Need help a possible plugged kitty

[Jim Green]

--- Jim Green <jeg1976 at yahoo.com> wrote:
>
> --- David Conner <conner at cfm.Ohio-State.edu> wrote:
> > Jim,
> > I'm not sure where your O2 bungs are, but it may
> be
> > easier to tap into the
> > sniffer tube.  In my cars the sniffer tube is near
> > the top of the engine
> > above the turbo whereas the 02 bung is under the
> > car.
>
> Yea, um I don't have one of those.  It wasn't a
> priority when doing the header:)
>
> > Scott M has info on testing backpressure on his
> > website.  IIRC he says an
> > old cat read 6 psi back pressure and a test pipe
> > read 3 psi
> >
> > The two cars I tested, both with old cats, were in
> > the 5-6 psi range.
>
> Thanks, those are good values to go by.  I would
> hope
> my 3" exhaust gives only 2-3 psi of back pressure.
> I'll post what I find tonight.

The good and bad news is it looks like my cat is
toast.  If I keep it under 6 psi of boost the car runs
normal at 0-3 psi of back pressure after the turbo.  I
hammered it in second gear, and saw 15 psi of back
pressure!  No wonder why my car seems to be running
hot.  It was almost in sync with the boost readings.
I can get some boost, but it diminishes the hotter the
cat gets I guess.

I guess I'll be investing in a WBO2 meter real soon,
along with a new converter.

Later,

=====
Jim Green
'89 90tq 034EFI Stage II
http://www.geocities.com/jeg1976/car_home.html

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