79 ignition Q's
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Joined: Mar 2003
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From: Boise, ID
79 ignition Q's
I recently took my 302 out of my 86 bronco and put a 79 351M in. but i'm having problems blowing out my ignition module. i've connected straight to a 12V power source and will briefly run but once stopped will not start again. I heard that the original wiring harness has a resistor in the line but i don't know how big it is or how much power is suppose to run to the ignition module. do i have to get one out of a junk yard ( if so were is it at) or can i get one from a parts store? I'm also not sure between the red and white wire when each is suppose to be activated with power and when it's not. Any help
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From: Virginia
79 ignition Q's
If you look at the above diagram you will notice the resistor only goes to the coil supply. My manual says it's value can be 1.05 to 1.15 ohms. So I don't see why you couldn't retro-fit one of those big white ceramic resistors the stores sell if it was the right value.
The red wire gets straight 12 volts in the run position.
The white wire gets 12 volts in the starting mode only. It is used to retard the timing about 12 degrees to make the engine turn over easier. It's a nice feature, but can be left out. If you don't want to have to search out the correct place to put the white wire under the dash, you can buy yourself a starter relay that has two little terminals instead of just one. One of the little terminals will engage the starter as it does now, and the extra small terminal will give you 12 volts when in starting mode only. You can hook the white wire, and the coil to this terminal which will give you the retard during start, and the hotter spark during start. The hotter spark during start is what the resistor bypass is for.
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From: Boise, ID
79 ignition Q's
Thank you very much for the info. I'll give it a try and let you know how it goes. i't just that little bit of valuable info that is left out in most reading, Like chilton thanks again.
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79 ignition Q's
RU, double check the ground wire (black), shown in Franklin's diagram. An intermittant ground will cause all sorts of crazy starting problems with the DS II.
Try measuring the voltage at the coil positive terminal. It should have about 12v when the starter is turning, and about 7-8v with the key on. If you get values close to this, then the resistor wire is OK.
Try measuring the voltage at the coil positive terminal. It should have about 12v when the starter is turning, and about 7-8v with the key on. If you get values close to this, then the resistor wire is OK.
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From: Boise, ID
79 ignition Q's
The black wire runs inside the distributor.is it suppose to ground out through the case?
What does it mean when the coil makes a high pitch squeal?
The wierd part is when i was trying to test it before i did not even have the red wire connected and it ran.
What does it mean when the coil makes a high pitch squeal?
The wierd part is when i was trying to test it before i did not even have the red wire connected and it ran.
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79 ignition Q's
RU, does the 86 have the EEC IV ignition? If so, you don't have a resistor wire. If you're wiring in the DS II system with the 351M engine, do this:
1. Connect the red DS module wire to a switched 12v source; the
white one can be left disconnected, or wire it as Franklin
describes.
2. Trace the coil positive wire (on the 86) back to the firewall, and
wire in an aftermarket resistor, in series, then run the wire to
the DS coil.
3. The larger DS module plug (4 wires) goes toward the distributor.
One of the 4 wires (green) goes to the coil negative terminal.
1. Connect the red DS module wire to a switched 12v source; the
white one can be left disconnected, or wire it as Franklin
describes.
2. Trace the coil positive wire (on the 86) back to the firewall, and
wire in an aftermarket resistor, in series, then run the wire to
the DS coil.
3. The larger DS module plug (4 wires) goes toward the distributor.
One of the 4 wires (green) goes to the coil negative terminal.
