What part number on this coil? Some of these coils are not designed to work with the high energy ignition systems such as the FBO system. I'm sure you researched it thoroughly, but I'm throwing out ideas here.

Those wires have definitely got too hot at some point but they may not be past the point of no return just yet, although you will have to replace the connectors. I'm just wondering with your combo if there may not be enough resistance or maybe too much.

The male terminal looks like this.



If you use a pair of needle nose pliers to squeeze it narrower and it will then slide out.

and this is the female.



You will need to stick a small screwdriver/metal stick to depress the tab shown on the bottom of the picture. It will then slide out.

they are available at Napa

or at
www.happyterminals.com

Hope it helps.

Now the reason that wire burnt may very well be from too much current flow to the coil/ignition system. You don't get more power out without more power in.

You may want to use a relay to power the ignition system.

Capacitive discharge ignition systems don't require a ballast resistor. (They may talking about running with their CD ignition box).

I replaced the blue wire that was burned and I made some voltage checks:
Key @ RUN:
Bat: 12.8v
Coil +: 11.9v
ECU: both terminals 12.0v
Dist Connector: 1.85v
Cranking: No visial spark from coil wire

NO START. It did not even try to fire. I pulled my dist cap and all of the tips looked clean.
I am plannin on putting on my old Orange MP ECU and try to restart, but not until tomorrow night.

Any other suggestions are appreciated.

Thanks

MP distributors use stock pickups. That's behaving like one marginal and then dying. If you have a factory service manual I believe this can be tested.

I agree the ignition feed at the bulkhead is a
big failure point! I've had that problem before.
You did not mention what kind of distributor that you have.Not likely a mallory Unilite if you're still using the "box",but is still possible to run one.
If it is the Mallory Unilite,replace the electronic "eye" with a new one.

I am using the FBO distributor/ECU with the Mallory e-coil.

""MP distributors use stock pickups.""
When I tested the distributor connector when the key was at the RUN position, I only got 1.85v.
What voltage should I be getting at the dist pickup at the RUN position? Is it 12v or is it resisted down?

I have the appropriate voltage to all of the key components as shown above except at the distributor connector.
I believe the problem is either the coil or the ECU. I still have no spark from the coil wire to the top of the distributor.

I swapped out to the MP electronic ignition kit many years ago so my ignition harness is not a 70 unit. Does anyone have a diagram that shows what the blue wire (burned one in my picture) goes to on the MP ignition harness? My 70 manual shows it going to the dash lights and the key-in buzzer.

Thanks

Do you have another ECU you can try? I have had a few go bad and they quit working pretty quickly. The first one I had go bad the car started to act up like it was missing a little when I was driving it. I got it home and shut it off. I tried to start the car and had a hard time getting it to start and when I did it would not idle on it own and sounded like it was really out of tune. After two times of starting and dieing the car would not start anymore. I swapped out the ECU and the car fired right up without any more problems.

The second one I had go bad was like a light switch. I had driven the car for a couple of years with the ECU box and after a drive one day I parked the car. A couple of days later I go out to the garage to start the car and it would not fire up. After some trouble shooting I figured out it was the ECU box. With the new ECU the car fired right up.

So given my past experiences I would try the ECU first. If that does not fix it then it sounds like it is the coil.

Loco,
Both of those issues sounds just like what happened over the weekend. I do have a spare MP Orange ECU that I will test tonight after I do a resistance check on the pickup coil.

Thank you.

Can anyone confirm what the voltage at the pickup coil should be at the RUN position? Is it 12v or is it resisted down?

Thanks to everyone.

The test I'm remembering (and it's been a very long time) is for resistance through the pickup. Not voltage.

David,
I found a spec of 150-900ohms thru the pickup coil (which I am going to check tonight), but I was wondering what the voltage would be coming to the pickup coil with the key at RUN just so I can confirm that too. I guess I will know if it starts up that it had enough voltage.

I have 12v going thru two of the pins at the ECU harness but only 1.85v is coming from the ECU (I think that is the source) and getting to the pickup.

Thanks for the reply,

I don't believe you will not find a spec for voltage going to the pickup coil as the ECU measures a/c voltage generated from the pulses from magnetic distributor pickup.

Allen,
Thank you for the clarification.

Actually, I might be having some similar issues with my ECU. How do I test that thing out to make sure it's working? Thanks

Here is a diagram that may help you out. Of course you do not have a resistor so it would be just a wire across there.

Allen,
Thank you very much for the schematic.
The burnt wire in the above pictures appears to be the dark blue wire (tracer) #23. I bypassed the bulkhead and wired the two #23's together for the short term as both sides of the bulkhead terminals were damaged.
In my above pictures, there is a green wire right beside the burnt blue one. The schematic that you posted does not show a green wire in the #24 position. Does this just mean that my harness may be a little older/newer than your schematic? I need to trace it just to see where it goes.

Thanks again,

Here is a diagram that shows it, hope it helps!

http://www.mymopar.com/downloads/1970/70ChallengerA.JPG

http://www.mymopar.com/downloads/1970/70ChallengerB.JPG

Quote:

---

In my above pictures, there is a green wire right beside the burnt blue one. The schematic that you posted does not show a green wire in the #24 position. Does this just mean that my harness may be a little older/newer than your schematic? I need to trace it just to see where it goes.

---

Engine side goes to horns, pass side goes to horn relay, sometimes all that extra wiring gets people confused so i just blank it out.

MC: Yes and thank you.

UPDATE:
I checked the resistance at the coil pickup and it read 282ohms which is in the range that I found of 150-900ohms.
Then I replaced the ECU with my spare and no change, no spark from the coil wire. Then I took both ECU's to my local parts store and they tested each one 6 times and they were both tested as good parts.

Is my coil fried?
I checked the resistance across the pos/neg terminals and it read .4ohms. ???

Thanks again,

Do you have a part number on the coil? I have some specs for some of them but need the number to see if I have the right one.

If you can supply that and do the following and post back, we might find some info on it.

1.
Disconnect everything from your ignition coil
2.
Take your DMM, set to the Ohm or continuity setting, making sure you have the range set properly
3.
Connect the DMM between the (+) and (-) terminals on your coil. Note the reading.
4.
Connect the DMM between the (+) terminal and secondary terminal on your coil. Note the reading.
5.
Connect the DMM between the (-) terminal and secondary terminal on your coil. Note the reading.