Hi guys,

I've had an engine warning light for a while now and it's due to low voltage on the upstream o2 sensor, I can clearly see damaged wiring under the bonnet near the plug end. 

I've bought a replacement (official Ford), but I can't get the old bugger to budge! I've tried soaking it with WD40 every few hours for a couple of days. I'm only working on a driveway with the car on 2 axle stands, so not much leeway to get a good purchase with a spanner. Also I don't have access to a torch to heat it up. 

I just phoned my garage and he told me he doesn't install other people's parts (I was about to ask him if I could purchase a part through him and sell the other on eBay, but he just hung up so f*ck him, not going back there).

Would I be utterly mental to just cut the plug off and splice the new undamaged plug end onto the old sensor? Not ideal, but I'm running out of ideas. Not only will it need to be done before the next MOT but I can see my fuel gauge dropping by the minute!

 

You need the special socket to be able to get the O2 sensors out. See Amazon:

https://www.amazon.co.uk/Socket-Oxygen-Sensor-Sockets-22mm/dp/B008C7PP6M/ref=asc_df_B008C7PP6M/?tag=googshopuk-21&linkCode=df0&hvadid=309815944779&hvpos=&hvnetw=g&hvrand=7342562657129335621&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006688&hvtargid=pla-348413779320&psc=1

Thanks Unofix, I've ordered it for tomorrow!

Although I've got a feeling it's rusted it. 

To make life a little easier for yourself, first cut the wire off the old sensor. It will just make it simpler to get the socket on. Take the car out for a drive first and get the exhaust hot before you try and get the old sensor out.

This might sound very odd but trust me it's works many times. Try and 'tighten' the sensor as hard as you can before you try and loosening it. The tightening action often stretches the the screw threads by just a thousandth of a inch, just enough for the bond between the threads to break free.

Remember when you fit the new sensor to put a 'tiny' bit of cooper slip grease on the thread before fitting it. 

I totally agree with everything that Unofix have said it all makes a lot of sense, good luck

If you can see damaged wiring it seems a bit extravagant to buy a new sensor. Repairing the wiring would have been my first course of action. 

It is very difficult to properly repair or modify an o2 sensor's wiring. It will not work properly as the sensor vents through the insulation and wiring and solder would interfere with this 

Thanks for all your help guys, I managed to fix it today.

Bought the tool that Unofix suggested, and a breaker bar. As it turned out, there was no room to use the breaker bar anyway, so I just used a hammer to give my little ratchet a few whacks, and that eventually did the trick (I'd pre soaked it with WD40 a few times). Really pleased, as I absolutely did not expect it to budge for some reason. It's a 21 year old car!

Luckily I didn't have to cut the wires because there is a plug about 8 inches along the wire, so I I just unplugged it and plugged the one one in. 

The wires were pretty badly chewed up isetta, not sure what happened, suspect I drove over a branch or something. Who knows. And by the time I bought a new sensor....it seemed silly to mutilate them both and then still leave the old one in! Would have been livid if the actual sensor itself went a couple of months down the line. 

Joe

 

Hi, glad to hear you fixed it. But to be honest I wouldn’t recommend hitting a ratchet with a hammer. If that’s all you had to hand I appreciate you wanted to get it done but they are not really made with whacking them with a hammer as the design use.