SD2 Narrowband tracking poll

[TurboBob]

the allowable range includes 14.5 . I think it makes more sense to set your afr target closer to 14.7. The difference is minimal (in fact mine is still 14.5)



Bob

 

[missin' 2]

what version software are you running in the PL and PLC?

the narrowband stuff is enabled by setting the option to 2 (or add 2 to the number thats already there.)

then, any time your target AFR is between 14.6 and 14.8, the PL will close the loop with the stock O2, instead of the wideband.

Bob

Its the most recent. I just updated last night for flex fuel.

So target af meaning the number on the af table?

What if you have the lean cruise setup and that is set to 15 or higher? Still only works at 14.6 to 14.8?

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[TurboDave]

Lean cruise is a separate thing. Once all the things to activate lean cruise are met, it will kick into lean cruise.

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[TurboDave]

As a matter of fact, my speed parameter for lean cruise is set to 60mph. That way narrowband tracking pretty much takes care of all my urban cruising, and lean cruise will likely kick in out on the open highway.

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I target NB at 14.5 and LC at 15.8

 

[missin' 2]

As a matter of fact, my speed parameter for lean cruise is set to 60mph. That way narrowband tracking pretty much takes care of all my urban cruising, and lean cruise will likely kick in out on the open highway.

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I target NB at 14.5 and LC at 15.8

Any idea what your mpg is just curious what the best possible is. Since you are a picky tuner.

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[TurboDave]

Any idea what your mpg is just curious what the best possible is. Since you are a picky tuner.

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haven't been monitoring mpg's, but I did check on the last fill. It was 16.5. That was all urban driving no highway driving, and there may have been a strong pull or two thrown in there.

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[missin' 2]

just so I get a proper understanding on this im going to think out loud with you. I have nb tracking on option 2 target af table set to 14.7 for proper loads.

so with option 2 on, it looks like the nb tracking only works after 130 degrees when it goes into c/l. im guessing that would also go for the wide band c/l if option 2 was off.

so parameter 11 controls the fueling for anything under 130 degrees, idle or cruising? what determines the target af for that start up period?

 

[TurboDave]

Yes, for the most part parameter 11 does the fueling for Cold Startup(actually it's a value to add to or take away from the chip's cold start A/F). This gets a little complex so please hang with me here, I'm not that good at explaining this.
There is some control by the SD2 chip its self before handing over control to the TAF table when things get up to temp. I noticed this one day when I was monitoring the Data tab immediately after startup and while the engine was coming up to temp. On the upper left hand corner of the data page you'll see the box labeled ECM AFR. Take a look at its value right after a cold startup and you'll see it's indicating pretty rich!! BUT....its value does not correspond to any value being tracked under the bubble while also looking at the TAF table. So the chip has control during warm up. Also, the cold start fuel slowly richens up during warmup as a function of time as I understand it. Soooooo, if you just started the car up and were in monitor mode watching both the data tab and TAF table bubble during warm up, you'd notice the initial very rich ECM AFR value eventually climb to a point where it matches what the TAF value is for that rpm/map.

This all assumes Bob or Eric haven't changed something I'm not aware of. ;-)

Clear as mud, right?

 

[missin' 2]

Ya I guess that makes sense. I did see that today when I started it up.

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