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Title: Lean Burn VR6 Post by: wheelie on April 15, 2011, 01:15:46 PM Background: I (some punk kid) would like some better gas mileage out of his VR6 and was graced to stumble on this forum.
Goals: First test will be a target lambda during cruise of approximately 1.1. Following successful testing E85 will be tested when available locally to further push the lean burn to a lambda of approximately 1.2+ due to the increase of laminar flame speed upon enleanment using ethanol. I would also like to tune injection timing to aid in combustion stability (could be helpful at low load and rpm.) I have never tuned a stock ECU but managed to pull the hex and load it into WinOLS. I think the lambda maps are at 15008 and 151CC of size 14x14 each, but I have no idea if that is right. I haven't spent the intense time investment to decompile the bin. I uploaded my original bin yesterday and have failed to find any definition files for the ECU in question. A sanity check on these two locations from the ECU cracking pro's would be a great help! Thanks! Wheelie. Title: Re: Lean Burn VR6 Post by: Rick on April 15, 2011, 03:20:57 PM lambda maps won't help you here, the ECU will be running in closed loop during partial load, regardless of what you set the requested lambda too.
Title: Re: Lean Burn VR6 Post by: wheelie on April 15, 2011, 04:04:58 PM Sorry, I must be used to the Bosch Motorsport stuff being more straight forward and only having a single target lambda map. Somewhere there must be a map or value of the closed loop lambda's target. I was assuming it was a map after watching the target lambda dip under acceleration, maintaining closed loop with the short term and long term trims adjusting the actual lambda to meet it. The map I would like to change is the map determining these lambda targets in the first place.
Title: Re: Lean Burn VR6 Post by: Rick on April 16, 2011, 03:34:12 AM There is no way to tell the ECU to run a lambda target other than lambda 1 in normal conditions. There is no target lambda map for this condition, as the ECU is always trying to fuel lambda 1. There are other enrichment maps which will richen things up depending on the condition, e.g. WOT.
The sensor is a narrowband unit, it can ONLY work with a target lambda value of 1. The only way to do what you wish to achieve is to disable closed loop. Rick Title: Re: Lean Burn VR6 Post by: wheelie on April 16, 2011, 11:10:53 AM The sensor is a narrowband unit, it can ONLY work with a target lambda value of 1. The only way to do what you wish to achieve is to disable closed loop. My (flawed?) understanding is that the MKIV VR6 has a pre-cat wideband lambda sensor (Bosch lsu 4.2 or 4.9?) and a narrowband post-cat O2 sensor. I have a lot to learn about OEM engine control systems, but I would be very surprised if it didn't use the nice wideband it has access to. Title: Re: Lean Burn VR6 Post by: Rick on April 18, 2011, 01:10:07 PM I doubt it has wideband, it's too old, but you need to confirm.
Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 18, 2011, 02:18:54 PM I doubt it has wideband, it's too old, but you need to confirm. It has a wideband for sure. Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 18, 2011, 02:23:11 PM Background: I (some punk kid) would like some better gas mileage out of his VR6 and was graced to stumble on this forum. Goals: First test will be a target lambda during cruise of approximately 1.1. Following successful testing E85 will be tested when available locally to further push the lean burn to a lambda of approximately 1.2+ due to the increase of laminar flame speed upon enleanment using ethanol. I would also like to tune injection timing to aid in combustion stability (could be helpful at low load and rpm.) I have never tuned a stock ECU but managed to pull the hex and load it into WinOLS. I think the lambda maps are at 15008 (KFPU) and 151CC of size 14x14 each, but I have no idea if that is right. I haven't spent the intense time investment to decompile the bin. I uploaded my original bin yesterday and have failed to find any definition files for the ECU in question. A sanity check on these two locations from the ECU cracking pro's would be a great help! Thanks! Wheelie. IIRC The ecu normal lean limit is 1.05 so you have to change that first, then change your target lambda to leaner than 1. If you change the maps you mentioned above the ecu will still target 1 lambda. LAMFA = target lambda = 1B5F6 One thing you could look into is changing the O2 sensor voltage table and trick the ecu into thinking its richer than it is.????? Title: Re: Lean Burn VR6 Post by: Giannis on April 23, 2011, 12:09:59 PM what about the map for labda at partial load(kflf)? I am also interesting in some eco tuning. Unfortunaly the gas prizes in Greece go a lot higher than our salaries ::)
Title: Re: Lean Burn VR6 Post by: Rick on April 25, 2011, 03:13:14 PM you must disable closed loop first
Title: Re: Lean Burn VR6 Post by: Giannis on April 26, 2011, 03:06:18 AM Rick thank you for your anwer. Can we disable closed loop on certain load/rpm areas or we must disable it entirely. And do you know how to do it?
Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 26, 2011, 08:01:28 AM Rick thank you for your anwer. Can we disable closed loop on certain load/rpm areas or we must disable it intarelly.And do you now how to do it? You can unplug the oxygen sensor. Title: Re: Lean Burn VR6 Post by: Giannis on April 26, 2011, 08:15:52 AM I don't want to disable entirely the o2 sensors for 2 reasons. First i don't have any other means to log the AFR am not a proffesional tuner just a hobbyist i can't afford such equipment and second i don't want to disable the closed loop function entirely cause it could take years for me to fine tune the injectors to run in desired afr all the time.I would like if possible to deactivate it only in certain areas (cruising at low loads.) or better to make the ecu to working in leaner afr's in such conditions. I found some constant values regarding lambda i will test them and post the resaults.
Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 26, 2011, 08:18:50 AM what about the map for labda at partial load(kflf)? I am also interesting in some eco tuning. Unfortunaly the gas prizes in Greece go a lot higher than our salaries ::) I'm no expert so anyone PLEASE correct me if I'm wrong. KFLF would be the incorrect map to alter for what you are trying to achieve. KFLF is in the beginning part of a complex fueling algorithm. In the middle of this "algorithm" is a desired AFR/Target lambda->(LAMFA, KFLBTS..),<- Currently your ecu is trying to achieve a target lambda so if all you change is KFLF then the ECU will correct your changes to get back to this target lambda. Title: Re: Lean Burn VR6 Post by: Giannis on April 26, 2011, 09:27:52 AM Maybe you are right but i also changed LAMFA with no success i think that Rick knows more about the subject. The point is that there are some limiters somewhere that don't allow the lambda to drop below 1.05. I am trying to find those limiters and see what will happen.
Title: Re: Lean Burn VR6 Post by: Rick on April 26, 2011, 12:42:30 PM Changing LAMFA won't work.
Firstly, you need to disable closed loop in the RPM areas you wish to run leaner. You need the map RLRUN, lower load threshold for closed loop operation. This is an 8x1 map of rpm against load. Closed loop will be disabled below this load. Leave closed loop alone for idle rpm, then from say 1300rpm until 4000 rpm you can disable closed loop by entering a high load value in these bins. Once you have done this, use KFLF to tune to the AFR you require in these load/rpm areas. Rick Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 26, 2011, 01:46:20 PM Changing LAMFA won't work. Firstly, you need to disable closed loop in the RPM areas you wish to run leaner. You need the map RLRUN, lower load threshold for closed loop operation. This is an 8x1 map of rpm against load. Closed loop will be disabled below this load. Leave closed loop alone for idle rpm, then from say 1300rpm until 4000 rpm you can disable closed loop by entering a high load value in these bins. Once you have done this, use KFLF to tune to the AFR you require in these load/rpm areas. Rick Is there no way to set a leaner target for closed loop operation? Its RLLRUN Title: Re: Lean Burn VR6 Post by: Rick on April 26, 2011, 02:14:03 PM On narrowband - no. On wideband - maybe? There probably is but I've never worked with one.
Rick Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 26, 2011, 02:27:40 PM On narrowband - no. On wideband - maybe? There probably is but I've never worked with one. Rick This might be a real easy solution= LALIUS It would need to be perfected with an external wide band. Change the sensor calibration to a richer lambda than it really is. Done Title: Re: Lean Burn VR6 Post by: AudiA4_20T on April 26, 2011, 02:48:06 PM question. This may sound dumb to you tuners but the closed loop/open loop thing confuses me. Is closed loop a condition that relies on pre-determined maps in the ECU and sticks to it, while open loop is constantly taking in data from the sensors and adjusting accordingly? That is my interpretation of it. I know that in certain circumstances though like a busted CTS or something will keep the car in closed loop, is this true?
Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 26, 2011, 02:59:45 PM question. This may sound dumb to you tuners but the closed loop/open loop thing confuses me. Is closed loop a condition that relies on pre-determined maps in the ECU and sticks to it, while open loop is constantly taking in data from the sensors and adjusting accordingly? That is my interpretation of it. I know that in certain circumstances though like a busted CTS or something will keep the car in closed loop, is this true? I think you have it backwards. Open loop is when the ecu is using internal maps to calculate its outputs. Closed loop is when the ecu uses the internal maps + external sensors to calculate its outputs. Title: Re: Lean Burn VR6 Post by: AudiA4_20T on April 26, 2011, 05:33:16 PM question. This may sound dumb to you tuners but the closed loop/open loop thing confuses me. Is closed loop a condition that relies on pre-determined maps in the ECU and sticks to it, while open loop is constantly taking in data from the sensors and adjusting accordingly? That is my interpretation of it. I know that in certain circumstances though like a busted CTS or something will keep the car in closed loop, is this true? I think you have it backwards. Open loop is when the ecu is using internal maps to calculate its outputs. Closed loop is when the ecu uses the internal maps + external sensors to calculate its outputs. Got it. And I suppose in closed loop there are a bunch of maps that the ECU "refers" to based on certain inputs? Trying to understand more how the ME.7 works Title: Re: Lean Burn VR6 Post by: Rick on April 27, 2011, 12:32:56 PM The maps used are the same for open loop and closed loop. The difference is in closed loop the ECU will correct anytime the target lamda doesn't equal the actual lambda.
LALIUS would be no good unless it was at least dependant on load or rpm or both. Rick Title: Re: Lean Burn VR6 Post by: Giannis on April 27, 2011, 12:33:21 PM Thank you all for the great answers. My friend 240sx i would prefer not to change the calibration of the LAMBDA sensor because as i told you before i have no other way to mesure the REAL AFR.
@Rick i think your way is more right. How much sould i raise the values of the map? Stock values are 6.000 in all rpm range. I'm thinking that from 1200rpm to 4000rpm should be ok. @ A4_20T the big difference between open and closed loop is that, in an open loop system you set some target values for something (eg target lambda) and the output is calculated by various sensor data and other formulas but YOU HAVE NO MEANS TO CORRECT IT to the desired level in case that something goes wrong with your calculations or one sensor. In closed loop you have everything that i said before PLUS A FEEDBACK OPTION in the final output so that it can be corrected again to match the desired output. Sorry but my english don't help me a lot. I am no tuner just an amateur and this is what i have understood so far. Forums literature and other people with much more knowledge than me helped me a lot. There are many of them in here. :D Title: Re: Lean Burn VR6 Post by: Rick on April 27, 2011, 12:38:16 PM I find a good load threshold is around 60-70.
Title: Re: Lean Burn VR6 Post by: Giannis on April 27, 2011, 12:39:48 PM Thank you very much Rick i will test them and post the results.
Title: Re: Lean Burn VR6 Post by: 240sxpooter on April 27, 2011, 12:48:49 PM Thank you all for the great answers. My friend 240sx i would prefer not to change the calibration of the LAMBDA sensor because as i told you before i have no other way to measure the REAL AFR.The sensor would still work just fine the scale could just be shifted and you could use the ecu to target the leaner lambda @Rick i think your way is more right. How much sould i raise the values of the map? Stock values are 6.000 in all rpm range. I'm thinking that from 1200rpm to 4000rpm should be ok. @ A4_20T the big difference between open and closed loop is that, in an open loop system you set some target values for something (eg target lambda) and the output is calculated by various sensor data and other formulas but YOU HAVE NO MEANS TO CORRECT IT to the desired level in case that something goes wrong with your calculations or one sensor. In closed loop you have everything that i said before PLUS A FEEDBACK OPTION in the final output so that it can be corrected again to match the desired output. Sorry but my english don't help me a lot. I am no tuner just an amateur and this is what i have understood so far. Forums literature and other people with much more knowledge than me helped me a lot. There are many of them in here. :D RLLRUN = 160A4 in a 018M ecu Title: Re: Lean Burn VR6 Post by: Giannis on April 28, 2011, 05:23:04 AM Great news guys!! closed loop seems to be inactive now. I am not getting any lambda addaptation values in vagcom channel 33 now, although i am running rich. Now i supose i much callibrate FKKVS to reach the desired AFR. An other happy sideffect of turning off closed loop is that by turning off ECU addaptation ability, you can calibrate your injectors much more easily because you can see the real AFR from the injection map applied. I will keep you informed thank you again.
Title: Re: Lean Burn VR6 Post by: Rick on April 28, 2011, 01:52:24 PM Cool, glad it's working for you :)
Title: Re: Lean Burn VR6 Post by: Giannis on May 01, 2011, 01:53:27 AM Rick i am still running rich. Witch maps should i use to fine tune my injectors? I also noticed that by tuning KFLASWLR seems the requested lambda changes for 1.00 to whatever you set it to. Have you tried to use this map to reach lambda 1.10 without dissabling the closed loop?
Title: Re: Lean Burn VR6 Post by: Rick on May 03, 2011, 12:38:36 PM How do you mean you are running rich? What map have you changed, and do you have a standalone wideband?
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