Lean-out issue around 3000rpm
Ik I talked to you about this issue already but am wondering if anyone else has played around with this anymore and found a better solution? I just picked up a taxtric cable so things are much more clear to me on whats going on.
I started playing with an accel table Golden provided and it seemed to make a small change on my car during initial tip-in. It's too soon to be sure as I need to use some much more aggressive numbers to determine if I was just hopeful or it in fact works properly.
However after looking at my logs I really think the Open Loop crossover is more of the ticket here.
On my car which is still a stock turbo I can easily high mid 130 load numbers which is positive pressure very early in the rpm range. In these ranges the Open Loop setting is "140". This factory setting obviously works until we tune the cars... MIVEC for instance would make us spool faster and hit higher load areas sooner requiring a change in more than just the standard fuel map.
I saw somewhere mentioned by mrfred I believe (maybe this thread) that the ECU when in closed loop targets 14.7 afr no matter what the fuel map says. If this is in fact true, the extreme lean conditions would be apparent when hitting positive boost areas quickly with no time for the ecu to compensate and by the time it could you've crossed the open loop crossover point anyway and are now running off the fuel map. Someone that has read the code would need to confirm this...
My opinion is if that is the case lowering the crossover point makes complete sense and why it helped scheides...
However after looking at my logs I really think the Open Loop crossover is more of the ticket here.
On my car which is still a stock turbo I can easily high mid 130 load numbers which is positive pressure very early in the rpm range. In these ranges the Open Loop setting is "140". This factory setting obviously works until we tune the cars... MIVEC for instance would make us spool faster and hit higher load areas sooner requiring a change in more than just the standard fuel map.
I saw somewhere mentioned by mrfred I believe (maybe this thread) that the ECU when in closed loop targets 14.7 afr no matter what the fuel map says. If this is in fact true, the extreme lean conditions would be apparent when hitting positive boost areas quickly with no time for the ecu to compensate and by the time it could you've crossed the open loop crossover point anyway and are now running off the fuel map. Someone that has read the code would need to confirm this...
My opinion is if that is the case lowering the crossover point makes complete sense and why it helped scheides...
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Joined: May 2010
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From: Sydney
My lean out issue seems to have gotton worse after a track day. Im on E85 and when the car is cold and im backing it out of the garage or now even under 2000rpm it leans out and is a bit pooi to drive. sorry neibours, have to give it a bit more revs now till I get this sorted! All my fuel trims are within 2% and my WOT is where it should be......
LOL.
https://www.evolutionm.net/forums/9524308-post10.html
https://www.evolutionm.net/forums/9524308-post15.html
https://www.evolutionm.net/forums/9524308-post19.html.
Or figure it out after the engine blows from going lean too often, one path is much easier to take.
Yes, Lean Throttle Tip in on larger injectors can be countered by changing over the Open loop crossover tables to switch to open loop earlier than the 120-140 load that the stock tables have in them. When the ECU is operating in closed loop those table entries are just for show, they really only serve to give you a smoother transition where the crossover takes place. While keeping the crossover values higher will keep it in closed loop 14.7 afr longer for better gas mileage, if it is out of it's adjustment range you need to force it to open loop earlier and adjust the tables to bring it back to a smoother progression and getting richer as load (and boost) increases.
Typical AFR Goals when I tune (load numbers will vary based on MAF scaling, injector scaling and other changes):
Closed Loop = 14.7 AFR (will swing from 13.5 - 15.5 at cruise or light throttle) (0-100 Load)
Open Loop 5 psi = 13.5 AFR (~125 Load)
Open Loop 10 psi = 13.0 AFR (~150 Load)
Open Loop 15 psi = 12.5 AFR (~175 Load)
Open Loop 20 psi = 12.0 AFR (~200 Load)
Open Loop 21+ psi = 11.0 - 11.5 AFR (based on goals, I prefer a cleaner running 11.5 with no knock) (200+ Load)
You can choose to run richer at lower loads but gas mileage will suffer, the above guide is more a limit of the leanest I would go.
Last edited by Hiboost; Nov 3, 2011 at 09:46 AM.
I've been saying that all along, seems people ignore my good advice that I give based on real world testing too often.
LOL.
https://www.evolutionm.net/forums/9524308-post10.html
https://www.evolutionm.net/forums/9524308-post15.html
https://www.evolutionm.net/forums/9524308-post19.html.
Or figure it out after the engine blows from going lean too often, one path is much easier to take.
Yes, Lean Throttle Tip in on larger injectors can be countered by changing over the Open loop crossover tables to switch to open loop earlier than the 120-140 load that the stock tables have in them. When the ECU is operating in closed loop those table entries are just for show, they really only serve to give you a smoother transition where the crossover takes place. While keeping the crossover values higher will keep it in closed loop 14.7 afr longer for better gas mileage, if it is out of it's adjustment range you need to force it to open loop earlier and adjust the tables to bring it back to a smoother progression and getting richer as load (and boost) increases.
Typical AFR Goals when I tune (load numbers will vary based on MAF scaling, injector scaling and other changes):
Closed Loop = 14.7 AFR (will swing from 13.5 - 15.5 at cruise or light throttle) (0-100 Load)
Open Loop 5 psi = 13.5 AFR (~125 Load)
Open Loop 10 psi = 13.0 AFR (~150 Load)
Open Loop 15 psi = 12.5 AFR (~175 Load)
Open Loop 20 psi = 12.0 AFR (~200 Load)
Open Loop 21+ psi = 11.0 - 11.5 AFR (based on goals, I prefer a cleaner running 11.5 with no knock) (200+ Load)
You can choose to run richer at lower loads but gas mileage will suffer, the above guide is more a limit of the leanest I would go.
LOL.
https://www.evolutionm.net/forums/9524308-post10.html
https://www.evolutionm.net/forums/9524308-post15.html
https://www.evolutionm.net/forums/9524308-post19.html.
Or figure it out after the engine blows from going lean too often, one path is much easier to take.
Yes, Lean Throttle Tip in on larger injectors can be countered by changing over the Open loop crossover tables to switch to open loop earlier than the 120-140 load that the stock tables have in them. When the ECU is operating in closed loop those table entries are just for show, they really only serve to give you a smoother transition where the crossover takes place. While keeping the crossover values higher will keep it in closed loop 14.7 afr longer for better gas mileage, if it is out of it's adjustment range you need to force it to open loop earlier and adjust the tables to bring it back to a smoother progression and getting richer as load (and boost) increases.
Typical AFR Goals when I tune (load numbers will vary based on MAF scaling, injector scaling and other changes):
Closed Loop = 14.7 AFR (will swing from 13.5 - 15.5 at cruise or light throttle) (0-100 Load)
Open Loop 5 psi = 13.5 AFR (~125 Load)
Open Loop 10 psi = 13.0 AFR (~150 Load)
Open Loop 15 psi = 12.5 AFR (~175 Load)
Open Loop 20 psi = 12.0 AFR (~200 Load)
Open Loop 21+ psi = 11.0 - 11.5 AFR (based on goals, I prefer a cleaner running 11.5 with no knock) (200+ Load)
You can choose to run richer at lower loads but gas mileage will suffer, the above guide is more a limit of the leanest I would go.
I plan to flash my car for the drive home from work with the crossover points lowered. Golden gave me some info I am going to try first and go from there if needed. I really think it will totally solve this issue, especially when combined with the accel table if that works properly.
I have the open loop load set at 80 from 1500 to 3000 and it helps, but I find that it throws a check engine light here and there. I forget the code number but its always the same something. The car is trying to compensate for the lean mixture I believe. Correct me if im wrong. I will be checking the code tom. just to confirm, but do any of you get a cel thrown after dropping the loop???
I have the open loop load set at 80 from 1500 to 3000 and it helps, but I find that it throws a check engine light here and there. I forget the code number but its always the same something. The car is trying to compensate for the lean mixture I believe. Correct me if im wrong. I will be checking the code tom. just to confirm, but do any of you get a cel thrown after dropping the loop???
It's a p0171 is the code I have thrown before and im just assuming its the same code. It never popped up while running with the stock loop numbers but it seems to come back when they are dropped. It will go away after driving the car for a bit, but its just annoying seeing it. I am sure this isnt a problem tho anyways
I lowered my crossover points to what Golden suggested and have had no codes thrown.
I also have nearly completely eliminated any lean issues in the areas I had before. I did some initial fuiel map tuning and its pretty dang close. I need to fine tune it and then start looking at the accel table again. I set it back to stock for a 2011 while i played with lower open loop settings.
So in a nutshell, lowering the crossover point is in fact the way to fix this issue.
I also have nearly completely eliminated any lean issues in the areas I had before. I did some initial fuiel map tuning and its pretty dang close. I need to fine tune it and then start looking at the accel table again. I set it back to stock for a 2011 while i played with lower open loop settings.
So in a nutshell, lowering the crossover point is in fact the way to fix this issue.
As soon as I hit positive pressure I hit 13's and quickly into mid 12's. Now I need to fine tune it a little better but its almost spot on in the lower rpm ranges.
Where you also need to be careful is cruising on the highway. There are a couple points at the crossover point where my car cruises at 16.2 AFR. I've started tuning there to dial it to about 15.5.
Correct, this is what I did.
As soon as I hit positive pressure I hit 13's and quickly into mid 12's. Now I need to fine tune it a little better but its almost spot on in the lower rpm ranges.
Where you also need to be careful is cruising on the highway. There are a couple points at the crossover point where my car cruises at 16.2 AFR. I've started tuning there to dial it to about 15.5.
As soon as I hit positive pressure I hit 13's and quickly into mid 12's. Now I need to fine tune it a little better but its almost spot on in the lower rpm ranges.
Where you also need to be careful is cruising on the highway. There are a couple points at the crossover point where my car cruises at 16.2 AFR. I've started tuning there to dial it to about 15.5.
OBD-II Trouble Code: P0171 System Too Lean (Bank 1)
Basically get the AFR's correct for all conditions and that error code will stop hassling you!
Leaning out at cruise will upset the car if it is dipping in and out of closed loop trying to compensate. Worst case start on the rich side of things as it will rarely complain about it being too rich, then lean out in steps until the AFR's are a smooth progression like I listed above. Cruising at 16.5 is definitely a bad idea, it needs to average 14.7 and maybe swing +-1 point. It can occasionally dip leaner or richer of course but it can't hover there without throwing a code if it is too lean under load.
Good luck!