Help with Funky AFR
Then it is adding fuel if it is positive. 21 is almost maxed out. When does it hit 21? Idle? cruise?
this is interesting reading for me, I always thought the trims were used only during closed loop. The o2 feedback goes to zero during wot so I just assumed that whole aspect was moot as far as your fuel map was concerned.
Since the trims are independent, low and mid, one would think they are confined to their own areas of closed loop.
So if his idle or cruise is adding fuel that would mean his latencies are "lean" which would impact his fuel map to go lean from the get go. As latencies effect is impacted over time by the trims, but latencies themselves are not changed. It is confusing because, as the trims are moving there is no change in afr, because the trims are an indication of what the ecu is already doing, not what it is going to do in a while. But as you know this is all intended to keep the car at 14.7, so I still don't know if trims can effect the fuel map.
Sorry for the sporadic thinking, its early.
Since the trims are independent, low and mid, one would think they are confined to their own areas of closed loop.
So if his idle or cruise is adding fuel that would mean his latencies are "lean" which would impact his fuel map to go lean from the get go. As latencies effect is impacted over time by the trims, but latencies themselves are not changed. It is confusing because, as the trims are moving there is no change in afr, because the trims are an indication of what the ecu is already doing, not what it is going to do in a while. But as you know this is all intended to keep the car at 14.7, so I still don't know if trims can effect the fuel map.
Sorry for the sporadic thinking, its early.
this is interesting reading for me, I always thought the trims were used only during closed loop. The o2 feedback goes to zero during wot so I just assumed that whole aspect was moot as far as your fuel map was concerned.
Since the trims are independent, low and mid, one would think they are confined to their own areas of closed loop.
So if his idle or cruise is adding fuel that would mean his latencies are "lean" which would impact his fuel map to go lean from the get go. As latencies effect is impacted over time by the trims, but latencies themselves are not changed. It is confusing because, as the trims are moving there is no change in afr, because the trims are an indication of what the ecu is already doing, not what it is going to do in a while. But as you know this is all intended to keep the car at 14.7, so I still don't know if trims can effect the fuel map.
Sorry for the sporadic thinking, its early.
Since the trims are independent, low and mid, one would think they are confined to their own areas of closed loop.
So if his idle or cruise is adding fuel that would mean his latencies are "lean" which would impact his fuel map to go lean from the get go. As latencies effect is impacted over time by the trims, but latencies themselves are not changed. It is confusing because, as the trims are moving there is no change in afr, because the trims are an indication of what the ecu is already doing, not what it is going to do in a while. But as you know this is all intended to keep the car at 14.7, so I still don't know if trims can effect the fuel map.
Sorry for the sporadic thinking, its early.
The reason for fuel trims in an EFI car is to allow for degradation in the fuel system over time. Forget about modified cars for a moment and think about stock cars that are driven for thousands of miles by people who don't constantly monitor things. As miles are put on, wear and tear affect the fuel system, whether the injectors get clogged with deposits, the fuel pump wears out or anything else that would effect fuel delivery. The ECU will determine if there is a need to modify the fueling during closed loop. If the pump was old, then there may be a need to increase IPW to keep the mixture stoich. If there was a constant need for a correction, then it would be carried over to the long term trim. Now, if you had a deficient fuel pump, it would cause in issue when in open loop. Thats where the long term trim comes in, by making the correction in open loop.
http://www.sr20deracing.com/EVO/2007-07-13-094902.csv
Last edited by nj1266; Jul 18, 2007 at 07:58 AM.
EvoM Guru
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It getting kinda interesting now. I picked up a used set of Evo IX injectors (less than 8k miles on the car) a few weeks ago and had them sent to RC Eng for flow testing and cleaning. In the as received condition, three were down to 550 cc/min, and one was down to something like 535 cc/min. After cleaning, all were back up to 560 cc/min. So I guess that's an example of an almost immediate change that occurs.
Today I did two long logs. One on my way to work and one on my way back. Please check the fuel trims and O2 feedback and tell me if they are OK.
On the way to work
http://www.sr20deracing.com/2007-07-18-094232.csv
On the way from work
http://www.sr20deracing.com/2007-07-18-135223.csv
These files log 35-40 mintues of data. Most of the driving was @ cruising. There is one WOT run on the first log. I did not log AFR. For some reason Mitsulogger isn't logging my AFR. Evoscan does, but not Mitsulogger
On the way to work
http://www.sr20deracing.com/2007-07-18-094232.csv
On the way from work
http://www.sr20deracing.com/2007-07-18-135223.csv
These files log 35-40 mintues of data. Most of the driving was @ cruising. There is one WOT run on the first log. I did not log AFR. For some reason Mitsulogger isn't logging my AFR. Evoscan does, but not Mitsulogger
well your trims are adding lots of fuel.
I believe the routine would be to reduce your injector scaling since both trims are positive. However you have stock injectors and inputs. So I am thinking something is messing with your intake.
I believe the routine would be to reduce your injector scaling since both trims are positive. However you have stock injectors and inputs. So I am thinking something is messing with your intake.
Yes, I did. When I swapped back to stock, I did the same thing. All the the boost hoses are connected. I will double check one more time to make sure that everything is connected.
Can I scale my injectors back even if I am running stock injectors? By how much should I scale them? If that fixes the problem, then I am willing to do it. The car is a pain to tune this way.
I think I found the problem. I feel very embarassed right now 
I checked the intake system just now and noticed that I forgot to tighten the clamp that attaches the intake hose to the MAF. I was under the car checking the boost hoses (I have no undertray for now) and moved the clamp and it was LOOSE.
I hope that solves the problem. I really do even if I feel like an idiot, but I will be a happy idiot nonetheless
I checked the intake system just now and noticed that I forgot to tighten the clamp that attaches the intake hose to the MAF. I was under the car checking the boost hoses (I have no undertray for now) and moved the clamp and it was LOOSE.I hope that solves the problem. I really do even if I feel like an idiot, but I will be a happy idiot nonetheless
Last edited by nj1266; Jul 18, 2007 at 10:44 PM.
I logged the fuel trims on the way to work and they were very different from last time. The STFT was @ 0 and only towards the very end of the drive did it climb to 1. Yesterday the STFT hit 9 by the end of the trip. The O2 feedback was in the single digits @ cruise (between 4-6) and in the teens @ idle.
I am very encouraged by this result.
I am very encouraged by this result.