Fluctuating air fuel Ratio, help me!!

[kouki_hmongster]

Okay i'm having problems with my afr. installed my innovate wideband lc-1/xd-6 kit, calibrated the damn thing and got some readings. at idle sometimes it idle good then sometimes it idles around 18-20. as soon as i take out for a drive while cruisin afr is high 14 to low 15. as soon as i give it some gas the afr goes rich to 12-13, never consistant.

plus i have a O2sensor that is less than 3k miles.

Here's my set-up:

Ka24de N/A at the moment to break-in motor, arias piston, eagle rod, 740cc nismo, z32 maf, nismo fpr, bc cams/springs.......etc.....

all parts were bought brand new.

ECU is enthalpy, tuned for T25 and all the rest of stuff i stated.

Today I installed my afcneo to try and fix this problem, but seems like it was acting up a little weird, hotwire is set at 2in2out since ecu was tuned for z32 maf. i'm planning to hit the dyno for a fine tune, but want to know if this is ecu related stuff.

THis is pissing me off and makes me want to save up for full standalone.

thanks in advance,

[DevilMB3017]

The ECU is probably expecting a lot more air then its getting at those load levels if you don't have your turbo installed.

The idle is kind of okay because of that, but your going to be dumping a lot of fuel compared to the air your pushing into the motor.

Until you have your whole car finished and running right, I wouldn't really get on it too much. Check you don't have any fuel in your oil and if you are throwing any codes.

[Logan76]

I was thinking with 740's and a tune expecting boost, you may be washing out your cyl. wall's, I would do an oil change and put your turbo kit on.

[480sx]

If your idle was really between 18-20 you would hear your motor start to run like crap. Is that happening?

Your cruising AFR's are fine.

Your WOT AFR's *MIGHT* be an issue, how much of a fluctuation are you having? If your only talking .1-.3 difference, you probably dont have much of an issue. If its much more than that, i would start looking at your fueling system.

ECU is not the problem.

[240sxvaj]

Modified by 240sxvaj at 9:33 PM 3/29/2009

[kouki_hmongster]

The ECU is probably expecting a lot more air then its getting at those load levels if you don't have your turbo installed.

The idle is kind of okay because of that, but your going to be dumping a lot of fuel compared to the air your pushing into the motor.

Until you have your whole car finished and running right, I wouldn't really get on it too much. Check you don't have any fuel in your oil and if you are throwing any codes.

There isnt any fuel in oil, i already double check and made did oil change anytime i thought fuel was in the oil.and no engine check lights, but still need to manually check for any codes

If your idle was really between 18-20 you would hear your motor start to run like crap. Is that happening?Your cruising AFR's are fine.

Your WOT AFR's *MIGHT* be an issue, how much of a fluctuation are you having? If your only talking .1-.3 difference, you probably dont have much of an issue. If its much more than that, i would start looking at your fueling system.

ECU is not the problem.

around 18-20 the car idles fine but a very slightly rough compared to if it is around 14. but it doesnt sound like it wants to die.

actually i got the car dyno tuned on dynojet and it made about 130whp and 130wtq. Based on tailpipe afr readings it's in the steady 13's underload to redline the guys at the shop told me i am fine. so i'm guessing it's okay, but i still dont like the idle afr, sometimes it wants to idle around 14-16 for a long time then sometimes it goes rich around 12-13 and then 18-20. i dont know what the heck is causing this.

it seems like after reinstalling the afcneo, the idle drops like it wants to die and goes back up. but it only happens once in a while.