Re: IML: Ignition failure II

[Kenyon Wills <imperialist1960@xxxxxxxxx>]

cleaning the bulkhead connectors solved half of the
problems.  The worst half, I might add.

Here's what's left:

The car still misses.  It runs great when cold, but
after about 30 minutes of driving, runs poorly at the
top and bottom end of the RPM range, with misses that
feel like the spark isn't getting to the plug.

At idle, the engine jumps and shakes more than normal,
indicating a miss that coincides with the sounds it
makes.

When I am on the freeway and go to WOT, the thing
starts to miss, not unlike the electronic rev-limiter
on my sport bike.  This is at about 80 and under
pressure.

When I coast, the idle drops and then the car misses
and dies at stop signs.  I have to keep a toe on the
gas to prevent this.  Idle speed is not set too low,
and car idles fine when started from cold.  Idle set
screw has little room to go higher but seems fine.

The thing that kills the engine feels like its two
cylinders in a row or something not getting spark and
the thing shudders as it does so.

I had the distributor cap off and the rotor seemed to
have excessive play, not that I know what that would
be.  If you described the circle that the outer edge
of the rotor makes, the rotor pivots back and forth
about 2-3cm Seems sloppy to me.  I have not put a
timing light on it to see if the spark timing is
jumping around.  Plan to do so, right?


Couple of other notes that may or may not affect this:
Car has medium exhaust leak on one bank that is only
audible at idle and low RPM.  Muffler on same side has
split and makes a rushing air sound, so backpressure
is lower on that side, but I don't imagine that
affecting the car this way.

Also, when I got it, the car had a fancy MALLORY
ignition module on it.  I got it tuned, and went back
to the stock setup with a coil.  I can imagine that
this problem was present before and that someone tried
to "solve" it with the MALLORY item.  Did not drive on
that system, so can't comment on whether it fixed the
problem or not - sorta doubt it, but it is evidence of
 prior issues in the ignition system.  

Besides using a timing light and running the car
through its rev range looking for a wobbly rotor, any
other tests to do? 

Kenyon Wills
 
 






















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