Thanks for trying to post the pic, but I can't open pics on this website for some reason-never have been able to. Only if they are linked from Photobucket or another site.

What I am unclear on is where this orange wire runs. The engine harness plugs into a four-way plug that hangs off the a/c hose to the right of the brake booster. The wires then disappear into the harness and appear to run to the right side of the engine compartment along the firewall, but the next place I can locate the orange wire is the four-way connector that plugs into the module. From what I can tell, the fault lies somewhere in THAT section of wiring, but I don't know where to start taking wiring apart to locate the orange wire. I'm starting to contemplate simply making four jumper wires and bridging the gap from the plug next to the a/c hose to the module.

Today I ohmed out the pick-up coil, coil wire, and every wire on the engine harness. Everything there checks. Swapped out the coil and the module again. Ohmed the cap and the rotor. I have power to the coil when the key is on. I DO NOT get a blinking light under cranking, so I have a fault somewhere between the engine harness and the module as best as I can tell.

 

Good info here:
1975-79 DISTRIBUTORS & IGNITION

 

Ok, let's review a bit:

No blinking light upon testing means the coil is not getting switched, either because the module isn't getting power, it's not getting a trigger, or it's bad. Since you ohmed out the distributor, et al, that shows good, the problems lies with power supplied to the coil.

Disconnect the 2-terminal connector at the ICM. The RED with BLUE stripe wire coming from the TRUCK (would go to the WHITE wire of the module) should be hot with the key in START. The other wire (WHITE) coming from the TRUCK (would go to the RED wire of the module) should be hot with the key in RUN.

If you have 12 volts in both cases, then disconnect the 4-terminal connector. There should be 400 to 700 ohms between the ORANGE and PURPLE wires coming from the TRUCK. The BLACK wire coming from the TRUCK should have continuity with ground - little or no resistance. The orange and purple wires do their thing inside the ICM.

Thanks to FMC400 for some clarification on this.

If you've done all these tests, again, please forgive me - I've only got a few brain cells left......

Edit: There's also an orange wire going to the heater blower motor from the harness - don't know if this would be of any help.

 

Yo, Moderators or someone with computer savvy!

Please delete my post - #14 - it's messing up and I don't know how to fix it!

Thanks.

Edit: Managed to 86 the non working part....good to go.

 

I was having a no spark problem also, I was stumped because when I pulled a spark plug out to check for spark my engine fired right up. So I started chasing wires, I found two bare wires (they we're also touching) resting on my intake, These wires came from the firewall and we're bad right as the entered the connector at the distributor. I'm going to see if I can find some new connectors and rewire it from the firewall to the distributor. Hopefully that fixes it.

 

Yes , the orange wire goes from the module to the dist. Unplug both ends and check for continuity between pins 3 and 9 on diagram.

 

Back to the drawing board....

Over the weekend I built a harness to directly connect the short harness on the engine to the module to eliminate the possibility of a fault somewhere in that wiring. Checked each wire for continuity from the connector at the module to their opposite ends-all checks positive. Still no spark...I even went ahead and installed a new cap and rotor because I had them laying around.

To review: Power to the coil, power to the module in run and crank. 619 ohms across orange and purple wires. No continuity between either of these two and the black wire. Black wire does show to be grounded. I've tried two modules, two coils, two sets of cap and rotors. New pickup coil installed. Coil wire ohms good.

 

You've changed just about every part in the system. The only thing left that I can think of is the reluctor/armature in the dist. In the 40 years that these systems have been around,I don't recall ever seeing one go bad, but I guess anything is possible.

 

'had the same issue a couple of months ago and chased my tail a couple of times.... turned out to be a bad coil. I replaced it with a coil (Chinese) from Autozone and it was still wouldn't spark. ... then I bought a Taylor coil from Summit Racing and it fired right up.

Allegedly new parts can be bad right outta the box!

Lesson learned: No electrical/electronic parts from China ever again. Dirty commie low lifes producing crap parts...

.

 

Still have a "No blink" scenario, yes?

Let's try something different - If you've done this one before, please excuse.

Check the voltage at the "I" terminal on the solenoid while cranking the engine....this is the coil's ballast resistor bypass when in "START." Its sole function in life is to supply battery voltage to the coil on start. It has no other function, no voltage, no anything while in "RUN."

If you have no voltage check the wiring from the "I" terminal, ballast resistor wire splice and back to the ignition switch.

This probably means unraveling/chasing wires again...sorry.

 

Something just occurred to me a few minutes ago. If this were a points type system I know what each parts function is, but I think I've been over-complicating things because of the 'magic box' on the fender...Tell me if I'm right about this:

The blink test above...with the test light on the negative side of the coil I would have no power until the points closed, right? When the points closed the test light would blink on. So, I should not have power there except when the module tells the coil to make a spark, right? I have a steady light there ALL the time. I had been thinking I should see the test light blink off. I had that totally backwards didn't I?

 

A steady light while cranking means you're getting voltage to the coil but it's not getting a "trigger signal" to interrupt (test light blinks) the voltage signal by the ICM causing the coil to fire.

In a points system, the opening of the points interrupts the voltage signal sending it to the coil (a blinking test light). In other words, there would be voltage at the points all the time until they opened.

Remember when we were in knee pants and use to leave the key on in the family vehicle to listen to the AM radio? Remember how the points would weld together causing a no-start situation? Getting hollered at for this is a polite way to put it...hehehe.

Edit: Since you're getting power to the ICM (red/blue wire to white on the ICM, hot in start) and power out (white wire to red on the ICM, hot in run) and the pick up coil - stator - (purple and orange wires) ohms out to specs, maybe some wiring/connections to the ICM needs looking ator the ICM is faulty. Sorry to keep harping on the ICM but your tests indicate a problem there.

 

I'm hangin' with you on this, my friend....How about we (you) test for primary circuit continuity - the green wire from the ICM.

Can you stick a straight pin through the insulation on the ICM green wire...being careful not to short it out to ground. Stick the negative lead on your DVOM to the distributor base (good ground). Turn the ignition switch to "RUN" and check the VDC at the green wire pin. If you have 1.5 VDC or less check the wiring harness and connectors between the ICM and coil. More than 1.5 VDC, we'll go on to check the ground circuit continuity. Turn the ignition switch off after measuring.

Ground circuit continuity: Another pin deal here - stick it in the ICM black wire, again being careful not to short it to ground. Negative probe to ground or distributor base, ignition switch to "RUN" again and measure the VDC at the black wire pin. If you have more than 0.5 VDC we'll (you) check the distributor ground circuit continuity. If you read 0.5VDC or less the ICM gave up the ghost.

I think you already tested the distributor ground circuit for continuity and it showed good, yes?

Another thought - i have a known good DSII distributor - I checked the distance between the reluctor and magnetic pickup - stator. I have 0.018" distance, snug..with some drag. Just a thought.

Please excuse the long post and more tests....sometimes my one good brain cell kicks in and I move on it....hehehe.

 

Dittos on the .018.Went out to the distributor museum and checked 2 of them. Both the same. Checked one other thing; if you connect an ohm meter to the orange and purple terminals at the connector ,and turn the dist. shaft, the meter will fluctuate. This should indicate a trigger signal at the dist.

 

THE BEAST LIVES!

First off, I want to thank EVERYBODY who had suggestions and diagnostics to try. That is one of the greatest things about this forum; everybody here will help anybody that needs it.

I had kept going through all the diagnostics in the manual and trying what I was told here without success, so I finally gave in over the weekend and called a friend of mine that is an independent mechanic, but used to work at the Ford dealer in town. He came out today to take a look. I don't feel so stupid now...we (he) found the problem, but it took nearly four hours. I NOW HAVE SPARK!

I had carefully ohmed all the wiring from the module to the distributor and coil over and over. I had found a fault a couple of times so I made a jumper to go directly from the module to the short harness on the intake manifold. EVERY TIME I checked continuity from end to end after I put the 'jumper' harness on, I had continuity. But, when my friend and I checked it, we didn't have continuity on the yellow wire. When I was checking wiring by myself I had to unplug everything at each end and pull the distributor/coil end toward the left fender to be able to reach everything. When we were checking today, I held one probe of the volt meter and he was holding the other with the wiring pretty much where it belongs. Apparently there was a break in the original wiring in the short harness on the engine that would connect when I pulled it around testing by myself.

We made an entire new harness to run from the distributor to the module and that fixed the problem. Filthy Beast, you were on the right track, my testing methodology was faulty. I can't believe how many times I checked that wire and it showed good. My friend showed me, when he bent the wire as I had when I was testing it, it DID connect. When you straightened it out, no current.

Once again, thanks for all the help, guys!