I PM'd the experts about this already (sparks03max and NmexMAX) but I thought I would post in here in case anyone else has any relevant information...

I just got my wideband installed and got the gauge run. Wired it to my cigarette lighter. My car was tuned at a local shop around here but I was never fully happy with it and with wanting to do a BBMAF soon, I needed to get a WB.

So I was monitoring the gauge for a little bit today and at part throttle, it runs decently rich. I saw 11s to 13s AFR. Now, I do have 350Z injectors and it is my understanding the ECU is supposed to compensate for the larger injectors on its own. It seems like it's not doing that, so I am taking out about 8% fuel @ 2k RPMs, 10% @ 2.5k, and about 13% @ 3k (haven't touched anything above that yet)

Now, my AFR is high 13s to mid 14s - I still have some fine-tuning to do but it's much better then it was. Gas mileage seems to be improved as well. One odd thing that happened was I shut the car off after setting the fuel values, I restarted it about 30 mins later and with those same values, the car was running lean for like 5 mins (15-16.5 AFR) and I added more fuel, the AFR was 14.7 or lower, and it continued to richen up to about 12s where they were before so I put my values back in to lean it out to 13s-14s. It seems like the car shouldn't do that... I don't know if the car does run a little lean when you fire it up (I always thought it ran rich) or if it was just a fluke or what. I am at work now, so I won't be firing up the car til tonight.

Should I not worry that it reads lean when I first start driving it since it doesn't show lean when I tuned it? The only other thing I thought was maybe my settings are incorrect on my NEO. I changed it into Pro mode so it wipes all your values (which I saved) but I did that because it allows more control of tuning at more RPMs. It shouldn't have touched the car configuration or anything but my settings are:

1 IN/ 1 OUT
6 cyl
For sensor, I believe "hot wire" is selected. Whatever the first thing in the list is what is selected
And the arrow points to in between 1 and 2 o'clock.

If anyone has any feedback that would be wonderful. I just want to make sure I don't blow the motor from the WB reading wrong or something haha I heard that sometimes the WB is inaccurate if you don't have a good ground but I would assume the ground for the lighter is good enough? And according to AEM, the WB doesn't need to be calibrated so the bung was welded after the y-pipe (no cats on my car) and installed.

 

Sounds like your O2 sensors for the rich issue. Let it warm up and see what it does.

Check fro codes too. Mine does the same but you all know my O2 set-up (secondaries plugged into the primary port )

So in closed loop/open loop control it runs a bit rich sometimes.

 

My o2's have had codes for a while ever since the headers. I'm about to pass out for bed now but I made a thread about it a little bit ago and it had my codes in it. Yeah its weird cause I can leave it on cruise and watch the afr go from 13.1 to 16.7 and back and forth all on its own. Guess it really is time for new 02's...

 

So where is the vacuum hose that runs from the back of the motor into the intake?? I didn't see it. Well, I probably looked right at it haha but nothing looked like it to me. Anyone have a picture?

 

You shouldn't be concerned with your AFR's in respect to tuning until after the car is fully warmed up. Also, you weren't specific about which AFR's you were experiencing at what RPM and load. Are you talking about Idle, wot, light load, etc? These are all necessary details.

 

You should only be concerned about WOT! Idle, Cruise, and all part throttle conditions are under control by the ECU.....

 

That's not true. Yes they're controlled by the ECU but that doesn't mean that they might not need to be adjusted. Once you change injectors, MAF, etc the entire load scale is different.

 

I only tune when the car is warmed up, but I'm saying that sometimes after it is warmed up, it runs lean randomly and then randomly doesn't at all RPM levels. I think it might have to do with me having an intake and the PCV vacuum hose is still attached to the intake manifold. Maybe it could also be my o2's?

Yeah, I needed to take out alot of fuel at low throttle. As much as 12% with the Z injectors.

 

You could be experiencing some difference in MAF readings from air turbulence. My Z does this too sometimes and I haven't quite pinpointed the problem. Remember the ECU will adjust timing based off AIT's as well so if the temperatures drop or raise suddenly the timing will change thus causing a change in AFR's.

 

I have a larger MAF, Z33 injectors, and mine runs and idles fine, WOT & otehrwise, aside from my closed loop/open loop switchover hiccup (~1500 depending on load).

I did find that my PCV plays a huge role in idle AFR. I had a breather connected and that was no good, I needed to add 12% @ idle. Now with the PCV connected, no adjustments whatsoever are needed (14.7).



I say it's your O2 sensors like I did earlier in this thread because mine fluctuate slightly, but not as "drastic" (big word for the description +/- 2.0 AFR) but my AFR's rarely go over 15.0 under load, light or high (unless I'm completely off the throttle).

One thing that I've noted over the years and repeated numerous times is that the ECU compensates for the Z injectors just fine. Like i said, mine idles fine, etc. The one item i notice is that my dash MPG's are higher as well as my STFT's because the ECU is taking more fuel out, therefore it thinks I'm getting better MPG.