O2 sensor thread

[PJR-Elan]

All,

Today I slowly eased out the blanking plug in the exhaust so that I can fit an O2 sensor and go closed loop.

The plug slowly eased out -woohoo I thought- but 8/10th of the way out it then seemed to cross-thread itself. Eventually, with too-ing and fro-ing I got it out, but the thread in the manifold looks pretty bad (but not as bad as the plug). Looks like there was pitting from rust about half the depth in, and everything above that has been damaged.

I’ve bought a M18x1.5 thread chaser, which I hope will restore probably the 2/3rds of the thread depth. If it it worse than that, has anyone managed successfully to install a thread insert? Access looks ok, but it’s quite a big thread to repair.

The pre-cat on mine has nothing in it, so a bit of swarf down there should be ok.

Thanks,

Phil

[alan e]

Do you have a chip to go closed loop and have you checked that the wiring is connected to the ECU ?.

[PJR-Elan]

Thanks, the wiring is there, but I haven’t bought the chip yet. I was just getting the sensor in place whilst the car is off the road with the oil cooler pipe being replaced.

[alan e]

Sometimes the plug is there by the sensor but the wiring loom ends under the inner wing and you will have to run wires from inner wing to the ECU it's worth checking i think you will find the info on the Wiki.

[Rocklobster]

You've probably done the job by now, but if not, full wiring instructions are included with the Mountain chips and if I can follow them, anyone can.

I bought a thread chaser too and although it seemed to clean the threads up, the O2 sensor was a real tight fit. Make sure you buy a decent sensor, not a cheap one as they're crap. I bit the bullet and bought one from SJ Sportscars eventually an it runs great.

A very worthwhile mod.

[NewLogik]

All,

Today I slowly eased out the blanking plug in the exhaust so that I can fit an O2 sensor and go closed loop.

The plug slowly eased out -woohoo I thought- but 8/10th of the way out it then seemed to cross-thread itself. Eventually, with too-ing and fro-ing I got it out, but the thread in the manifold looks pretty bad (but not as bad as the plug). Looks like there was pitting from rust about half the depth in, and everything above that has been damaged.

I’ve bought a M18x1.5 thread chaser, which I hope will restore probably the 2/3rds of the thread depth. If it it worse than that, has anyone managed successfully to install a thread insert? Access looks ok, but it’s quite a big thread to repair.

The pre-cat on mine has nothing in it, so a bit of swarf down there should be ok.

Thanks,

Phil

I've helped a friend with this and at that time we've used a kit like this one featured in this video but usually it should be good with the thread chaser :

Repair of oxygen sensor thread

[Brit-Car-Nut]

I believe the O2 Sensor is the same thread as the old 18mm spark plugs. You might be able to find a cheap thread chaser that will clean up the threads?

eBay UK item Number: 382941052013 would work. £8.05 & free postage...