Thinking of going OLMAF

[RevGTO]

Hey guys, would like your input ...

I have long tube headers on my LS1 Firebird and keep getting DTC's about the O2 sensors' switching being off. I've read plenty of threads on tech about the various sensors that are supposed to provide solutions, and a lot of guys just keep having the problem.

Plus it seems like I tune my MAF and such and get my fuel trims down and then in time they're up again. My car just wants to run rich and I'm tired of that, too.

I'm thinking of upgrading to COS5 and ditching closed loop operation. I'm concerned about driveability and getting the fueling tables right, but I've read the threads and tutorials and it sounds doable.

I assume I'd have to do an AutoVE first (I'm running a downloaded Holdencrazy table from a car with similar mods). My car has the 12212156 OS and I have an LM-1.

What are your thoughts? This is my daily driver in all kinds of weather and conditions, and I do take it to the track.

I appreciate any guidance, tips or instructions on whether to do it and how to do it properly.

[ringram]

As long as you dont need to pass a obdii scan test for emissions or anything its a reasonable option.
Like you say get your ve table right first then check/fix maf flow rates and off you go. You can leave out the O2 sensors after that. MAF seems to follow the seasons slightly easier than SD mode as it deals with mass variation intrinsically. Whereas SD accuracy needs more effort on intake and charge temp tables.

[Aloicious]

I run my daily driver truck in OLMAF. what I do is get the VE in line using AUTOVE, then work on the MAF calibration with a simmilar methood the AUTOVE but using BENs to correct the MAF curve (make sure to change the MAF/VE blend from 4000 rpm to 400 so the calibration will be running pretty much only off the MAF). I'm at work right now so I don't have all the table names and info with me, but do a search for autoMAF, or MAF tuning for info on it. then I basically set everything back (DFCO, Cat protection, etc) except for the O2 stuff (disable the O2 codes so you don't get those DTC's), so it stays in OL. I'm not even running a COS either, just the regular stock OS, I believe its 12212156 (its based off the holdencrazy 2002 express van 5.7L stock tune)

I've had good success with OLMAF, my AFR's are more consistant and where I want them to be than in CL, and I have good driveability.

[Aloicious]

As long as you dont need to pass a obdii scan test for emissions or anything its a reasonable option.
Like you say get your ve table right first then check/fix maf flow rates and off you go. You can leave out the O2 sensors after that. MAF seems to follow the seasons slightly easier than SD mode as it deals with mass variation intrinsically. Whereas SD accuracy needs more effort on intake and charge temp tables.

you beat me to it, :sly:

[RevGTO]

I would think you would need to run a COS to have the B3647 fueling table ... if you don't have 02's attempting to keep your AFR's in line, wouldn't you need this table? Is the standard B3605 open loop table adequate across the full range of fueling needs?

Anyone have any examples of how they've set up B3647?

Why is turning the MAF down to 400rpm in order to operate across the full rpm band necessary when running this way? The tutorial doesn't mention anything about doing this when describing "semi-open loop." If your VE is spot on, wouldn't you be ok with MAF above 4000?

Thanks for the help guys ... don't meant to overdo it on the questions, but trying to get a handle on this to avoid pitfalls and problems.

[Aloicious]

I would think you would need to run a COS to have the B3647 fueling table ... if you don't have 02's attempting to keep your AFR's in line, wouldn't you need this table? Is the standard B3605 open loop table adequate across the full range of fueling needs?

Anyone have any examples of how they've set up B3647?

Why is turning the MAF down to 400rpm in order to operate across the full rpm band necessary when running this way? The tutorial doesn't mention anything about doing this when describing "semi-open loop." If your VE is spot on, wouldn't you be ok with MAF above 4000?

Thanks for the help guys ... don't meant to overdo it on the questions, but trying to get a handle on this to avoid pitfalls and problems.


yeah a COS is the only way to have B3647, but the b3605 works fine and with transient tables like PE/DFCO etc. that handle differing settings it works out fine. 3647 will give you more control as far as the RPM vs load range, either way should work fine. I haven't had problems running the stock OS in OLMAF for the past 2-3 months or so, driven daily. I like the stock OS because I don't want any semi-open loop, I like fully OL running at 1.00 EQ.

turning the MAF blend down to 400 is ONLY for tuning the MAF curve. you're basically trying to turn OFF the VE so you can tune the MAF w/o interference. the same reason you turn off the MAF and unplug it to do VE tuning, just the other way around, you definantly want to turn the blend back to 4000 after you're done working over the MAF table. there's no tutorial on doing autoMAF tuning. do a search for it, you should find some good info on how to do it.

the MAF curve and blend have nothing to do with semi-open loop, thats a feature of the COS's that will use your stock O2 sensors to trim the fuel anywhere you have 1.00 EQ in B3647.

[RevGTO]

Ok, great - thanks. So then staying on the stock OS without B3647 I'd keep PE. And yes, I want to be in full open loop because I don't think my O2's are going to ever be completely right with my long tubes, leading to constant and unecessary fuel trimming.