I have just installed a wide band 02 sensor and are getting very high AFR readings at idle. I am thinking that the readings are faulty at idle. Is this what other people see?
No, shouldn't be. What wide band do you have? Edit: From memory, the one I was looking at has to be calibrated before use. I think it was an open air calibration but I could be wrong. Have you done this?
I have the "Tech Edge WBo2 2J1" which comes with a Bosch "LSU 4.2 7200" sensor. There is a calibration function on this unit but it is "shipped calibrated" so I didn't calibrate it. The AFR readings are sensible during all other driving conditions tested so far.
Youtube video showing operation at idle here. Seems to read ok? What kind of readings are you getting at idle?
The reading is about 18-19 at idle and about 13-15 upon driving. The engine management is Apexi Power FC. The O2 feedback is off since the last dyno tune and a lot has changed since then.
Yes dyno time is close. If the AFR readings are correct I can make some adjustments. Before I put the car on a dyno again I need to do a couple things including comission the VCT and EBC. Most of the hardware is installed for these functions so the hard work is done.
In stock form afr at idle is about 12-13, does yours idle smooth? i found anything over 14 and it starts to get rough. Also pull your sensor out and measure the air to be 20.9, if it is it's working.
You need to add fuel..... You are way too lean. Idle should be stoich and WOT should be no more than 11.5-12. I'm not familiar with the Apexi system so I can't help you with specifics, but you need to increase your K value and injector void to add some fuel to all that air you are pumping in there This is assuming your WB is reading correctly.
??????? Idle at 12-13afr? That's a negative mate. Idle and cruising should be stoichometric (14.7:1AFR). The ECU uses the closed loop section of the fuel map which relys heavily on the O2 sensors to determin the correct AFR. AFR at wide open throttle depends on the tune. A stock tune can go all the way down into the 10:1AFR. Your tuner should target around 11.5:1 - 12.5:1 for a street driven turbo vehicle (obviously depending on boost and timing). Have you got bigger injectors by any chance? I would not worry about idle being lean, it's cruise and WOT that needs to be correct. Have you held the throttle at around 2000rpm in neutral and see if the AFR hangs around stoich?
Incorrect..... Idle should be close to stoich, but cruise AFR's can be leaned out quite a bit. Mr Nissan's maps run up to 7% lean on light load and his maps are very conservative. The ECU doesn't monitor the O2 sensors at idle, so they play no part in idle afr's. Idle mixture at normal operating temp is determined by injector values. You DO have to worry about being lean at idle, your k value/void are constants. If your injectors are not providing enough fuel at idle, they will not be providing enough fuel throughout the rev range. If you are lean at idle but have correct afr's at WOT, your maps are too rich in the high load region (which compensates for the injectors running lean).
as far as i can tell my 89 model doesn't use the o2's at idle. And with stock map installed it idles at about 12.5:1, using an LC-1 5 wire wideband to measure it. Should also mention no boost leaks, injectors tested and cleaned recently, and motor was also refreshed recently and running perfect.
Thanks for the input on this one guys. I was able to correct the AFR at idle using the Apexi hand controller. Here I adjusted the MAF curve in the low voltage area.
you would be able to use two wide bands if there is an output for a narrow band sensor (i.e. a connection that simulates a narrow band), that you would feed to the ECU.
The PEX-ZED has 2 sets. I guess the number of gauges/sensors you use depends on how your exhaust is set up and where you want to locate the sensor(s)
