I’m looking for technical help or recommendations on: Finding the upstream O2 sensor…
It has been a mixed day for my MX-5. I completed my first proper repair, replacing the shift boots, and it went pretty well!! Then I took the wheel off to find the O2 sensor, based on a bunch of videos/guides I’ve read, and it’s not there…am I looking in the wrong place?
My understanding is it should be in the downpipe before the cat, and the guides I’ve watched all say it’s easier to go in through the wheel arch. I mean, look at 1:49 of this video:
I then tried to take off the heat shield to see if I could get a better look. The first bolt started moving alright, and then snapped - how screwed am I?
It looks like you have had a frustrating day, but nothing looks too tragic here.
I had a quick look online to see where the O2 sensors was located, and came a little unstuck actually, looks like you were heading the the right direction by starting from the headers.
The snapped bolt is annoying but you will need to get the heatshield off to see how easy it will be to repair. I would suggest getting some WD40 or Plus gas on the other stud / nut and let that soak for a little while before you attempt removing that one.
Just note though, make sure once your done you degrease the area thoroughly again otherwise it will smoke for a while once back up to temperature.
if that is a success, take a another photo of the other damaged bolt and then we can see if their is any meat left to wind the stud out or if it will have to be drilled out.
As for your brakes. Yes you still have a healthy amount of meat on the pad, but check your others too as well as the inside of your discs, as its not unusual to have uneven pad and disc wear if you have sticking calliper slider.
Its hard to give a proper comment on the disc without seeing the insides. Sorry I wouldn’t make that call. But from that image it looks ok.
Some progress on solving the mystery - I’ve got the 1.8 VVT engine, which has a totally different setup. Looks like I do have the stock downpipe (here or here as examples), but frustratingly I can’t see a hole in either of those pictures that looks like the O2 sensor slot. Makes me wonder if it’s further down the pipe. Found another ebay listing that suggests it’s not on the back of that section…
Noted on the WD40 - will give that a go over the weekend hopefully, and get some more pictures if I can.
that sounds like progress then, on that note actually I did come across a video where they had a o2 sensor in the centre section of the exhaust system. Cant find it now to verify what model that was from.
