AFR goes lean when accelerating, only on closed loop *pics*

[jamesfawcett]

hi everyone,

The problem is, when idling, afr is fine, or when cruising at 40mph/80mph etc afr is fine, but when accelerating from idle up to speed, it goes really lean.
My car was rolling road tuned this week, Open loop works perfect, just a little rich when cruising, but neither i or the tuner could sort out a problem when on closed loop.

The reason i want openloop to work is because at idle and when cruising along, my afr is a little rich, and for fuel economy reasons.

Here is a screenshot of my closed loop settings:



and here is a screenshot of my low speed fuel table settings:




please let me know if you see anything out of the ordinary im really stuck at what to try, ive tried loads of different closed loop settigs but get the same effect when accelerating

thank you for any help you can give me

[jamesfawcett]

oh and heres a copy of my power output

[Spunkster]

http://www.hondata.com/forum/viewtopic.php?f=19&t=3772

[jamesfawcett]

very sorry i forgot to include my map and details:

engine: B18c4 440cc injectors turbo 10psi
ecu: hondata with S300
vehicle:


datalog and map attached :)

thanks
james

[crucian]

James, if you are concerned about the car running a little rich while idling and cruising, why don't you just street tune it in open loop and leave it? Every car I've ever tuned stays in open loop and have great gas mileage.

[jamesfawcett]

Hey, thank you for the reply.
I don't feel comfortable tuning it myself, I would love to be able to but i don't feel confident enough yet,

I drove it today to north Yorkshire and have just worked out I got about 10mpg it was very rich

I think your right, I need to get the fueling tuned to run open loop.
Can I just ask one question, if I reduce the fuel for a certain point on the map, does my timing stay the same? If I reduce the fuel values to get to arroound 14.7 afr, will I be safe with the same timing?



Im driving it to germany to the nurburgring in about 8 weeks time I'd like it sorted by then

[crucian]

The timing will not change if you adjust your fuel table. Have someone drive while you adjust the fuel tables in vacuum while cruising. Getting your AFRs perfect while cruising takes some time. But when complete, your car will drive like a charm.

[jamesfawcett]

The timing will not change if you adjust your fuel table. Have someone drive while you adjust the fuel tables in vacuum while cruising. Getting your AFRs perfect while cruising takes some time. But when complete, your car will drive like a charm.

thank you ok thats great, the fuel tables i have from them are not even, is this normal?:




the one on the left is my original fuel table which worked really well in closed loop the car drove well.
the one on the right is how it is now from the tuners, running rich when you decelerate, running lean when you accelerate, and closed loop doesnt work,
ill have a go this week with a friend :) is it normal for fuel tables to be this uneven?

thanks
james

[crucian]

The timing will not change if you adjust your fuel table. Have someone drive while you adjust the fuel tables in vacuum while cruising. Getting your AFRs perfect while cruising takes some time. But when complete, your car will drive like a charm.

thank you ok thats great, the fuel tables i have from them are not even, is this normal?:


the one on the left is my original fuel table which worked really well in closed loop the car drove well.
the one on the right is how it is now from the tuners, running rich when you decelerate, running lean when you accelerate, and closed loop doesnt work,
ill have a go this week with a friend :) is it normal for fuel tables to be this uneven?

thanks
james

The one on the right shouldn't look like that. You will get abnormal AFR readings while cruising. It should look something like this.

[jamesfawcett]

hi Crucian,

ive been tuning for about 10 hours in total now, and i dont know if im getting anywhere...

this is how my fuel map looks now...



The values keep leading me to make adjustments that make the graph more and more that shape,
they dont run parralel like the lines on your graph at all, do you know where im going wrong?
the afr seems good when accelerating in the range if tuned, but does this look massivly wrong so far?

than kyou
james

[crucian]

hi Crucian,

ive been tuning for about 10 hours in total now, and i dont know if im getting anywhere...

this is how my fuel map looks now...



The values keep leading me to make adjustments that make the graph more and more that shape,
they dont run parralel like the lines on your graph at all, do you know where im going wrong?
the afr seems good when accelerating in the range if tuned, but does this look massivly wrong so far?

than kyou
james

Yes that's way off James. Your goal is to get all those percentages to 0%. Go back to the original graphs that you posted. Highlight an entire column, right click and then press the word interpolate. Do that for each column in your cruising area. When tuning, look at what TWO columns your engine is running in at the time. Highlight the entire TWO columns and select plus or minus to get closer your target AFR. Now that you've got you AFRs close enough to your target AFR in those 2 columns, make minor adjustments in each cell. By the time you're done, your graph should look like the one I posted. I hope you understand what I'm trying to say. :-)

[crucian]

I forgot to add, if 2 adjacent columns have percentages that are broadly separated, adjust only one column to get it closer to the other. For instance, one column is closer to an average of 0% and the other has an average of 21%, subtract fuel from the 21% average column. Each time you make changes, clear the "estimated fuel change" field. Then start driving again and select both columns accordingly. I know it sounds confusing, but this is the only way I can explain it.

[jamesfawcett]

thanks!!! and that makes complete sense,
i understand now, and i wasnt aware of the interpolate function either, im going to try that out :)

ill go to my old map and have another go later on today, and thanks for the tip about working on two columns at once too


hopefully ill get there one day :P

[Will_B18C]

The timing will not change if you adjust your fuel table. Have someone drive while you adjust the fuel tables in vacuum while cruising. Getting your AFRs perfect while cruising takes some time. But when complete, your car will drive like a charm.

thank you ok thats great, the fuel tables i have from them are not even, is this normal?:




the one on the left is my original fuel table which worked really well in closed loop the car drove well.
the one on the right is how it is now from the tuners, running rich when you decelerate, running lean when you accelerate, and closed loop doesnt work,
ill have a go this week with a friend :) is it normal for fuel tables to be this uneven?

thanks
james

I assuming that u are using a wide-band AFR for your road tune :)
Just to share some stuff I pick up from using the S300.

1) Target Lambda target is not useful for tuning. This is because when u throttle off, the reading of the AFR are taken in account, resulting in inaccurate output.
What I do is that I hold the throttle at a constant position untill the AFR reading does not fluctuate much, take note of the AFR, RPM and MAP senor reading. Then adjust the values of the cell and cells around it.

2) Another thing to do for tuning in close loop is to change the short term fuel trim adjustment to 0% for both min and max before tuning. Once u r done w tuning, revert back to the original settings. This is to prevent the ecu from interfering adjusting the fuel during your tune. (Do remember to reset the ECU before tuning to remove any long term trim adjustment)

(There are too many variables in open loop tuning which need adjustments. eg. ECT, IAT, fuel and ignition compensation. Keep it simple by tuning in close loop with above settings)

love the mini with the boosted B engine. Should be fantastic fun!

[Will_B18C]

btw what is the maximum boost u are going. This is because ur map is only tune up to 11.9 psi, any boost beyond that will cause your engine to misbehave. Do check your ignition setting, looks strange to me.