is read only, the ECU must really have an EPROM (has to be if can be written too/flashed) Link to comment Share on other sites More sharing options...
fahr_side Posted May 31, 2013 Share Posted May 31, 2013 ROM is read only, the ECU must really have an EPROM (has to be if can be written too/flashed) Correct. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
UTwrestler22 Posted May 31, 2013 Share Posted May 31, 2013 Wow. Thanks for all the info Link to comment Share on other sites More sharing options...
Tehnation Posted June 7, 2013 Share Posted June 7, 2013 Any input, trying to figure this out. Or is this normal? I'm in the middle of stage 2 tuning. http://legacygt.com/forums/picture.php?albumid=1565&pictureid=8495 Link to comment Share on other sites More sharing options...
iNVAR Posted June 7, 2013 Share Posted June 7, 2013 Figure what out? Your LV is perfectly clean and your AF Trims look spot on. IAM is 1. That is a very healthy LV. Link to comment Share on other sites More sharing options...
Tehnation Posted June 7, 2013 Share Posted June 7, 2013 Thanks a bunch for the input! Just wanted to be sure I was going in right direction. Some people say it should be within +-1 others +-5, your comment made me feel alot better, I thought I would have to bust out the checkbook for more damn parts. But this negative positive stuff is confusing, - is rich and + is lean? These hoses and leaks are no damn joke, ive been trying to get stage 2 for about 2 months now. Link to comment Share on other sites More sharing options...
iNVAR Posted June 7, 2013 Share Posted June 7, 2013 +/-1 IMHO is a bit too strict. +/-5 seems reasonable. But honestly, it could probably be +/-10 even in the first 3 and it'd be fine. Trim D is the one that can be a bit concerning. A negative (red) number means your ECU is pulling fuel because it feels you have too much. Therefore, a negative number means you were/are running rich and the ECU is trying to lean it out. A positive (green) number means your ECU is adding fuel because it feels you are too lean. So it does the opposite. The interesting/important part is Trim D, which is applied (but not learned) in Open Loop, which is where WOT takes place. Link to comment Share on other sites More sharing options...
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