AFR table

[nickw14]

Here is a log that I took about a week ago: http://datazap.me/u/nwilging/gfy?log=0&data=1-9

I noticed that at 0% throttle, and at idle, my AFR goes up to 20. This seemed strange, so I started looking around the tables to see where it is getting this value from. Well, I can't find it anywhere....

The closest thing I can find is Fueling Primary Open Loop\Primary Open Loop Fueling table. However, idle values in this table are the normal 14.7. Where does the AFR for closed loop come from? Or is there just a corrections table that uses the values from the open loop afr table?

Thanks for the help.

[Kodename47]

It should only show 20 when there is no fuel being injected, like on the overrun. Idle should still be around 14.7.

Open loop fueling is just the open loop commanded AFR, there are 2 closed loop compensation tables.

[Toyota John]

I don't think the table to adjust overrun fuel cut has been defined yet.

[nickw14]

I haven't seen a table that looks like overrun fuel cut. Although I haven't really been looking either.

Right now I am trying to decipher these "conversion factors" between the OL afr table and the CL compensation tables... They're all negative numbers...

[PantsDants]

Originally Posted by nickw14

I haven't seen a table that looks like overrun fuel cut. Although I haven't really been looking either.

Right now I am trying to decipher these "conversion factors" between the OL afr table and the CL compensation tables... They're all negative numbers...

In RomRaider, for a given load/rpm cell, you add the value to stoichiometric (14.7) to get your targeted AFR. For example, say a cell is at -1.0, then you'd have:

14.7 stoichiometric + (-1.0 compensation) = 13.7 target AFR

There are other, undefined compensations in the ROM as well, but this is roughly how the ECU gets what AFR to target in closed loop. Also note that lean adjustment (that is, positive numbers in your table) won't do anything; you can't target anything leaner than 14.7 using the load compensation tables.

[nickw14]

Originally Posted by PantsDants

In RomRaider, for a given load/rpm cell, you add the value to stoichiometric (14.7) to get your targeted AFR. For example, say a cell is at -1.0, then you'd have:

14.7 stoichiometric + (-1.0 compensation) = 13.7 target AFR

There are other, undefined compensations in the ROM as well, but this is roughly how the ECU gets what AFR to target in closed loop. Also note that lean adjustment (that is, positive numbers in your table) won't do anything; you can't target anything leaner than 14.7 using the load compensation tables.

Well that's what I thought at first, but then I compared those values to the actual AFR. Which brings me back to the original post: under certain driving conditions AFR leans out to 20.

What you're saying makes way more sense though. I suppose it could be yet another table that holds the values or compensation values to lean the afr out that much...

[Kodename47]

Originally Posted by nickw14

Well that's what I thought at first, but then I compared those values to the actual AFR. Which brings me back to the original post: under certain driving conditions AFR leans out to 20.

What you're saying makes way more sense though. I suppose it could be yet another table that holds the values or compensation values to lean the afr out that much...

Can you post a log or explain exactly when you're going to an AFR when there is no fuel being injected? It should only show 20:1 when you come off the throttle. If it's when you step on the throttle something is very wrong and you'd feel it as it would hesitate. There would be absolutely no power being made. There are no tables that would allow it to go that lean.

[nickw14]

Originally Posted by Kodename47

Can you post a log or explain exactly when you're going to an AFR when there is no fuel being injected? It should only show 20:1 when you come off the throttle. If it's when you step on the throttle something is very wrong and you'd feel it as it would hesitate. There would be absolutely no power being made. There are no tables that would allow it to go that lean.

I only noticed it when I looked at the logs in the first place, so I haven't went back out to test when it is 20:1. You are correct, when I am off the throttle the AFR does jump up, but it also does this at idle. Any time I am on the throttle it does not appear to be abnormal.

I guess I am confused as to where it's finding these values.

Is no fuel being injected even on deceleration?

[Koa]

Originally Posted by nickw14

I only noticed it when I looked at the logs in the first place, so I haven't went back out to test when it is 20:1. You are correct, when I am off the throttle the AFR does jump up, but it also does this at idle. Any time I am on the throttle it does not appear to be abnormal.

I guess I am confused as to where it's finding these values.

Is no fuel being injected even on deceleration?

not sure if it's a hard fuel cut or significantly pulled back (I'm leaning towards the latter). Kode or someone else will chime in with a definite answer. Here's a few threads to help glean an understanding of what goes on during deceleration in gear

http://www.bobistheoilguy.com/forums...Number=2876999

http://ecomodder.com/forum/showthrea...off-22374.html

http://www.city-data.com/forum/autom...-coasting.html

[Kodename47]

It shouldn't do it at idle, but yes the fuel injectors shut off on overrun/deceleration.