Re: that damn 16v conversion

[Brad Sheridan <brads@mindspring.com>]

At 09:00 AM 9/12/99 PDT, you wrote:
>It's the negative (#1) power that gets to the coil that is controlled by the 
>ICU, no? If I were to give this coil a definate ground, would I be forcing 
>this coil to make a spark? Could I wring its little neck?

To create a spark, you have a constant 12V supply on one (+)side, and the
control circuit on the other(-). The control circuit grounds the - side For
a short period of time(a few milliseconds). Because the coil is very low
resistance, this creates a large current flow into the coil, and a magnetic
field builds up in the coil(like a transformer). To fire the coil, the
control unit quickly removes the ground signal from the - side of the coil,
allowing it to float. This causes the magnetic field in the coil to
breakdown, and causes the spark. If you wire the - side directly to ground,
you will be constantly charging the coil but never ungrounding it to fire.
In fairly short order, you will burn the coil up.

  If there is an initial spark, it sounds as though the coil is good, and
the IC igniter probably is as well. Have you checked the distribtor? If the
Hall sender is bad, the IC igniter will never know when to make a spark.
Also check to make sure the distributor is actually spinning when the
engine does(ie. is timing belt OK?) If the distributor isn't spinning,
there are no signals from the Hall sender to the ignitor. And then the
ignitor will not know when to make a spark. The only thing I could see that
could be wrong with the ignitor is if somehow the circuitry that reads the
Hall sender signal got fried. And I don't think this will happen unless
there is a pretty serious miswiring there. One more thing to check,
assuming you are using all of the 16V electronics. The output from the Hall
sender goes to the knock box, which handles the timing curves, knock sensor
retard, etc. It then puts out another signal to the IC ignitor, which
actually fires the coil. So if your knock box is bad/miswired no sparks
will happen.

Brad


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