[Diy_efi] O2 says rich, car runs lean..

[Michael Richards]

On Tue, 13 Jun 2006 22:07:04 -0700, Frank McCracken wrote...

> Michael,
> Could you please elaborate on o2 sensor placement? I have my 3 wire
> sensor mounted facing up at about a 45deg angle.
> Frank.

If the sensor is facing up at a 45 degree angle it is bad. This has been
known to kill sensors (years ago I killed a few expensive sensors from
this). On some cars condensation will get in there and settle on the
sensor. Then the sudden heat shock will break the ceramic based element
inside. This is how the bosch rep describes it. I do know that I fixed
the location on my car and it stopped killing sensors. You can probably
get away with it a little lower than midway on the pipe but it's a good
rule of thumb. I suspect too that the bottom of the exhaust may suffer
from a higher HC content as it will be heavier but I've never done any
experiements to validate this. I like the heat pen trick given in
another post. Normally I just rev the engine a little and with an IR
pyrometer look for about 500C. The exhaust temps during cruise usualy
make up for the difference. 

-Michael
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