GA16DE air fuel ratio

dave_f · Jan 11th, 2003, 04:55 PM

does anyone know the typical air fuel ratio of a properly running stock ga16de? I have my wideband O2 sensor hooked up and am trying to determine if my car is running too lean or if the is a O2 sensor is not calibrated correctly.
-dave

Teknokid · Jan 11th, 2003, 09:02 PM

i heard the optimum ratio was 12 to 1 or around that number. Do not quote me though. Check sentra.net I think that is where i remember that number from

dave_f · Jan 12th, 2003, 11:22 AM

I was interested in the stock a/f ratio that Nissan programs to at the factory. I remember reading somewhere that Mike K. said that Nissans run typically on the rich side, but after putting in my wide band and driving around for a while my car runs around 16.0 a/f (lean). I don't know if its because Nissan was trying to tune the ga16de for fuel economy or if there is something wrong with my car (I get about 40 mpg... 192 Sentra E stripy with a 5 speed). I would like to figure out if there is anything wrong before I start to modify the fuel delivery system. I have never sensed any detonation, and under load and the a/f ratio does richen up under load (13.8) I have the 370cc injectors, walbro pump, electronics, and the bigger MAF ready to install... I'm trying to make sure everything is running correctly before I slap them on.
-dave

sunnysentra · Jan 12th, 2003, 11:49 PM

At idle after a good run, my A/F ratio is lean and toggles between the stoichiometric mixture steady and not rapid. At 3000 rpm, the things go rich/lean/rich lean back and forth. If you read a Nissan consult, this reads rich/lean/rich/lean. It richens full at WOT on the meter. I am having the consult run while I drive sometime to check things out, I will let you know what the A/F ratio is. Also check the factory manual for readings.
CD

javierb14 · Jan 13th, 2003, 12:09 AM

what kind of wideband unit are u using?

dave_f · Jan 13th, 2003, 07:32 AM

I'm using a lambda boy wide band kit. It uses a NTK 5 wire wide band sensor and has a EGO output which I am feeding to my ecu, so it thinks I have the stock sensor in place.
-dave

javierb14 · Jan 13th, 2003, 04:39 PM

i have the techedge wideband unit. i need to get a new NTK sensor, mine has 300K+ miles on it

dave_f · Jan 13th, 2003, 05:29 PM

did you ever get a chance to run your wide band in your car with the stock ecu and before any mods?
-dave

javierb14 · Jan 13th, 2003, 06:18 PM

nope, but technokid has a dyno plot on here with an A/F curve.
http://www.nissanforums.com/showthre...threadid=12822

if he has the dyno data on file, you might be able to plot it.

dave_f · Jan 13th, 2003, 09:24 PM

thanks, but I was wondering about the closed loop part throttle air fuel ratio. Once I floor it, the acceleration enrichment kick s in everything is fine (runs a little rich), its just highway cruising under light load the engine really starts to lean out. I figured it was a fuel economy thing, but I was wondering if anyone else has experienced this.
-dave