[v1p3r]

Originally Posted by Shan2nu

. Is the busted sensor causing the engine to run richer than normal? I've been told to expect a slight drop if FE and driveability.

Happened with me, so quite likely.

[Ford Rocam]

Originally Posted by Shan2nu

Somehow, at full throttle, the engine is performing extremely well. Is the busted sensor causing the engine to run richer than normal? I've been told to expect a slight drop if FE and driveability.

Shan2nu

The stock ecu are programmed to ignore O2 sensor at wide open throttle.

The 4 wire O2 sensor are basically heated oxygen sensor, 2 wires for heater feed & ground and other 2 wires are sensor o/p & ground, you can check status of your O2 by connecting voltmeter at sensor o/p , when your car starts from cold the ecu runs in open loop mode, the oxygen sensor operating temp is around 600 deg F that why its heated to bring it in operating range cause the engine is cold, it will measure around .45V on O2 wire o/p but can vary slightly, after some time when engine is warm & Sensor is heated the o/p voltage of sensor starts varying between 0-1v if you see this varying voltage happening quickly then everything is ok & if variation takes a lot of time to vary your sensor is not responding well. Once engine warms up completely it goes in closed loop mode where it takes feedback from O2 sensor.

[Pankaj401]

Once engine warms up completely it goes in closed loop mode where it takes feedback from O2 sensor.

Not if you are running WOT or bad O2 sensor.

[Ford Rocam]

Originally Posted by Pankaj401

Not if you are running WOT or bad O2 sensor.

my dear friend I think you missed what i typed on post # 17 please read that.. its already mentioned.

ford rocam;
The stock ecu are programmed to ignore O2 sensor at wide open throttle.

depending on bad condition of O2 it will still go in closed loop cause ECU also relies on feedback from coolant temp sensor to check for engine warm up before going to closed loop operation. once in closed loop when feedbak from o2 is not correct it will throw an error code.

[dhiman]

Last week i had left my car (OHC 1.5 EXi) with a local garage for a suspension overhaul and after 4 days i get my car back as promised. The next morning, I start the engine and am shocked the next minute to find out that the Check Engine Light (CEL) just would not go. I switch the car off after 2-3 minutes, restart it and the CEL is gone! I was only momentarily relieved to find out later that after a cold start the CEL would not go but would dissappear upon restarting the car. I have read countless threads in here discussing O2 Sensor problems being all too common with OHCs, and hence I had some kind of an idea that this might be the problem aswell. However, I decided to try Dominic's article and try to check the Fault code by myself.

I locate the Service connector, short the connector with a piece of wire and turn on the ignition and voila i get 4 long CEL blinks followed by a short one - hence my code is 41. I look up for fault code 41 and this is what i find - "Primary Oxygen Sensor - Heater circuit malfunction". Hence it is confirmed that my O2 Sensor is not working properly. I am kind of wondering if the suspension overhaul has anything to do with it - because it seems unrelated.

I have no intention of getting robbed at the Honda A.S.S hence I would need suggestion on Brand/Price and specs of the O2 sensor to hunt for. OHC owners having gone through this please guide.

Thanks

[anandpadhye]

Originally Posted by dhiman

I locate the Service connector, short the connector with a piece of wire and turn on the ignition and voila i get 4 long CEL blinks followed by a short one - hence my code is 41. I look up for fault code 41 and this is what i find - "Primary Oxygen Sensor - Heater circuit malfunction". Hence it is confirmed that my O2 Sensor is not working properly. I am kind of wondering if the suspension overhaul has anything to do with it - because it seems unrelated

This is getting extremely interesting.

How to access the ECU service connectors?
What's the location?
Any photos will be a great help.

[dhiman]

anandpadhye

The service connector can be found inside the footwell for the front passenger - around the area where the right knee of the front passenger would rest. You should see two blue colored connectors housed inside a green cover. One out of the two having just 2 pins is the service connector.

I am sorry i did not take any pics - but i think it is fairly easy to trace the connector. In case you need some more info in locating it let me know

[nitroxx]

Well mine is now throwing a Single long one and 7 short which is the VSS i believe? But the speedo works fine and VTEC engages even after the CEL is on. WEIRD? I know.
Trying to solve the issue. No performance loss either.

[autopsyche]

I just changed the O2 sensor on fellow tbhp member DrElivel's OHC 1.5, total damages Rs.4,500 including labor and original Honda O2. His car recently got new piston rings and gasket although the O2 had conked off earlier than that but the car was drivable.

[anandpadhye]

Thanks for the info.

So now, we know how to decode the errors for Honda ourselves and the fellow BHPeans in Delhi have access to reasonable and reliable Honda spares.

@Autopsyche,

Can you guide us on where to go for these things in Pune?
My NHC's front suspension will need overhaul and Deccan Honda says Honda does not support replacing only the polyeurathane/rubber parts...entire suspension (lower arm I think) will have to replaced!
I was also told that the steering column in NHC generally needs overhaul around 70,000KM (I have done 60,000 KM) and again Honda only supports replacing the whole column.
Honda sucks BIG TIME....I should have bought good old Fiat Adventure...it rides our roads easily without such replacements, I am told!

Sorry for a little OT...should I open a new thread fore this???

[dhiman]

Originally Posted by autopsyche

I just changed the O2 sensor on fellow tbhp member DrElivel's OHC 1.5, total damages Rs.4,500 including labor and original Honda O2. His car recently got new piston rings and gasket although the O2 had conked off earlier than that but the car was drivable.

Is Honda OEM Denso? What all other brands do we have in the open market and at what price range please. My mechanic suggested one for approx 2.5K (not sure which brand) - but i am a little sceptical about the reliability.

[di1in]

I used to have a cel problem but when i took it to the mech he solved it. But now the cel stays on at key on, engine off. Upon ignition it turns off. Isn't is supposed to light up for 2 secs as the injectors prime and then go of ? Help please ..

[Manas]

Is there a pattern in the failing O2 sensors?
Which of the two O2 sensors fail more often?
// In BSIII cars, there are two O2 sensors : one pre & another post the catcon... //

But the thing that struck me was that although it seems justified that an Oil pressure problem might not be assigned a DTC, a failing O2 sensor should have been diagnosed by the OBD tool that was used on the car (in the opening post)...
was wondering why the Diagnostic tool not report a bad O2... It is not possible for the ECU to NOT register a faulty O2.