still more 90tq advice needed

[Huw Powell]

> Thinking about the O2 sensor, I'm wondering if I
> should use the location on the exhaust downpipe
> instead of on the cat where the stock 90q location is.
> Currently only 2/3 of the exhuast is going through cat
> (big leak before). Where do you 90tq guys measure O2,
> at the cat or downpipe ?

Maybe you just pointed out a big issue.  If you have leakage before the
OXS, air could be getting into the stream being measured, correct?  That
would give the OXS some O2 to sniff, and I think that makes it think...
"lean" - and try to make the mixture richer.  Maybe as rich as it can
get it, since it can't get rid of that air leak.

Before trying to tune and get the car running right, the OXS has to be
"sealed up" in a sense as an integral part of the engine system, ie the
only thing it should "see" is exhaust, exactly as the engine is
producing it.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/