motocraft ignition wiring diagram

[Dennis 460 ford]

Hi there,

i've got a little problem with my ignition computer. I am looking for a wiring diagram of a motocraft (model 12A244) ignition computer. Here in the netherlands it's impossible to find anything about this thing! There are 6 wires on the computerurple,green,orange,red,white and black. Can somebody help this dutchman? Also do i have a question about the engine that's in my cobra. The engine is a 460 4v ford engine with edelbrock "high performance" intake manifold. How many HP could it be??

Greetz Dennis
Holland

[Edbo]

It's called a Duraspark here.
Here's a link for you, different part number, but same unit.

http://www.jason.fletcher.net/tech/d.../duraspark.htm

Engine HP would be a wild guess without a lot more info.

HTH, Ed

[Dennis 460 ford]

mmmm,thats weird... I've connected almost all the wires like in the diagram. Only thing thats different at my unit. When i put 12 volts on the red wire en connect the white wire with ground the engine runs. When i disconnect the white wire with cold engine then it doesn't run. When the engine is at temprature it doesn't matter if its connected or not. What the function of the resistor of 1.3 ohms in this diagram?

thanks for your help so far!

[Edbo]

Look carefully at the ignition switch in the diagram...the module red wire is powered during 'run', the white wire is not. The white wire is powered during 'start', the red wire is not.
The white wire is actually an electronic spark retard system. You can ignore the white wire and power the red in 'start' AND 'run' and the engine will run fine. You may have a start problem, though, if you have a lot of timing advance.
Make sense??
The black/green wire on the module is the ground wire. No other wire goes to ground.
The resistor is a ballast resistor for the coil, it supplies full battery voltage to the coil during start and then reduces the voltage during run to protect the coil and module from high current draw.

As for your hot/cold description, that would take some hands-on troubleshooting.

Ed

[Dennis 460 ford]

hi Ed,

it makes sense to me, now! Monday we gonna rewire the engine,so i'll keep in touch with you.

greetz,

Dennis

[Dennis 460 ford]

The ignition system is complete rewired today. But we've still got the same problem. While the engine is running he switches off by hisself,no spark anymore out of the ignition coil. When i check the stator assembly (purple and orange wire):698 ohms with hot engine. With cold engine is this :687 ohms. when i check the ignition coil (from plus 15 to 1 so the red and green wire)with hot or cold engine:3.8 ohms. also do i have 12 volts on the red wire during contact (on the ignition computer and on the ignition coil) and 0 ohms on the black wire (ground). During start do i have 10 volts on the ignition coil an the same voltage on the white wire on the computer. When i feel the temprature of the ignition coil or the computer during running,tis not extreme hot. The computer is replaced on a aluminium plate. When i let cool down the engine it starts normal en there's a spark. Whe've disconnected every safetyswitch.

[Edbo]

Dennis,
From your description I'd say something in the ignition system is getting hot. Not really the engine.
You have three things it can be; the pickup in the distributor, the electronic module, or the coil.
The only effective way to isolate it would be to replace each item, one at a time until the problem does not occur.
You can test the coil after the spark dies by applying 12 volts to the coil + terminal and grounding the - terminal for a second, just tap it on a ground. Whenever you tap the - to ground the coil will make a spark, if the coil is OK.

Make sure you have the ballast resistor wired in the circuit as shown on the diagram. You MAY damage the module if the resistor is not in the circuit during 'run'.

Ed

[Dennis 460 ford]

We've won the battle . Today we've tryed a new ignition module, the engine keeps running now! The enigine is completly rewired and also the resestor is connected now in the cirquit. With the old module we had 12 volts on the green wire during no spark. When we connected the green wire just for a second on ground, then there was 0.3 volts and that means spark and the engine starts. We don't have this problem with the new one. This weekend we gonna rmake our first testrun. The weather is to bad now here ,so we are gonna wait for the weekend.

[Edbo]

Great news, Dennis!

Now one more thing: With a Duraspark system don't ever leave the ignition switch 'on' without starting the engine for more than a few seconds. The Duraspark powers up the coil while waiting to start. If you need to turn the ignition switch on without starting the engine disconnect the - wire at the coil first.

Ed