[urq] Finally re-assembled engine and car...won't start

[Thatcher Hubbard]

That is, in fact, what I did Steve.  The car started on the first try
after getting the distributor coil to fire.  The issue now is that it
will die if I don't use the throttle to keep it a 1000rpm.  Both
Brandon and a local mechanic friend of mine suggest that a vacuum leak
is the likely problem, so that's what I'm trying now.


On Wed, 3 Nov 2004 17:32:41 -0800, Buchholz, Steven
<steven.buchholz at kla-tencor.com> wrote:
> ... still going through e-mails ... but thought I'd respond to this one
> ... apologies if anyone else has already done so in a subsequent post.
> 
> It is quite a simple test to loosen the distributor and rotate it a
> little to test your theory ... I did some reverse engineering of the
> MAC-02 and found that there is a logic AND gate in the circuit that
> provides the reference sensor signal to the processor, this gate allows
> the signal from the reference sensor to pass through only if the Hall
> signal is in the active window.  On newer cars the circuitry is a bit
> more sophisticated, but on the urqs which use the MAC-02, if a problem
> develops with the Hall Sender or the relative timing changes the engine
> will cease to run ...
> 
> Steve B
> San Jose, CA (USA)
> 
> 
> >
> > The TDC sensor is in the top of the bell hosing. It reads a pin on the
> > flywheel. It is a much more accurate way to measure the
> > position of the
> > crank than the hall sensor. However, being a 4 stroke motor,
> > the pin passes
> > the sensor twice for every revolution of the cam. The hall
> > sensor is used to
> > determine the correct pass of the pin to use for ignition
> > timing. I have
> > heard that this comparison only happens during the starting
> > of the motor and
> > once running, only the flywheel pin is used. However, on a 3B 
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