JJ63

iTrader: (1)

I have a 400ci with a miniram. I have a NB o2 on the drivers side and a WB on the passenger side. At cruising speeds the left bank reads slightly rich 124-126 while the wb reads 17-20afr. At idle I get 128 while the afr is 12-13. WOT is the only place everything lines up 12.5 for WB while the NB o2 reads in the 880 range. I've checked the plugs, fuel pressure, Spark plug wires no fuel leaks anymore. What else is there to check? It's like the two sensors go opposite of each other until wot.

ULTM8Z

You can't really compare BLM to AFR. BLMs are not an indicator of absolute AFR.

Also, 124-126 doesn't mean it's running rich. It means the ECM has been pulling fuel out to prevent the engine from running rich.

Minirams are notorious for low speed fuel distribution issues... both side to side and front to rear. I went to great lengths to eliminate that.

Side to side... https://www.thirdgen.org/forums/diy-...ram-split.html (ignore the external air tube part of this with that muffler thing... I've since changed to something much more simple... but the modifications to the manifold are still in place and working great after all these years).

Front to rear.... https://www.thirdgen.org/forums/diy-...injectors.html


What has been done to your calibration so far?

JJ63

iTrader: (1)

Thanks for the quick response. I'm basically using your minram bin, with different ve and spark table of course. I have 35.5lb injectors in the front 4 injectors and 32's in the rear. Maybe it's too big a difference? At times the blm do dip down to 114 while wb goes way lean. I assume since the ecm is pulling fuel, it's causing the lean condition on the passenger side.

ULTM8Z

35 to 32 isn't too big IMO.

But yeah, pulling fuel on one side can cause the other side to run lean.

You could potentially richen up the O2 thresholds as well particularly at higher maps. I did that and the Miniram seemed to like it.

ULTM8Z

Btw... curious if you noticed any improvement with the bigger injectors up front?

JJ63

iTrader: (1)

I just got thru changing everything back 35lbs. It runs like it should. The Wb stays around 14-16 while the blm's are moving all over. An injector must have been bad at times.