Rep Power: 0

Hi Guys,

I have a 2004 Acura EL 1.7 - (Canada)
Its pretty much same as EX or SI

Some history behind my Primary O2:

End of 2013 I started getting:
P0134: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

Feb 2014
Original sensor was Denso - I replaced it with Bosch 15473 AFR sensor.
This new sensor was better than the old one but I continued to get intermittent codes for the o2, dont remember the code but might have been what I had in August(see below)

I believe during summer months it cleared up.

August/Sept 2014, started getting codes again
P0134: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
P1157 Air/Fuel Ratio (A/F) Sensor (Sensor 1) AFS Line High Voltage
P1157 Air/Fuel Ratio (A/F) Sensor (Sensor 1) Circuit High Voltage
P1157 Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem

Next few months I idn't drive it much because I had another issue which required ECU replacement

Jan 2015
Now my car has a Civic SI ECU (same part number as EL)
P2A00 - Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem
Looking at the readings, I see the primary afr generally at aprox 1 as read on obdII

Air–fuel equivalence ratio, λ (lambda), is the ratio of actual AFR to stoichiometry for a given mixture. λ= 1.0 is at stoichiometry, rich mixtures λ < 1.0, and lean mixtures λ > 1.0

My secondary O2 (non lambda) is hovering around 0.9 to 1.2 (I didnt know it was capable of going above 1V) which indicates Rich mixture

If suddenly let go of the throttle, I see Primary sensor jump to λ= 2 and secondary drop to 0.1V, and then gradually they steeped back to λ= 1 and around 1V respectively.

Gas milage has gone down the drain as well. 10kmpl = 23.53 mpg
I think short term and long term fuel trims were low single digit, Ill have to check that again to confirm


The 01-05 civic manual doesnt talk about AFR sensor so didnt know how to do much troubleshooting

I traced the wires to ECU. This is what the underhood male connector, looking at male pins looks like.

***
******
A22 A1
A6 A16
*******

Not sure what each wire is used for...
A22 - White -
A1 - Green -
A6 - Red -
A16 - Red/Yel -

A22 x A1 - aprox 2-3ohms
A6 x A16 - no continuity


I guess my first mistake was putting in a bosh instead of a denso.... And I'm guessing you guys are going to suggest I just change my primary o2 with a denso...

I feel like I should be able to throw in a resistor somewhere and make it better. Your thoughts?

Thanks in advance

 
Rep Power: 518

Mistake #1.

Duh.

Nope.

Buy the correct part. Install. Enjoy.