wheelie
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« on: April 15, 2011, 01:15:46 PM »
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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.
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Rick
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« Reply #1 on: April 15, 2011, 03:20:57 PM »
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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.
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wheelie
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« Reply #2 on: April 15, 2011, 04:04:58 PM »
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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.
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Rick
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« Reply #3 on: April 16, 2011, 03:34:12 AM »
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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
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wheelie
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« Reply #4 on: April 16, 2011, 11:10:53 AM »
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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. |
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Rick
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« Reply #5 on: April 18, 2011, 01:10:07 PM »
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I doubt it has wideband, it's too old, but you need to confirm.
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240sxpooter
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« Reply #6 on: April 18, 2011, 02:18:54 PM »
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I doubt it has wideband, it's too old, but you need to confirm.
It has a wideband for sure. |
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240sxpooter
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« Reply #7 on: April 18, 2011, 02:23:11 PM »
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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.  ?? |
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Giannis
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« Reply #8 on: April 23, 2011, 12:09:59 PM »
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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  |
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Rick
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« Reply #9 on: April 25, 2011, 03:13:14 PM »
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you must disable closed loop first
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Giannis
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« Reply #10 on: April 26, 2011, 03:06:18 AM »
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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?
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« Last Edit: April 26, 2011, 02:14:58 PM by Tony@NefMoto »
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240sxpooter
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« Reply #11 on: April 26, 2011, 08:01:28 AM »
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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. |
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Giannis
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« Reply #12 on: April 26, 2011, 08:15:52 AM »
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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.
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240sxpooter
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« Reply #13 on: April 26, 2011, 08:18:50 AM »
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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. |
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Giannis
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« Reply #14 on: April 26, 2011, 09:27:52 AM »
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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.
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