Starting to lose faith after O2 sensor change

Hi guys,

So after changing a faulty o2 sensor with a new one my car is running like a bag of nails, miss firing, no power, and when I turn the LPG on you might as well just park it up.

Any help here guys as at the moment its just one thing after the next and the funds aren't unlimited :-(

Should I have changed them both?

I'm going to get engine codes later today but just thought I'd post now incase its a simple fix

Cheers
Phil

Ecu coolant sensors have caused me a lot of problems on various cars-see what scanner says temp is also maf readings.

Lastly if all seems fine air leaks or long term fuel trims.

I haven't seen previous issue discribed-But it may help with further checks

Thanks for the pointers fanatic, I just can't comprehend that the reader showed an o2 failure so I replaced it bearing in mind it was running great and since the change I now have a bag of nails. Could a faulty o2 sensor mask other problems?

Cheers
Phil

have a look at long term fuel trim as a search on here or google.

provided the part is compatible and you have replaced faulty one it would look to be long term fuel trim.

BUT

From experience it is worth checking with scanner live data looks within spec.
I have had air flow meters go out of spec and not bring mil light on on vauxhalls

Ok I have read codes and have 3 which are

P0154 - O2 Sensor Circuit No Activity bank 2 sensor 1
P1319 - Missfire Detected at low fuel
P1667 - Anti theft alarm fault drive cycle A

I also have real time data pic see attached




O2 sensor 2 bank 1 looks suspect, so can anyone confirm which side it is as I've replaced the drivers side one. If it is the driverside does it mean a duff sensor or is it the miss fire that is causing it.

I'm lost so any help would be great

Cheers

Bank 1 is the Bank with Cylinder one in it which is on the passanger side....

Some models have 4 Lambdas - 1 before the cat and one after and for each Branch!

Sensor 2 is usually the downstream sensor (the one after the cat) but I could be wrong!

So I have definitely fitted the new one to the correct side, and I only have pre cat O2's non post cat.

Looks like i'll get another sensor and test

Have you replaced it with the right type Lambda? AFAICR P38 Lambdas are not the standard type (voltage wise.)

is there any easy way to tell?
I purchased the one that was for my year and for the Thor engine but was never offered any alternatives.

Tomorrow afternoons job will be to swap over left to right O2 sensor to ensure fault follows, then I can hopefully identify the fault.

Do you have access to a good Air flow meter, I would just try that first, swopping it with the good one and re test.

I don't rangy35, but I can't understand that all I have done is swap 1 o2 sensor and instantly my troubles started.

I'm going to put the old one back in and see if everything goes ok.

You're getting zero volts off the sensor - either the +ve wire has broken after being disturbed or the Lambda is faulty.

StuckAgainSteve said:

You're getting zero volts off the sensor - either the +ve wire has broken after being disturbed or the Lambda is faulty.

Click to expand...

I'd be tempted to build a little device to send a .455v signal up the Lambda wires, a single AA battery and a zener diode with e 4.8Ohm pull down resister should give you .455 Volts - stick that up the signal wire and see what the OBDII reader says.

Thanks Steve, I checked the sensor reading that you pointed out. I had purchased 2 new sensors so thought I would try the other new one and the same thing 0 volts. So put the old one in that was reading a circuit error originally and volts read the same and surprisingly no codes off the original sensor and car running like a dream.

so both sensors getting returned tomorrow and i'll discuss the issues

I'll update on progress as I still want to change the 2 of them.

My front prop shaft recently came apart at the front UJ and hit the O2 sensor bending it slightly.

The engine seemed to be running just fine, but over the following weeks, having replaced the prop shaft and the transfer box (because it smashed that too!) I noticed the engine note wasn't quite right and I seemed to be slightly down on power on steep hills especially on LPG, but not drastically.

I hooked up an OBD scanner last weekend and found that the O2 sensor was knackered mine is pre-cat too.

I replaced the O2 sensor today and the engine is running just fine.

The OBD scanner says everything is OK.

Even with the 02 sensor at fault, it wasn't running like a bag of spanners, so I would think that your new O2 sensor is faulty or of the wrong type.

Mine is a 2000 model 4.6 with Bosch Motronic.

The part from Island 4x4 was: Oxygen Lambda Sensor P38 00-02 (Britpart) MHK100940 £33.33

You have the same year engine and the 2 sensors I purchased were exactly the same from island. So I need to speak to them tomorrow as the ODB evidence shows no voltage on either but original is fine.

Its a weird one