I know this has been beat to death, but cant seem to find a strait answer.

I am getting code 0115 (Bank 1 too Lean)

So far I have...
1. Replaced the aftermarket intake with the stock one. (there was a hole in the aftermarket one the size of my thumb)
2. Cleaned the MAF and TB.
3. Replaced the spark plugs. (the back 3 were black)
4. Replaced the fuel filter.
5. Sprayed starter fluid around to check for vaccume leaks.
6. Tested the MAF sensor. (tested good)
7. Replaced all 3 intake gaskets.


Also just found out I have California Emmisions, and have no clue what that means to me...

Thank you for being patient, and for all your help over the years with my MAX!!!

Dave

 

Your sensor is fine. Your rear bank is running lean due to a vacuum leak or fuel delivery problem.

 

It is definatly running lean. I replaced my plugs and the 3 in the back were all fowled out.

I also just last week took off the aftermarket intake and went back to stock, after finding a huge hole in the side of it where it went through the fire wall into the fender. it was filthy. I took everything apart and cleaned it all out. (had the code before this)

where should I start to diagnose this?

Are there any tests I can do to rule some of these things out?

 

A lean code doesn't really point to the o2 being at fault, but rather something causing the lean condition such as a leak in the intake or lack of fuel.

Lean doesn't fowl out your plugs, it burns them up.
What color was the electrode?

That could have been causing the issue. Did you clear the code after you put the stock intake back in place? I'd start by doing that and see if the code comes back.

 

The plugs were black.

and yeah I cleared the codes. It came back about 35 miles later. then I took it all apart and cleaned all the way up to the engine, and cleared again and it came back fter 40 miles or so...

 

I'm thinking injectors or LIM gaskets. Something only affecting those three.

 

Could also be a leaking vacuum line sourced close to a rear intake runner.

 

Replaced the Fuel Filter, and reset codes. Will drive a bit and see what happens. Gonna consider leaks next i guess.

Is there a way to test or override the O2 Sensor or MAF Sensor? Am thinking somthing like the Resistor fix for the Knock Sensor to atleast get it to pass NY Inspection. LOL

 

I just tested my MAF sensor a few hours ago using datascan via the consult interface.

With a warm engine placed in neutral these are the voltage ranges:

IDLE 1V - 1.7V

2500RPM 1.5V - 2.1V


You'll need to tap into the white wire on the MAF connector and measure with a multimeter.

 

This wont help your lean condition, everything needs to work correctly to control the A/F ratio and pass emissions.

 

Fuel Filter didnt Fix it. I will check the MAF tonight, and then I guess I am at a point where I have to smoke the intake system. any other suggestions before I spend that $100?

Any way to test the O2 sensor?

 

I tested them with Datascan yesterday. Holding the RPM at 2200rpm while in closed loop mode the LEAN and RICH signals on the screen changed 9 times within 10 seconds. That indicates the upstream O2 sensors kept the fuel mixture correct. If the sensors weren't working correctly then it would of stayed on either RICH or LEAN within that short period.

You need SW and a Nissan Consult Interface to reach the ECU.

The voltages on those O2 sensors are always oscillating from 10 to 90 so there's no way of testing them manually.

 

Spray Carb cleaner around the area of the manifold. Leaky valve covers will also cause a lean condition via the PCV system. Have you done a visual inspection of your vacation hoses and intake ducting?

 

Idle 1.4 ish
2500 rpm 1.9ish

No access to that without paying the dealership likely. Any other test?

I used starter fluid to do this last week, and didn't notice any change in rpms as I sprayed it.
Am thinking of just replacing the $25 gasket, but would like a confirmation before doing all that work.

 

so do I replace the O2 sensor? or fog the intake system?

 

If you didn't get this code until after you reinstalled the OEM UIM then you should try remounting it again. Since you're only getting the lean code on bank 1 I would also remount the LIM.

 

Just replaced all 3 intake gaskets, and the code came back again after 40 miles. I am running out of ideas.

I am updating the OP with all I have done to date.

 

I would start a new thread titled "bank 1 lean". IT IS NOT YOUR O2 SENSOR. YOU WOULD HAVE A DIFFERENT CODE ALTOGETHER.