More Tuning Questions (1 at a time now)
09-09-2010, 09:59 PM
#1
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More Tuning Questions (1 at a time now) I think I asked too many questions in my first thread...
Trying to get my BLMs straight before I get too caried away with the tuning. I like where I am with my spark advance for now, but it needs tweaking. First, am I correct in getting the BLMs correct before you can really tune anything else? Second, my fuel trim table was stock, which is all over the place. Should I set all fuel trims to 1.0 and log, read long term BLMs, then tune, and repeat until I get a good average of around 128? Or is there a better way? This is just for idle and cruising.
It was consistently lean in closed loop so I adjusted the MAF calibration tables, now it's consistently rich. I guess I should have left that alone and did the BLM / Fuel trim tune 1st. The right side is leaner than left, and looking at my stock fuel trims, I can see why.
Any suggestions?
Trying to get my BLMs straight before I get too caried away with the tuning. I like where I am with my spark advance for now, but it needs tweaking. First, am I correct in getting the BLMs correct before you can really tune anything else? Second, my fuel trim table was stock, which is all over the place. Should I set all fuel trims to 1.0 and log, read long term BLMs, then tune, and repeat until I get a good average of around 128? Or is there a better way? This is just for idle and cruising.
It was consistently lean in closed loop so I adjusted the MAF calibration tables, now it's consistently rich. I guess I should have left that alone and did the BLM / Fuel trim tune 1st. The right side is leaner than left, and looking at my stock fuel trims, I can see why.
Any suggestions?
09-10-2010, 08:49 AM
#3
Search for injuneers page on split blms.
Adjusting MAF tables IS the way you get BLMs right..
You need to be looking at the airflow for the area you want to tune and only /make changes there. Don't make huge changes from one cell to another though, smoothly transition it. We havbe crappy resolution in those tables. Too big of a jump and the car will run like crap when it transitions across the adjusted areas
Adjusting MAF tables IS the way you get BLMs right..
You need to be looking at the airflow for the area you want to tune and only /make changes there. Don't make huge changes from one cell to another though, smoothly transition it. We havbe crappy resolution in those tables. Too big of a jump and the car will run like crap when it transitions across the adjusted areas
09-11-2010, 09:41 AM
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So leave the fuel trim table stock? Isn't that the only way to adjust left to right? The MAF will adjust AFR on all 8 cylinders. So how do I get the left to equalize with the right?
I will look for injuneers page, though...probably has all the answers..
I will look for injuneers page, though...probably has all the answers..
09-12-2010, 10:04 PM
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Well it looks like they're only split at idle and near idle. I'm using freescan: is there a place that explains all the BLM cells? or do you just have to figure that out on your own? I thought there was only 16, but mine goes up to 18. I see 16 is idle and 15 is high rpm, high map....seems kind of screwed up to me.
Did you mean the MAF will not adjust all 8 cylinders individually because I know that only affects airflow to the manifold? The fuel trim is the only way to adjust AFR on 1 side or 1 cylinder, right?
Did you mean the MAF will not adjust all 8 cylinders individually because I know that only affects airflow to the manifold? The fuel trim is the only way to adjust AFR on 1 side or 1 cylinder, right?
09-12-2010, 10:08 PM
#7
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I think I'll just get some new O2's and see if that changes anything. I hear factory GM's are the way to go. Any opinions on o2 sensors? and where would I get GM factory replacements? dealership?
I also read that the throttle body adjustment screw can play a role in split BLMs. Anybody know about that?
I also read that the throttle body adjustment screw can play a role in split BLMs. Anybody know about that?
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09-12-2010, 10:13 PM
#8
Read these, they will help
http://www.injuneer.com/ScanMast.html
http://www.noid.org/~lj/PCM%20Tutorial/PCMtutorial.htm
http://www.noid.org/~lj/PCM%20Tutorial/SplitBLMinfo.htm
http://www.carprogrammer.com/Z28/PCM...k%20tuning.htm
I have a lot more resources and reference material that I read, but start on those and really take them slow and comprehend them, play with the tuning parameters, go back and read them again, etc.
The better grasp you get on exactly how the PCM functions, why it does some of the things it does, and the logic it's based on, the easier it will be for you to do a quality job on your tune, and to solve problems that arise, etc.
http://www.injuneer.com/ScanMast.html
http://www.noid.org/~lj/PCM%20Tutorial/PCMtutorial.htm
http://www.noid.org/~lj/PCM%20Tutorial/SplitBLMinfo.htm
http://www.carprogrammer.com/Z28/PCM...k%20tuning.htm
I have a lot more resources and reference material that I read, but start on those and really take them slow and comprehend them, play with the tuning parameters, go back and read them again, etc.
The better grasp you get on exactly how the PCM functions, why it does some of the things it does, and the logic it's based on, the easier it will be for you to do a quality job on your tune, and to solve problems that arise, etc.
