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VTECANDY
14-12-2011, 09:29 PM
Hi all,

got a imported prelude, bb1 si-vtec h22, just replaced the o2 sensor with a bosch 4-wire equivalent.

Not sure if the guy wired it up properly as he told me that I had an aftermarket O2 sensor originally so it wasnt a direct plug up.

I had tried to re-wire it today by using a multimeter to determine which pin connectors on the car's o2 wiring harness connecter were:

* the heater voltage supply ( as indicated by the same voltage as the car battery), * the sensor signal wire, which has a voltage of 0.5v
* heater ground which has minimal resistance to vehicle ground
and the ECU ground reference as determined by the pin with the highest resistance to the vehicle ground (all this was suggested in the bosch 02 sensor catologue if the wiring pattern was unknown for the vehicle).

I had turned on the car, the check engine light (CEL) came on immediately. So i have rewired it back to what the guy initially wired it up as. The CEL comes on when i floor it and the car reaches speeds of between 80-100, if I nurse it up to 100, it doesnt come on. However, in the mornings, idle fluctuates and back fires once warmed up for a few minutes and feels like there is no back pressure when letting off the accelerator whilst driving for the first 5 or so minutes. The car is currently muching through petrol (approx 14-15L per 100km) and I am sick of the CEL coming on. Honda has told me that the O2 sensor was faulty and giving a false heat reading to the ECU and that I would need a genuine one. I have spent so much money trying to fix this issue and dont really want to spend much more. Does anyone have any reference I could use to wire it up correctly other that what I have provided above?

I also have a VAFC in my vehicle, I am not sure that by being dyno tuned to the old O2 sensor and replacing it with a brand new sensor has caused this issue... The car is obviously running too rich. Is the anything I can try before I have to order the O2 sensor? Any auto-electricians anyone can recommend in Melbourne?

Cheers

hmetro24
14-12-2011, 10:37 PM
Did you reset the ecu after you done that?
is that what wires you have?
black - heating wire
black - heating wire
blue - signal wire
white - ground wire

VTECANDY
15-12-2011, 12:07 AM
What i did, before i started the car, i got a paperclip and put in into the OBD1 slot and it still flashed once (o2 sensor) then I had started the car and the CEL came straight on.. Was I meant to reset the ECU before I started it? So i may of wired it right after all? How do i reset my ECU? will i loose my tune? And the wires on the Bosch O2 sensor are: 2 white (heater supply and heater ground), 1 black (sensor signal wire) and 1 grey (ecu ground reference). What i had to do was wire it up to the corresponding pre-existing wires which were attached to the plug that goes into the harness connector. What I did was, with the ignition switch to ON and the harness connector exposed, wedged a multimeter's positive teststick into the connection and the ground somewhere on the chasis to get a reading. I was able to then wire up each wire to the corresponding terminals. So if are saying all I have to do is reset my ECU before i had started up my car?

hmetro24
15-12-2011, 01:23 PM
Resetting the Ecu will not erase the tune. The Ecu will learn everything from the beginning.
Take the battery terminals, and put them back, to know that ecu has been reset, check the clock inside the car if it's been changed that's mean you successfully reset you ecu.

Rewire the O2 sensor, reset the ecu. start the car and let it idle for some 10 min +-, and take it for a drive.

OEM:
white - heating wire
white - heating wire
gray - signal wire
black - ground wire

Universal
black - heating wire
black - heating wire
blue - signal wire
white - ground wire
These information are not mine, So i am not responsible for any outcome.

VTECANDY
15-12-2011, 08:05 PM
I'll give that a go, when I had rewired it,I just started up the car straight after and the CEL came on. The problem is: the o2 sensor wires are White, White, Grey and Black, the wires it joines onto just before the Harness are Black, Black, Green and White. May I just attached the grey (signal) to the green (which should be signal)?

Cheers for you help mate, really appreciate it

hmetro24
15-12-2011, 08:20 PM
I'll give that a go, when I had rewired it,I just started up the car straight after and the CEL came on. The problem is: the o2 sensor wires are White, White, Grey and Black, the wires it joines onto just before the Harness are Black, Black, Green and White. May I just attached the grey (signal) to the green (which should be signal)?

Cheers for you help mate, really appreciate it
http://www.aa1car.com/library/o2_wire_chart.jpg
This should be useful, so the green is the ground

stndrd
15-12-2011, 08:46 PM
Where abouts in Melbourne are you? If your in the S.E suburbs call Peter at 1st Class Auto Electrics on 0402 249 018