MOT fail...CO reading
 

Took HiHo for a MOT today after being wrapped up in the garage since Sept. I had changed the plugs ( 06's) a few days before.

Had a catastrophic fail on the CO reading at 11%

Haven't changed anything since last year and it went through at 3% ( or there abouts ) standard non cat figure.

They suggested O2 sensor, so I got home, had a look, and there isn't one?? Is that even possible?

Is there not a 02 sensor on the exhaust headers at the up pipe flange on the early scoobs ?

If it's a real early one it may be in the header. The wire comes up the left side of the cam belt cover with a connector near the corner of the cover.

Cheers Scott, yep 3 wire one in the headers.

Soooo...If this was faulty, wouldn't it throw a cel?

Only if you do a diagnostic test
If it's dead it probably running about 12AFR instead of 14.7.
They run better disconnected as it won't be getting a duff signal.

Just a thought have you dumped and put in new fuel?

I did think of that this morning, and that when changing the plugs I could have unplugged the lamda. I'll give it a good going over Saturday.

Mine ran like crap on year old fuel even with closed loop lambda.

Popped in a new Lamdba today and the idle speed has gone by 150 ish rpm and it get to normal operating temp quicker? Is that normal?

Well, the Lambda dis the trick, reading dropped down to 1.3%.

Result.....