Lean cruise running rich

[limited cv8r]

I thought lean cruise was a good thing until I hooked my W/B up again the other day. The leaner the commanded AFR goes the richer my W/B shows. Both commanded and measured AFR's are both around 14.7 most of the time,but as the AFR leans off for lean cruise up to about 16:1 my W/B richens up to about 13.5:1. I was running COS1 in closed loop with maff dissabled. Do you need to enable the maff for lean cruise? Maybe one of you guys can enlighten me. Apart from that everything else is fine. I,ve included a screen shot of one point where it is occuring.
cheers :help2:

[kbracing96]

Probable because your VE table is not tuned properly. You need to have it correct, or it will not give you accurate fueling when not commanding 14.63

[limited cv8r]

VE table is good, done with AUTOTUNE. Comanded and measured AFR's are usually pretty close most of the time, it is only when it enters lean cruise that the AFR's go out of whack.

[joecar]

COT protection...?

[ringram]

Did you alter the default lean cruise values?

[limited cv8r]

COT (catalytic overtemp) is disabled. Standard lean cruise settings. No wonder my fuel consumption is crap,thought I was cruising at 16:1 not 13.5:1. Does using the custom operating systems affect this at all.

[GMPX]

No it doesn't, can you please post a screen shot of the Lean Cruise table.

Cheers,
Ross

[limited cv8r]

here's the lean cruise table.

[Extinct]

Wow, need a little higher res shot than that, I can barely read it.

[limited cv8r]

hope this is better

[GMPX]

I have to say :nixweiss: , that is bizarre.

Just looking at the log though, the AFR's don't seem to track very well unless the O2's are cycling, look at the area where it just comes out of Lean Cruise, the commanded appears to go to 14.63, yet the AFR is still way rich until the O2's start cycling.

Cheers,
Ross

[limited cv8r]

As your reply states GMPX the AFR tracks 14.63 pretty well when the 02's are cycling as shown in untitled pic, you can then see it go into lean cruise in the second pic untitled 2. Am I right in assuming that it does not use the 02's in lean cruise as the scan tool show fuel trims at "0" when it cuts in. If this is so then where does it get the information to command the cruise afr

[SSpdDmon]

I wonder if it's an error in EFILive? The description says the value in the cell will be ADDED to the commanded stoich. If he's using EQ, it needs to be subtracted, not added. However, if he was using AFR instead of EQ, adding the values to the commanded stoich would work. It would explain why his WBO2 reads a richer number when lean cruise hits. Does this make sense?

[Tydriver]

Any updates on this ? Just curious..

[limited cv8r]

After a bit of trial and error and trying several diferent tunes in the car I have come to the conclussion that you need to have the MAF enabled for lean cruise to work. No matter what tune or configeration I flashed in, as long as the maf was dissabled lean cruise did not work. With the maf enabled and dialed in using the BEN factor lean cruise is spot on. Also on a side note, after dialing in the maf table and leaving the car in open loop I am suprised as to how well the commanded and actual AFR's track each other. perfect except for a slight discrepency during throttle transitions. I am very tempted to leave the car in open loop with maf dialed in due to the accuracy of commanded V actual AFR's all of the time. :notacrook: