No Power: New Battery and Ignition Coil

Hello all,

Background:
New battery. I ran some power checks (with a light tester) to see
where I was getting power. Power going to ignition coil seemed
intermittent...it didn't have power one day and had power the next. I
took off old ignition coil, tested resistance and had an open circuit
betweet terminals. Bought a new coil and installed. Car did fire
twice but never started. Ran some spark checks on plugs and ignition
wire (center wire on distributer) and no sparks. Checked power to
coil...nothing. Now when I put the key in the ignition and turn to run
there is no power at all. No lights, radio, etc. Battery is fully
charged still (put it on a charger). Ballast resister is good (had a
new one I tested). I did attempt to crank it by jumping the
switch/relay on the firewall using a screwdriver to bridge. It
cranked, but no sparks.

Just from chatting with others, they have suggested checking the fuses.
They all looked fine, but I'll check the ends to make sure they are
still intact and don't spin. Could just be hard to see the break if
it's come away from one of the fuse ends.

Possibly the voltage regulator? Wanted to get some opinions before
starting tracing the wires from the battery onward.

 

What make, model, and year of car???

 

1966 Plymouth Barracuda...sorry for leaving that MAJOR part out ;O)

 

Well you could try jumping from battery to the + side of the coil and see if
you get spark.. that would eliminate the distributor parts and the rest of
the primary ignition wiring.

 

Well,

Last night I had a little time to do some checking. Car was still dead
when I started (i.e. no power to anything). Started checking firewall
connections. A lot (most) of the clips/connections are corroded. I'll
get a new wiring set eventually. After pushing and pulling on various
wires (I think the fusible link attachment point is the culprit), I
checked power again and surprise, it was there. Power going to the
coil. Checked for a spark coming from the coil ignition wire and
nothing. Maybe I should change the plug wires while I'm at it. I
don't think plug wires are the problem, as I tested the main ignition
wire (connecting dist. to coil) by putting one end to the + side of
battery and checking the other side with a light tester. 12v was at
least going through the wire. I don't know how helpful or even if that
tells me the wire is good, but it seemed to have continuity. Wiring to
coil seems ok: one wire to( + ) side going to ballast resitor, two
wires to ( - ) one going to dist. and one to tach (a small cylindrical
piece behind the coil).

 

If you have 12V showing up at the *+* connector on the coil, that is a
good sign. The points in the distributor is what switches the coil on
and off to provide the pulsated DC that is needed to invert the voltage
to provide spark. I would suggest checking the points and condensor in
the distributor next. Check the points for pitting and wear, and set
the gap. The lobes on the distributor shaft should be lightly
lubricated for smooth operation. Usually, a new point set will include
a capsule of this lubricant.

With my 1964 Plymouth 273, a good sized spark would jump from the coil
tower with the wire disconnected, and the starter cranking the engine.

Is the distibutor still the 1966 one, or has it been swapped out and
electronic ignition installed? Chrysler offered electronic ignition
retrofit kits as early as the mid-1970's for earlier cars.

If you have electronic ignition, then the diagnostic procedure will
differ.

-Kirk Matheson

 

The firewall bulkhead connector is the source of many problems in the older
Mopars.

When troubleshooting the ignition system you have to understand how the
ignition switch works. When the key is turned to Run, one side of the
ballast resistor is powered (usually with a blue wire) but when the switch
is turned to Start the blue wire shuts off and the wire on the opposite side
of the ballast (usually brown) is powered to bypass the resistor for a
hotter spark when cranking. Just because there is power to the coil in the
Run position doesn't mean there is power in Start; you need to check for
voltage in both key positions. If there is no power in the Start position
check the bulkhead connector first and then the switch.

You might also consider disconnecting the tach sender temporarily to make
sure a fault in it isn't shorting out the whole ignition system.