[urq] Looking for a MAC-02 for 1983 URQ

[Ed Kellock]

Has anyone offered up this link yet?

http://www.isham-research.co.uk/quattro/wiring/Typ85/mac01pin.html

It seemed a fairly thorough run-through of the ECU when I was chasing
demons in mine.

Ed

----- Original Message ----- 
From: "Buchholz, Steven" <Steven.Buchholz at kla-tencor.com>
To: <urq at audifans.com>
Sent: Wednesday, November 02, 2005 7:12 PM
Subject: Re: [urq] Looking for a MAC-02 for 1983 URQ


> ... that is not sounding good ...
>
> ... I looked at the schematic I have and it looks like the switch
inputs
> go directly into a LSI device ... the input port the processor
reads.
> You may be looking at a new ECU after all ...
>
> It wouldn't hurt to hook the wires up and measure the resistance to
> ground at the ECU end just to be sure ...
>
> The thing is your description of how it works makes it look as
though
> the WOT switch is "backwards" ... does the switch on your car have
three
> terminals?  If so, you could move the wiring loom from the "N.O."
> contact to the "N.C." one and see what happens.  One other WAG ...
> measure the resistance from the terminals on the switch to ground
with
> the wiring loom disconnected and the switch in both positions ...
> perhaps there's some sort of internal short circuit in the switch to
the
> body ... extremely long shot I admit, but if it can exonerate the
ECU it
> is worth it!
>
> Steve B
> San Jose, CA (USA)
> >
> > Here's what I measured:
> >
> > Idle switch tripped, wires disconnected: 0 Ohms.
> > Idle switch open (throttle partially open): inf.
> >
> > WOT switch open(throttle at idle), wires disconnected:
> > inf.
> > WOT switch triggered, wires disconnected: 0 Ohms.
> >
> > Thoughts?
> > >
> > > >From this follow on description I'm almost
> > > completely convinced that
> > > what you will find is that the WOT (FT) switch is
> > > operating an a
> > > normally closed position ... it should show infinite
> > > resistance until
> > > the throttle is opened far enough to engage WOT mode
> > > ...
> > >
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