ECMlink Leaning out Closed loop cruising

[bmxfelon420]

Hey all, I was just wondering what methods work best to lean out very low load cruising. I slightly bumped the top row in the OL table to 15.5:1 or so (on e85) and I'd like to know how to get the car to idle leaner. Do I just take some out of the airflow comp at that MAF reading? I'd think the fuel trims would get screwed up doing that though.

One thing I have noticed in my experiments is that you can make pretty large adjustments to deadtime without it really making much of a difference during cruising. Deadtime doesnt seem to affect Closed Loop as directly as MAFcomp does in that respect.

Anyways any suggestions are welcome.

 

[bmxfelon420]

Assuming your car is properly tuned, you simply adjust the Openloop DA tables to your desired AFR.

This will only work if your fuel and Airflow settings have been properly calibrated.

As for wanting to make everything leaner, is there a reason for this? If its for gas milage, you are unlikely to see any worthwhile results unless you spend an immense amount of time tuning.

Openloop targets apply to closed loop? I wasnt sure about that. If thats the case thats cool.

Since i have a wideband and MAP i considered just locking the car in OL to perfect the MAFcomp and then when i switch it back i'll know its right. I gotta pull a bit more deadtime i think though, It was cyclin in CL just fine but swinging a bit more rich than lean.

As for time, I drive 65 miles a day, I can log during all of it so adjustments are no big deal

 

[bmxfelon420]

Yeah I did some testing today and here's what I found:

If i set the OL targets, lock the car in OL, i adjusted my MAFcomp until it lines up perfectly. The AFRest and logged wideband are identical. The minute I switch it back to Closed Loop, it adds fuel to richen it back up. Is there something else i'm missing?

Another question along those lines, say I lock the car in OL and go speed density. Will the IAT compensate well enough for temperature to keep the car in open loop?

 

[lasthope05]

The simplest way is to run narrowband sim and change the crossover point for your specific wideband.

http://www.ecmtuning.com/wiki/v3narrowbandsim?s[]=narrowband&s[]=simulation

 

[bmxfelon420]

The simplest way is to run narrowband sim and change the crossover point for your specific wideband.

http://www.ecmtuning.com/wiki/v3narrowbandsim?s[]=narrowband&s[]=simulation

I'm gonna quintuple check for exhaust leaks but if that appears good I'll probably do that. Why does the narrowband sim get around it?

 

[lasthope05]

The basic function of narrowband is to oscillate stoic at idle and cruise conditions during closed loop. Narrowband sim basically allows you to change that factory stoic value to whatever you want.

 

[bmxfelon420]

Ah I didnt quite understand how it worked. So I just need to log the actual voltage of the sensor at the AFR I want and change the switchover to that point?

 

[lasthope05]

Essentially, yes.

 

[bmxfelon420]

That worked perfectly, basically by enabling narrowband sim and tweaking the value you can pretty much set it to whatever you want. I'm probably gonna tweak the transition area on the OL table though so that it doesnt buck going into OL. How much additional timing is a reasonable starting point for e85? I'm using the ECMlink modified Evo 8 table as my base. I've made a few slight tweaks to it but nothing major, just a slight amount of richening when my car spools because it spools a bit faster than a 2.0