still more 90tq advice needed

[ed armstrong]

Thanks  Huw, Mike G., Javad, Jay et al. for your
input.

Looks like I've got some more homework to do. I
haven't paid much attention to measuring signals other
than timing and rpm (and my nose and ear). I actually
have a special adaptor to measure the current in the
CIS differential pressure regulator so I'll check and
see what the computer thinks the mixture should be.
Playin around with the mixture, I been careful to
count the turns rich or lean like some of you
suggested.

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 ?

I'm also using a new coolant temp sensor, so I should
be OK there. I'll check it too though.

I'll probably have another report in a few days.




--- Huw Powell <human747 at attbi.com> wrote:
>
>
> > I thought I was making progress with this beast
> but
> > I've still have mucho problems. There is still
> smoke
> > coming from the car even after an extented warm-up
> and
> > the spark plugs are always black upon inspection.
> >
> > Things improved when I removed the bypass valve
> from
> > the system by clamping the valve inlets and
> outlets
> > shut. There is now a steady idle, but the car
> misses
> > and hestitates on accleration. I actually leaned
> out
> > the CIS mixture one turn and it helped the idle
> > somewhat but still smokes.
>
> One turn is a lot - and since that one turn helped
> "but not enough," why
> not try going further?  Just keep track of how much
> you adjust it, so
> you can return it once you go too far.  When it is
> closer, try 1/3 or
> 1/6 of a turn at a time.
>
> Also, while doin this it is good to be measuring
> *something* to see what
> you are doing.
>
> I think your engine has a frequency valve, right?
> There should be a
> little plug hanging around where you can measure its
> duty cycle, it
> should oscillate around 50% or so when the mixture
> is right, though
> usually people set it a tad rich for more fueling at
> WOT (like 40%).
>
> If you can't find or identify that, at least measure
> the OXS output.
> When idling properly it should oscillate around .5
>
> If it is pegged towards the 0v or 1 end of its
> range, the car is too
> lean or rich for the computer to compensate.
>
> You may also have problems with sensors - such as
> the one that tells the
> computer the engine temperature.
>
> and here's hoping it's still just too rich, and not
> an oil leak problem.
>
> --
> Huw Powell
>
> http://www.humanspeakers.com/
>
> http://www.humanthoughts.org/


=====
-ed

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