I've got a 2.3L in my 99 Ranger with a distributor using duraspark. Thursday an hour and a 1/2 from home and 10 miles off the beaten path the duraspark original motocraft box died(Been working fine for 3 months now). I got a ride to Advance bought a new made in china box I also got a new coil just in case (Newer style 86 Ranger coil) put them on the truck and it ran 1.5 miles and the box died again. Trailered her home and thought it might be because I'm using the original 3.0L V6 coil pack power wire (12Volt)to power the system so I bought a 4 pin Gm HEI ignition module put it in I drove it about 45 miles today and it died when i got home. Every time it fries is at an idle. First 2 times I was idling down a 2 track, 3rd time I was idling at the mail box. Anyone have any idea why it has started fring boxes? I am feeding a tack signal into the 3.0L tack off the negative side of the coil, so that and the power feed are the only 2 wires from the 99 everything else is duraspark, or GM HEI)
HELP Please RB







Orange wire from distributor is on w
Purple wire from distributor is on G
Green wire on C goes to the negative side of coil
3.0L coil pack power wire to B and also to power side of coil
Black wire grounded to mounting screw underneath

 

I don't know why you are having problems with the HEI, but you need a resistor with the duraspark system inline with the coil + wire. The HEI doesn't require the resistor though. Did the HEI module come with the white heatsink grease and did you use it between it and the heatsink? It's special heat transfer grease made out of zinc.

 

It came with it and I used it.

Actually it wasnt white it was clear like dielectric grease, i just assumed it was heat sink. Could this be the problem?

 

The package says it contains Dimethylpolysiloxane but it doesnt say what it is. Could it be dialectic grease for the terminals not heat sink?

 

I see a lot of random parts thrown at this problem, but not much actual diagnosis. How do you know the box is "frying," and what specifically does that mean? Have you actually checked for spark during the failure condition?

 

It could be. Radio Shack sells the heat sink grease in a little tube.

 

When it broke down the first time all I had was a screwdriver a pair of pliers, a knife and a piece of wire. I put the screwdiver in the end of the coil wire and placed it near a ground. I then grounded the negative side of the coil and released and there was no spark. I assumed at that point it was the coil but I didnt want to take a chance at being wrong so I changed the box and coil. Now that I have it home I checked to make sure I have a clean 12 volts and that I have it with the ground I use for the coil and box. I'm not sure of anything at this point other than it has quite 3 times and putting a new ignition box on it will make it run for a short time.

 

Remember, you do not want 12volts on the coil + with the duraspark II box. It should be around 9v.

 

I have the newer box style coil (86 Ranger) that runs off 12 volts, I used one so I could just use the stock ignition wire. What I didnt know at the time was that the box was 9 volts. Funny thing is it run fine for 3 months driven every day without a hitch. When it fried the second one, thats when i found out they were 9V and thats why i went the GM HEI route. But that dont answer why it died with the GM ignition.

 

I can't explain your HEI problem. But with the duraspark II system;

You need to run the stock duraspark II coil. Some people run other coils, but they put a greater load on the duraspark II box and

The 9v thing. The box does get a full 12v to power itself. It's the coil that gets the resistor and has around 9v on it when it's running. The factory had a bypass system that put a full 12v on the coil during cranking only, and then the power for the coil runs through the resistor. So you have two power wires, one powering the coil and one powering the box itself. And then you also have another power wire from the start circuit that tells the box to retard the timing for easier cranking.

 

Was the negative terminal of the coil still hooked up to the rest of the system when you did this? If that's the case, this test won't work anyway. With the key in RUN, the Duraspark module holds the negative terminal of the coil at ground. Grounding and un-grounding the coil externally in this instance has no effect.

I'm not really sure what you mean. There is no ground associated with the coil; the module is responsible for grounding and ungrounding it to produce the spark (I'm sure you're aware). The module grounds through the BLACK wire that runs back to the distributor. This is the sole ground point of the entire ignition system.

That doesn't necessarily point to the ignition module. It could simply be the act of letting the truck sit for a while and jostling things under the hood that coincidentally masks the problem. Make sure you're checking for spark correctly as per the clarification above (if you're not already). If you truly do not have spark during the failure condition, check the resistance of the pickup module in the distributor by disconnecting the distributor, and measuring the resistance between the ORANGE and PURPLE wires coming from the distributor. The resistance should be between 400 and 700 ohms, and neither wire should have continuity against ground. Think about it, why would three modules fail one after another? They are probably NOT failing. The only other explanation (albeit remote) is that your regulator is letting the system voltage sit too high, which fries modules back to back. That's highly unlikely. Slightly more likely is your incorrect coil stressing the module. ONLY run the stock Duraspark II coil with a Duraspark II module. Nonetheless, you absolutely need to test the pickup module.

The ignition module does not use 9 volts; it uses a full 12 volts. The coil, however, is powered downstream of a ballast resistor with the key in RUN, bringing the voltage down between 7 and 9 volts. In START, the coil is powered directly from full battery voltage.

 

The reason I didnt use the stock coil was because I didnt want to wire in a ballast resister, and the 2 different power supplies, I thought changing the coil would be simpler and faster. Hind sight might be different now tho.

One problem i have had with the truck is hard starting if the truck had been running 10 mins or less prior to starting. Which now makes sense.

 

I saw that in my chiltons manual wiring diagrams but my 99 Ranger has none of that going on and wasnt sure i could wire it that way so thats why i changed coils. But if thats what I need to do, I'll go down that road.

 

I am assuming you have a older engine in a newer truck? If you are using the older system, you need to wire it like it was a older truck. I think if you copy the older system ignition wiring, you will be ok.

Also, if you are going back to the duraspark module, get the blue plastic model, and your best bet is to get a motorcraft one from the junkyard. They are known to be better boxes than the aftermarket ones. You can get one from any car or truck Ford, Mercury, any engine, just so the plastic piece around the wires is blue. You might as well grab the coil and it's horseshoe connector also. The duraspark II coil has pins instead of threaded studs for the connections. If the horseshoe connector is no good, they sell new ones in the store.

 

99 truck, mixture of years on the 2.3L. I'm going to stick with the HEI, as that is what I have in my 75 Bronco so i only need to carry one spare in the tool box.
There is nothing in the salvage yards up here in the salt belt that old. I got the one that went bad from a friend who has a ton of ford parts. I also probably have 5 of the old style coils laying around. I'm thinking the pickup is the problem as I'm no where near 700-900 ohms of resistance, so i ordered a reman distributor today so I'm going to give it another try tomorrow.