So I’ve had my coil replaced with the MSD Blaster 2 and I have no spark. I am not knowledgeable about how these things are wired so my brother and I tried to copy the way the existing coil was wired. My truck is a 1976 F150 360FE.



I have a red and green wire going to the positive side along with a second wire (not sure the color). I have a solid green going to the negative side. There is a black wire with a female spade terminal and nowhere to connect it (pretty sure this is the problem).

 

Ok, here’s a follow up question. I found this part of the wiring diagram for my truck:




This shows a black wire between the coil and the dizzy. I don’t see a place for the black wire to attach. My dizzy has 3 wires coming out that go to a connector and then continue on to the ICM. The colors are orange, pink, and black. Can somebody show me where the black wire attaches to their dizzy?

 

It hooks up the same way as the old one. It is possible the coil is bad right out of the box. Check that all the wiring is still good and nothing came loose. It would be best to test if you are getting power to the coil.

 

Is this with a duraspark setup or points? You may need a different resistor giving power to the coil. I have a 360 that I converted to duraspark and have an MSD blaster 3 coil. it works great with an MSD resistor.

https://www.summitracing.com/parts/msd-8214

 

Also I believe MSD recommends to mount the coil in a more upright position. it looks like you've got it at a 45. I don't know if that makes a difference.

 

Thanks. My distributor is a Duraspark. I now think the problem is that the MSD coil requires an MSD ICM. So now I’m going to try to put the old coil back on. The problem is, I’m not entirely sure how the wiring works for the stock coil either. Right now I have two wires going to the positive side of the coil. One of those wires seems to go to the capacitor and the other one isn’t hooked up to anything.




Does that wire go to a resistor? I don’t think I have a resistor. Does the stock coil have to be hooked to a resistor?

 

You don't need an MSD box to run that coil.

 

Yes or the OP will join the club of exploding coils. MSD and Accel top the list for coil explosions.

 

The positive post on the coil must have 12v going to it during crank and run (ignition switch in the on position). There is a resister built into the wiring harness already for the 12 volts going to coil during the run mode.

During crank mode, you will notice on the starter solenoid there is an extra wire that sends 12v unresisted to the coil to increase voltage for better spark during cranking since the starter is reducing overall system voltage. Be sure that is connected.

The capacitor increases the spark voltage leave it connected.

The voltage to the coil is independant from the ignition system if the wiring has not been hacked in stock configuration. You can simply connect a jumper wire from the battery to the positive on the coil with the other wires disconnected from the positive terminal to trouble the issue. If still no spark, then it's in the DS2's hands.

There should only be 2 wires going to the positive terminal on the coil one being the condensor...not sure where that other black wire is going.

The ignition switch sends direct battery voltage to the coil during cranking and resisted voltage to the coil during run and the ignition switch generally fails in the run mode leaving you with and engine that starts in the cranking position and dies when you let off the key...which doesn't seem to be the case here.

As for coil position, I have recently replaced a failed coil that was laying nearly horizontal it's whole life on a 400m.....some 39 years of service that way. I do agree however putting an oil filled coil upright is a good idea.

If you want a coil that kicks azz and is cheap, use a stock tfi epoxy coil. They work great with msd also....just hit 23 psi boost on a 9:1 351w turbo engine no sweat.

 

Also, the DS2 box receives a 12v signal on the white wire during cranking that reduces timing, and a different 12v signal to the red wire on the DS2 during run. This is also done through the ignition switch. The voltage does not change here, the DS2 does the ignition timing retard or no retard internally depending on which wire receives 12v to ignite it.

For testing purposes, can run a jumper wire from the battery to either the red or white wire to energize the DS2.

 

A while ago I broke my starter relay and have been using a heavy duty Cole Hersee relay instead. It does not have a place to connect the brown “I” wire, so I left it disconnected and with a stock coil, the truck started without issue. Could this be the problem?

 

By the way, I had 12 volts at both the positive and negative sides of the MSD ignition coil with the ignition in the run position.

 

It should just boost the voltage when the solenoid is engaged....so it should still have spark/voltage to the coil without the wire connected as you noted with it starting with the old coil.

As mentioned above, it is possible you have a new dud. Msd coils just have lower lower resistance to boost voltage at the expense of making the ignition amp (DS2 or MSD) work harder. They work the very same way as a stock coil.

How are you testing voltage? Digital volt meter? They can read phantom power that has no amps due to a bad connection. Use a test light to be sure you have a bright light at the coil positive.

What I would do is remove all positive wires from the coil and run a jumper from the battery. If no spark, try a known good coil...it does not have to be bolted to the engine.

If still no spark, be sure there is 12v at either the red or white wire on the DS2...jumper if necessary. If still no spark the DS2 box may have failed by coincidence or was on it's last leg and the low resistance of the new coil finished it off.

I have been doing this stuff for many years, always soldiering and shrink tubing all electrical connections, as they are the primary suspect when troubles arise. Verify you have good voltage with a test light and leave it on the terminal during cranking. You can put the clip from the test light on the positive and and stick the probe of the test light into a ground to make it easier, the polarity does not matter.

 

thanks, I’m gonna check all that stuff tomorrow. I was using a voltmeter and a test light, but I didn’t try running a jumper from the battery.

 

Other things to try....remove wires from the coil and ohm across positive and negative. Wait a few seconds for the ohm meter to settle down. Should be between .5 ohm and 2.3 ohm.

Run a ground wire jumper from the negative on the battery to the vacuum advance nipple...have seen dizzy's lose ground to the engine...the DS2 box uses the dizzy for it's ground.

Also have seen wires break around the 3 wire dizzy connector.


One way to simplify things in the mind....if you have a dizzy, DS2 wiring harness, coil, and DS2 box sitting on a table, all you have to do is connect the ground from a battery to the dizzy body, and the positive from the battery to the positive on the coil and red or white wire on the DS2 box....spin the dizzy and the coil will spark if the components are in working order. BE CAREFUL! Wear a glove while spinning the dizzy....you can become ground to earth and get a nice ZAP!

Not saying you need to try this because it's already set up in the vehicle, just helping clarify how really simple this system is. I have a system like this on stand by when breaking in flat tapped cams on engines that will be efi...I use a carb and DS2 for simplicity and reliability to break in the cam, then install the efi so if troubles arise with the efi, the cam lobes are not in jeopardy if excessive cranking is necessary.