MEFI adjustment ideas for rich idle on a Procharged motor?
08-16-2012, 08:54 PM
#42
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42's\
For 50's just scale it back.. assuming the FP hasn't been changed. If it has figure the pressure factor, scale the injectors and apply the fp factor. A great place to start.
Another thing to note that I have seen overLOOKed...
during an increase in RPM (regardless of other elements) the ECU only calculates based on where is has BEEN, not where it is going.
For 50's just scale it back.. assuming the FP hasn't been changed. If it has figure the pressure factor, scale the injectors and apply the fp factor. A great place to start.
Another thing to note that I have seen overLOOKed...
during an increase in RPM (regardless of other elements) the ECU only calculates based on where is has BEEN, not where it is going.
08-17-2012, 11:00 PM
#43
His idle numbers are in the ball park even with the bigger injectors so something is not right.
As tuner mentioned perhaps some of the AE or DE values gots zeroed out or put to ridiculously low values and are killing the BPW.
Heck, check all the scalars and multipliers to make sure they aren't throwing things out of whack.
As tuner mentioned perhaps some of the AE or DE values gots zeroed out or put to ridiculously low values and are killing the BPW.
Heck, check all the scalars and multipliers to make sure they aren't throwing things out of whack.
08-17-2012, 11:02 PM
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08-17-2012, 11:14 PM
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How lean does the MTX-L go when it dies?
I have the same wide-band system and I don't believe the soot will be a factor. I've had mine as rich as 10.8 at idle on baseline tuning and the wide band didn't give me one problem, motor wasn't happy but it did sound like a top fuel motor
Let's assume then the wide band system is calibrated correctly. I can't see how a 2.5 bpw will give you an 11.0 reading. We need to figure out this issue before things move forward.
The 35 kPa seems off to me. That's heavy vacuum from my experience. I would think it should be closer to 50ish.
Correct .xdf file in TunerPro?
Looking at your table values you have plenty of fidelity left to make small BPW changes and thus AFR changes. I have to drive a 42lb injector from 2.2 all the way to 4.0+ to get the AFR from 13.7 or so down to 10.8, therefore your min change should not go from 11.0 to lean stall. Does your IAC surge a lot?
I have the same wide-band system and I don't believe the soot will be a factor. I've had mine as rich as 10.8 at idle on baseline tuning and the wide band didn't give me one problem, motor wasn't happy but it did sound like a top fuel motor
Let's assume then the wide band system is calibrated correctly. I can't see how a 2.5 bpw will give you an 11.0 reading. We need to figure out this issue before things move forward.
The 35 kPa seems off to me. That's heavy vacuum from my experience. I would think it should be closer to 50ish.
Correct .xdf file in TunerPro?
Looking at your table values you have plenty of fidelity left to make small BPW changes and thus AFR changes. I have to drive a 42lb injector from 2.2 all the way to 4.0+ to get the AFR from 13.7 or so down to 10.8, therefore your min change should not go from 11.0 to lean stall. Does your IAC surge a lot?
No IAC surge, it shows 0.
08-18-2012, 01:42 AM
#46
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I believe the issue is the 2 bar map cuts the table resolution in half. The MEFI 1 and MEFI 2 don't have much resolution to start off with, so cutting it in half leads to a very sharp difference between cells that is quite sensitive to small changes. Many moons ago I ran into this problem using a stock 95 LT1 controller on a boosted setup with a 2 bar, and it was difficult tuning it. This is a guess on my part, and I never understood why the MEFI 2 even had a flag to set a 2 bar map, as there is no table for boost correction. I'd probably go back to the 1 bar map and get it tuned, boosted MEFI 1 style. Many have run MEFI 1's with boost, using boost referenced regulators and throwing fuel at it in the high part of the map. Certainly a sub-optimal solution and crude, but it does work and utilizes what resolution there is in the MEFI 2 tables, which are much better than the MEFI 1's.
Bob
Bob
08-21-2012, 07:55 PM
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I believe the issue is the 2 bar map cuts the table resolution in half. The MEFI 1 and MEFI 2 don't have much resolution to start off with, so cutting it in half leads to a very sharp difference between cells that is quite sensitive to small changes. Many moons ago I ran into this problem using a stock 95 LT1 controller on a boosted setup with a 2 bar, and it was difficult tuning it. This is a guess on my part, and I never understood why the MEFI 2 even had a flag to set a 2 bar map, as there is no table for boost correction. I'd probably go back to the 1 bar map and get it tuned, boosted MEFI 1 style. Many have run MEFI 1's with boost, using boost referenced regulators and throwing fuel at it in the high part of the map. Certainly a sub-optimal solution and crude, but it does work and utilizes what resolution there is in the MEFI 2 tables, which are much better than the MEFI 1's.
Bob
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08-21-2012, 09:00 PM
#48
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Hi Bob good to hear from you. Based on what you are saying do I need to multiply the MAP axis marks by 2 in Tuner Pro when tuning with the 2 ATM MAP sensor? Does the ECM scale down to 0 on the MAP scale? That would explain why I can't lean out the tune under strong vacuum.
The only way to tell would be to watch scanner pro while it's running.
08-25-2012, 10:33 PM
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If you lose half the resolution does that mean the MAP reference numbers on the axis no longer correlate to the MAP reading that I see on the 2 ATM MAP sensor in Scanner Pro?
It sounds like I need to multiply the TunerPro MAP numbers by 2 to figure out where I am on the table with a 2 ATM MAP.
The MAP and BPW readings in ScannerPro do not directly correlate with any point in the RUN FUEL vs MAP & RPM table of Tunerpro
Last edited by yellowjacket; 08-25-2012 at 11:40 PM.
