90tq Turbo Conversion Timing Pin Placement

[Pat Korach]

Christopher

Why didn't they drill a small hole for the reverse side
of the pin and with a small punch tap it out?

Pat Korach
Kirkland, WA

Orin Eman wrote:

> > Well, my friend who was doing the timing pin for me ran into trouble and
> > broke off a hardened steel pin in the correct location.  We were unable to
> > remove it so I had him install another pin next to it, about 1.8° advanced
> > of the correct position.
>
> > see http://www.teenaflanner.com/chris/90tq_turbo_conversion_gallery/ for
> > pictures of the goof-up
> >
> > My question is this:  what will this do to the engine operation?  I can't
> > adjust for it by changing the distributor orientation, can I?
> >
> > There is something basic that I don't understand.  What does the computer
> > use this signal from the flywheel pin for?  The distributor takes care of
> > ignition and the injection is continuous, right?
>
> The correct position of the pin is 62 degrees before TDC on cylinder 1.
> Ignition timing relies on this and the flywheel teeth almost exclusively.
> The hall sender signal from the distributor only serves to indicate
> whether cylinder 1 is on the compression or exhaust stroke.
> This pin must pass its sensor during the hall sensor window in
> the distributor or the engine won't start.  Moving the distributor
> can therefore result in a non-start condition.  The ECU also
> relies on the hall sensor to reset its cylinder counter so if the timing
> pin signal is out of the window at higher RPM, the ECU can lose track
> of which cylinder is being fired... resulting in some incorrect tables
> being used in detecting knock.  My guess is that this just causes
> knock to be detected when it shouldn't, hurting performance.
>
> If the pin is advanced, all your timing will be advanced.  The knock
> sensor will save you in general, but you may get forced to the
> regular fuel timing map which will cost in performance.
>
> Orin.