dan_t

I would have thought this would have been simple but the more i look im not sure if its even possible?

I've always found that my engine likes to run slightly richer than 14.7 - infact a BLM/INT of around 120 seems just perfect. Of course when I make the change in the BIN I get a few miles of nice driving and then it self learns and goes back to how it was. (Although it drives fine, it feels "touchy" to small throttle movement etc - being just on the rich side smooths this out)

Open loop is nicer to drive than closed most of the time, but obviously MPG suffers badly.

What can I do to make closed loop tune for a richer AFR / BLM??

Orr89RocZ

iTrader: (20)

Isnt there a setting in the bin for commanded air fuel ratio value that you can possibly change to a richer value so the computer shoots for a richer condition?

dan_t

There is but this gets ignored when the o2 sesor is swinging. What I need to do is say... get my o2 to swing at 650mv? I see there are several O2 tables I'm just not sure which to adjust? There all labeled "IDLE" and I want this to happen globaly.

Orr89RocZ

iTrader: (20)

i see. Swinging the o2 milivolts will help, i'm just not too familar with the 730 aujp stuff. I know it says idle but it would make sense to me that it would happen all the time whenever its in closed loop

dan_t

yes, I think your right... reading the XDF from AUJPV4 makes a lot more sense, and doesn't include the "Idle" which was throwing me off track... with this and the O2 Constants excel sheet I found on here I beleive I can do what I want

305sbc

iTrader: (3)

Dan, This is a completely different perspective, but you might want to first look a bit closer as to why you're getting the results you get now. There could be other factors causing this other than "your engine just likes it". You know there could be specific reasons, or other problems that make it look like your engine likes a richer AFR, least of which could be an O2 reading that is a little off due to exhaust leaks, sensor temp, or some other fault. Unless your camshaft is stock or near stock, I wouldn't completely trust a narrow or wide-band O2 to be exactly right. I know where you're coming from, but you might want to consider running open-loop 100% of the time and having complete user control over the fueling.

Other factors that effect how much fuel an engine seems to "like" are excess spark advance and/or hotspots forming around the combustion chamber.
More advance will like more fuel, but doesn't always make best power or best fuel economy that way.
Uneven cooling around the combustion chambers and/or overheating sparkplugs (stock range) will also make the engine "like" extra fuel to cover up these problems.

I'm just saying you might want to look a little closer before you apply your fix. Adjusting the closed-loop parameters may work in your case, but applying the closed-loop alogrithm to a non-stock engine is often problematic for many reasons. The O2 feedback system works best with stock camshaft and stock exhaust.

JP86SS

iTrader: (1)

Idle has its own tables that can be adjusted.
The tables in the spreadsheet only deal with the "off-Idle" driving conditions (Part Throttle only, not WOT)
The graphs let you see the changes needed/desired without crossing you up between tables. Its easy to change one table and then not have the relationship maintained. They all work together as described in RBob's writeup. Seeing the relationship helped me adjust mine because I was all over the place before charting them out.
Certainly check that everything is operating before changing them, If there is a mechanical problem and you fudge it in the tables, when you do get the problem corrected you'll have additional troubles.

dan0617

I have a 165 MAF car, 6E, and am pretty new at this but.....

Why do you guys running closed loop with modified cars let the blms run? I found it best so far to run closed loop with the blms locked. I set the min and max blms to 128, but let the integrator run wild (Like min 90 and max 160). When datalogging and tweaking the tune I could dial it in much easier, by making changes to get the integrator as close to 128 as possible. I originally did this and figured on unlocking the blms when done tuning but the wideband stays much closer to 14.7 all the time with the blms locked at 128 all the time. Also, I can jump on the throttle and the WOT AFR is now always about the same. With the blms unlocked it seemed as though sometimes WOT would be too rich and sometimes too lean, depending on how fast I was going or what gear I was in when I jumped on it. That issue is gone too with the locking of the blms.

I, too, wanted to richen up the cruise to about 13.5 afr and still run closed loop. I tried injector constants, no luck. Tried the commanded afr, no luck. Any combo of tries always leads back to 14.7, unless I run open loop. But then I figured out a simple cheat. I set the highway mode to come on at about 35 mph, come on after 3 seconds, stay on for 3 minutes, set the max LV8 to stay in highway mode to 160, and set the highway mode afr to be 13.5. It works. It actually runs a little richer in some areas, which I haven't had time to work on yet, but always hangs around 13.5 at cruise rpms. I tried setting it to 12.0 and sure enough at cruise it held 12.0 afr. Went back to 13.9 for now. Not sure I'm going to run this way forever but for now it gives me the least amount of cam surge. Again, this is a MAF car running 6E, but if you have a highway mode maybe you can play around with different MPH activation points and different AFR's in highway mode to see how it works for you. I'm not sure I'd want the blms running if you do this because they could be pretty far out of whack when it comes out of highway mode. Integrator only seems to work the best for me in CL.

Z69

For everyone that didn't look at his sig...
dan_T is running a cc306 and a MT. That cam has a lot of overlap.
Most seem to give up on this cam and idle tuning and swap to another cam or learn to live with it. Personally I'd swap to a Voodoo 233/241 @ 50 HR.

120blm means the ecm is pulling fuel and you need to lower the VE & the o2 MV swing point. 120 isn't bad for that cam.....

The o2 tables for 8D are labeled fast and slow. I forget when they swap but it's between 1000 & 1500 rpm. I'd swear it's when the idle flag gets set but it's been a long time since I read that part of the code.

Make sure you are getting good logs and document each change and review the logs for the response. Hopefully you can tune in RT & have a WB or your going to be at this a while.
Since your running V4.
Turn off the idle SA table. This will eliminate one variable to deal with for now. Set the idle area for you cam to a high value like 28-30 and have it slope down some for letting the clutch out. I think Traxion ran this cam and added a whole bunch of timing below his converter stall. See the axcn tables for an MT. This may be difficult since you don't have a lot of room on the map scale with that cam.
Get the spark done first and try to make it smooth in the entire idle area.
Note- the cold start <112f SA is the last column of the table. No Map used.

For your cam I'd set OL idle to a little higher than what the rpm is after you let the clutch out in 1st for an easy take off from a stop. That way your not transitioning during clutch movement.
Now tune you idle pw by feel/smell in open loop in the driveway. Just hold a steady throttle at various RPM and adjust your VE after setting the AFR to the desired # in the OL table. This will give you a trend to see how to adjust the area near where you let the clutch out. Make sure the CMD afr matches your tables while in OL and the BLM/INT is 128.

You might just set OL to 2k and tune all the way to there 1st.

With this setup close to something tolerable to you. You will have a log of PW and O2 MV. Now you can change the OL setting lower and see what you need to do with the VE and O2 swing numbers. IE set your swing to follow the voltage you get from the log and then adjust the VE down to get the BLM in line. You'll see your PW drop to near your log values as you lower the VE.
This is a lot easier in 6E since it has a CL airflow vs mv table so you can set the mv midpoint (afr) where ever based on flow instead of map. Don't play with the Hwy MD as mentioned earlier. Your doing the same thing this way but using the correct table.
A WB will be very useful once you get the rpm's up little and the o2 added from reversion is a considerably lower pecentage of the exh gas.

Also, I don't think you'll be able to get your swing points down to 13.5. The stock NB just isn't accurate that far from 14.7.

Orr89RocZ

iTrader: (20)

I ran a very similar cam in my 383 with even more overlap and did have a problem getting BLMs at idle to get near 128. Changing the swing points helps get the BLMs in line and keeping the air fuel around 14.7-15.0. My car idled good at that air fuel, but it needed about 1000 rpm idle speed and 26-28 degrees spark at idle.

Those bigger cams need spark advance and abit more idle speed for sure, and if the air fuel is decent, like mid high 14s or so, it should stable out. Richer my car was, the more erratic the idle was. Too lean and it wanted to die at times.

It may be borderline impossible to reach 128 blm at idle with a cam that big but getting close to it is possible and good enough. As long as the car is happy idling, i'd be happy with it.


But during cruise and such, you should beable to reach 128 blm. I was able to get it there in the short while I ran in closed loop. Switching to pure open loop was easier to tune in my car (MAF 165ecm) so i stuck with it. But closed loop ran fine. If yours is touchy and being richer clears it up, try playing with the timing. Take a few degrees out and see what happens. Usually adding timing leans the mixture out and taking some out could slighly increase it. It may clear up your problems if you cant command a mid 13's air fuel ratio which is a good ways off narrowbands 14.7 comfort spot