Kmanager show 10.7 A/F ratio, all other sensor work 100%

[poorteg]

When posting a KPro problem with your vehicle, please include:
- serial number of your K-Pro 00582
- KManager version (not 'the latest') 1.4.1.0 july 2010 Hardware: 1.00 Firmware: 1.00
- the calibration (as an attachment)
- a datalog of a problem (as an attachment)
- what sort of vehicle you have 93 Honda civic
- what sort of ECU you are using Prb ECU but does not have prb sticker so not 100% sure it a prb
- anything about the car which has been modified from stock which may affect the ECU (don't include what sort of rims you have nor stereo etc).
- a specific description of the problem

This is a k20z3 motor with a2 engine harness, eg/dc hybrid racing conversion harness.

The a/f in Kmanager just showed up as 10.7 with the car running and no changes meaning the ecu is not seeing the o2 sensor. I have verify that all the o2 wiring is 100% correct.

Here are some voltage reading at the ecu pins:

With the key on engine off, the voltage reading at the pcm pin connector are:

A6 (AFS (+)) Sensor input 2.1 V
A16 (AFS(-)) Sensor ground 1.8 V

With engine running, the reading at

A6 (AFS(+)) Sensor input 2 V
A16 (AFS (-)) Sensor ground reading changes vary from 1.5-2 V once started and settle to around .1 V idling.

According to the research i've done, honda o2 goes by current for the reading but according to the voltage reading. The ecu is varying the voltage reading when the car is running indicating that the o2 is working and it seeing the changes? but the reading doesn't show up in Kmanager?

I have ruled out the o2 as being bad because i tried a known working o2 and same result, im using 100% oem rsx-s primary off both 03 rsx-s.

Trying to figure this last problem out and the car is all set, everything else on the car is working, all other sensor are reading normally.

[poorteg]

If i measure the resistance between the two pin for the A/F sensor what kind of reading should i get? Green wire pin and White wire pin on oem-s sensor

[Spunkster]

The next step is to try your ECU on a known good vehicle and see if it reads correctly. If it does then you know there is a problem with the wiring in your vehicle.

[taitcw]

[Short]
2 wires are for sensor heater, resistance at room temp should be between 2.1 to 2.9ohms.


[Long]
Hey, I had O2 sensor problem on mine a month back.

I dont know whether it was a coincidence, but the A/F reading got stuck at 10.7 after I added JRSC. It flagged DTC P0135 (or P0134 cant remember exactly).

After I clear the fault code ("Clear DTC" from KManager), sensor would work again, but if engine idles for too long, sensor would stop working and flag the same fault code.

I dont know how the ECU read the sensor but I probed it before, ECU seems to PWM the sensor in some special ways and get a reading somehow?!?! Maybe Hondata can tell us more?

I probed the heater connections before, I believe, from a cold start, ECU will energise the heaters (put 12V across it), then slowly back down to 0V within a minute or so.

Anyway, my problem was all sorted by buying a brand new sensor from Honda :)


DT

[TodaCL7R]

hi, i have the same problem & wondering if there is a solution to this. btw, i bought a brand new D17 wideband sensor. thanks

[wwautotechnic]

hi, i have the same problem & wondering if there is a solution to this. btw, i bought a brand new D17 wideband sensor. thanks

Problem solved!!
Congratulation MR TodaCL7R! :P

[Alexx]

A nice post with lot of information. Thanks for sharing.