Duster turns over but wont start

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7

73 Plymouth Duster

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Hey guys so I have an electrical problem that has resurfaced. the duster will crank all day long but wont start. drove it into garage just fine and now nope it's dead.

I have done a ton of research and had a lot of electrician guys help me with no luck. I have: Replaced the ECU twice to make sure I got a good one
replaced the ballast resistor
replaced the magnetic hookup
and replaced the coil
All the points, cap and rotar look good and clean but I am getting no spark out of my coil. The confusing part is I am getting battery (12ish volts) to the positive side of my coil in the run position (with the wire unhooked from coil) but when I start cranking the voltage drops to a dead zero. To fix this we temporarily jumped 12volts from the battery directly to the coil (unhooking the wireing harness wire of course)
This ensured we WERE getting 12 volts to the NEW coil (and old one since test was performed both times) and no spark out of it. This leaves the negative terminal? I unhooked the tach for now but I am at a loss. we tested 6 ways to saturday too, with old ecu box, old coil, jumping across ballast resistor and any combination of those. nothing does anything to help.

All new components and jumping 12 volts to the coil and it wont even make a hint of starting, even if it did I'm only getting 12 volts on the run, and 0 volts on the start. Im confused. any electrical guys out there?

Thanks
 
The ecu is FOR CERTAIN grounded?

You checked the reluctor gap in the distributor?

Put your meter on low ac volts, hook it to the two distributor pickup terminals and crank the engine. You should get about 1v ac out of the pickup.

How certain are you that the connector for the ECU (example) or the pickup connector (suspect) are both making good connections? Work these connectors in/out several times to scrub them clean and feel for tightness, and visually inspect for corrosion/ damage


Since you have already thrown most of the parts in the system at it, I would do the following:

Either obtain a second (parts of) a junkyard harness with the distributor and ECU connectors, or else see if NAPA has those connectors. Wire up a "jerry rig" circuit on your bench, lay it out, so you can test the components individually. Don't forget to ground the ecu.
 
Chk that plug between the distributor and harness.
More than couple of times I have seen that connector loose contact randomly.
I took that connector out and soldered the wires together because of that happening on my own car.
Crimp the two female connections a little, plug it back in and try it.
 
What about the fusible link..
So when you hook up a straight lead to the coil it fires up?
The alternator did not ground out meaning one of the wires is not touching the engine block (i had that happen to me)Burned up the wire.
 
-Thanks ill try and double check the distributer leads but they are pretty tight
-no i did not run out of gas, you can pull the air cleaner off and the accelerator pump still squirts in gas when you hit the gas pedal, plus i just filled up.
-and no "duster44d" when I hooked a hot wire from the battery directly to the coil it did not start.
my conclusion is that it has to do with the signal between the coil and distributer.
-and ya I am sure everything is grounded. I have been through all of this electrical on other parts of my car and it always seemed to be a ground so I was extra cautious in grounding things.
-I plan to go to msd pretty soon and just re-wire it. I think it may be a bad wire or something but I have no idea, today I plan to look at my wiring diagram today and ohm check all my wires and make sure they aer connected and not in more than one place.
 
get a test light and check for power at the ballast resistor...

probably the connector at the bulkhead is the problem...had same problem with my 73 Duster..

It would just die...i chased it by changing out parts..finally moved bulkhead connector around and the power went on then off...
 
There are two ignition wires one for start and one for run. It sounds like one is shorting out. It happened to my 72 duster I'll post the diagrams for you.
 

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I wasn't getting spark about a year ago and tried 3 different ECU's before I got a good one. They weren't new, they were given to me (I know why now).
 
So I traced my wires yesterday to a loose connection under the dash from the ignition switch, still a little confused about the symptoms I was getting but no nne can really describe how and why electricity does and goes where it does haha. Thanks for all your help.
 
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