I'm currently helping my friend rewire his 1975 f100 390. I have most of the AAW kit installed. We're at the point where it'll crank with the key. We installed a new duraspark harness, icm, coil, and solenoid but we aren't getting any spark. I followed the diagram to a t and am stumped. I installed the ballast resistor that came with the kit but seem to keep getting a constant 12v at the coil but no pulsing. Any help would be much appreciated.

 

Note: The pink wire is the resistor. With the ceramic ballast resistor and the pink (OEM) wire resistor you've doubled the resistance essentially if you are connecting to the original (OEM) pink wire.

IGNITION COIL TEST
1) With ignition off, check secondary resistance between coil "DEC" (negative) terminal and coil tower. See Figs. 1 and 2. Resistance should be between 7000-13,000 ohms.
2) Check primary resistance between "BAT" (positive) and "DEC" (negative) coil terminals. Resistance should be 1.13-1.23 ohms (.71-.77 ohms Dura-Spark I ignition system). It resistance is not within specifications, replace ignition coil.

 

I did the tests on both coils I have and both checked out within spec.

 

Here is a link for the complete testing of your DuraSpark system. The ceramic ballast resistor is or isn't connected to the OEM pink wire ballast resistor ?

 

It is connected to the 12v ignition wire coming from my new American auto wire harness. In the aaw diagram it also shows it going into the ballast resistor

 

His pink wire is no longer a "resistor" as he's rewired the truck, there wasn't originally a ballast resistor but he's added one to take the place of the original resistor wire. The AAW kit only has provisions for a one wire alternator so that pink wire is just 12 volts all the time with the ignition on.

I see a blue wire coming off of the I side of the starter solenoid, where is that going? It should be the brown wire according to your diagram. Does the truck seem to get any spark at all in the run position? Like when you're cranking it you're not getting spark right? Check for power to your coil both in the run and start position and see what you get.

 

Switch to a pertronix ignition. A single key on hot wire to the coil ids all you need. AAW’s basic harness supports this.

 

Do you recommend that over going to a hei?

 

I sure would. The Pertronix system is super simple and has a good reputation for reliability.

 

I have the AAW harness and went with Pertronix in my truck. I’m sure HEI has is merits but I liked the OEM styling of the Pertronix. The amount of space the HEI distributor requires was also a consideration.

One wire was the ultimate selling point. Can’t beat the simplicity and the reliability. Less parts means less to go wrong. And as I mentioned earlier it still looks like a Ford.

 

I have seen a couple of duraspark modules in my time that have the red and white wire reversed at the plug. You might try reversing that connection. It wont hurt anything to try it. Make sure the yellow tach wire isn't grounded somewhere under the dash. Could have the ignition wire going to the wrong terminal on the ignition switch, check for 12 volts at the coil while the engine is cranking. The one time I was left stranded by a duraspark system, the ground wire going into the distributor broke, so check for continuity between the distributor housing and the black wire at the duraspark module. My dad ran pertronix units on an old Galaxie, they failed twice. I owned a Cadillac years ago that left me walking with a failed HEI module, so me personally, I like the duraspark system. Once you get it figured out, it isn't that much more complicated and seems to be about as reliable as the other options available. Just my two cents.

 

The pink wire is a ballast resistor as long as the wire is of sufficient length and gauge, full stop.. And until I asked "The ceramic ballast resistor is or isn't connected to the OEM pink wire ballast resistor ?" and was answered, You, or I didn't know for sure, did we?

 

The pink wire is just a wire, everything can be called a resistor by your definition. Of course everything has resistance. My point is that the stock wiring harness had an actual "resistor" wire and that is no longer there, and I am familiar enough with the AAW kit to know that that's just a plain wire.

As far as one wire setups, I have a summit ready to run distributor currently and it's been reliable enough. I just don't really buy that any of them are any more reliable than the duraspark, plus with a duraspark you don't have to tear into the distributor to replace a module. (Of course it's easy enough to replace a pertronix or HEI module too). I think the perception that the duraspark is unreliable is because they're usually very OLD.

 

In post 1 the OP stated there was 12 volts at the coil positive, no voltage pulsing.
In post 2 the coil was tested good.

The constant 12 volts at the coil positive shows the is no current flow thur the primary ingition circuit. And we also know that the problem is downstream of the coil negative.
If you ground the coil negative, with the key ON, you should see the 12 volt reading drop in half, or 6-7 volts. If the ballast resistance is the same as the coil primary resistance, they will equal share the supply voltage or to say each will drop 6 volts.
At this point you should also feel the coil and ballast getting warm. I would measure the ballast resistance, should be 1-1.2 Ohms.

The duraspark ingition module needs to be power up and working, as the current flows through it (only when powered on), to a grounding point inside the distributor. The current flow into the DS2 ignition module is ... "IN the green wire and the back OUT the black wire". Keep moving the added ground wire downstream until you find the open circuit. I am not sure if auto parts stores still test DS2 ignition modules, but they used to.

Assumptions I am making.
You have a clean new source of power, and not using the original resistor wire as a power source.

You have a blue grommet DS2 ignition module. I really don't know how a DS1 works internally. A DS2 ignition module conduct current with the key ON. which is where the "warm coil test" came from.

Good luck, Jim

 

You didn't say what the condition of the distributor was. New?? New parts inside?? Old used?? The distributor could be your problem. Pickup coil bad, missing rotor. Time to start testing in a systematic fashion.