Cary---To see if it's the coil (unlikely) try pulling out the coil wire
where it goes into the top of the distributor cap. Use a nail or
something, if necessary, so you can see the spark jump. If the spark is
steady, the coil is probably OK and the trouble is in the points, the
rotor-to-cap terminal line up, or the wires themselves. (Try exchanging
with a sparkplug wire that sends a constant arc to ground) Or, if the
motor runs without misfiring when driven, there may not be an ignition
problem.
Your Blazer uses a high energy ignition system, and is capable of a
spark that you describe. The TR won't come close to this size, but do
make sure that the two wires on top of the coil aren't reversed. (The
wire out of the harness should go to the coil + side, and the one from
the distributor to the coil - side) The coil should have embossing on
the top with the + and - signs.
Dick
From:
caryhenry@hotmail.com(Cary Henry) Date: Thu, Aug 31, 2006, 5:58pm
(PDT+3)
I got the motor running and started tuning it today. It started out
running very smooth, but was lean so I adjust the needles a couple of
times. I got the mixture right, but the longer the car ran the rougher
the idle got. I have the timing set at 10BTDC static, and the plugs are
burning a nice brown. I decided the problem has to be in the ignition
system so I put my ignition tester on the #1 spark plug wire. I noticed
that the spark wont arc at any distance over about .125". This seems
weak to me since my 1985 blazer will arc at a distance of about .75".
Also, about every fifth time the motor turns it misfires. I checked the
#2 wire and the same thing, missed about every fifth fire. I have a new
cap and rotor, and the gap on the points is within specs. I think the
coil must be going out, but would that cause the random misfire? Any way
to test the coil without purchasing a new one?
Thanks,
Cary
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