Hi fellas, just finally got the wideband (LC1) hooked up and took a test ride in my brothers car.. noticed some very strange things...

When it first starts its very lean at idle (maxes my WB gauge at 21.8) then as the car warms up it goes very rich, idles around 11-12:1 afr. I have the stock 02 sensor turned off in crome and I'm using the narrowband output of the LC1 to feed the ECU.

I've started with a stock P30 base, and had to add upwards of 25% more fuel just to get this thing to run/idle correctly. Is it normal to have to add that much fuel for a 12.5:1 motor?

Build isn't too radical IMO...

84mm Darton sleeved
RS Machine "R" pistons
Type R oem crank
Manley Turbotuff rods
cleaned up PR3-3 Head with crower valvetrain
Buddy Club Spec III cams
Blox intake manifold
4-2-1 header
stock 240cc injectors (for now)
Chipped P72 on crome

Any ideas?

How could I go from so lean to so rich? I'm sure its my tuning (or lack there of) but??

 

Are you able to datalog the sensors or just the AFRs? You need to be able to datalog before you try any more tuning...... What wideband O2 are you running?

You increased the displacement and raised the compression. The P30 ECU's fuel and ignition maps are meant for a B16 w/1595cc of displacement and a 10-10.5:1 compression ratio. Not a 1973cc, 12.5:1 compression ratio B18. Even a stock P73 basemap would have a hard time running that smoothly.