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Hello All,

Working on my 69 Mach.  Originally an S code, but the original engine & trans long gone when I bought it, now have a 351W & C6.  Trying to get it started for the first time.  New MSD Digital 6AL tied to the fuse block ignition circuit, and since I believe the neutral safety switch is bad, I bypassed it with a jumper at the fire wall wire harness - seems to be sending the proper signal to the starter relay.  New battery, new heavy duty battery cables, starter checks out on the bench as being good.  Turn the key and all I get is a faint buzz at the starter relay (some call it the starter solenoid, located on the passenger side next to the battery).  I cross the two large terminals on the starter relay (from battery terminal directly to the starter cable terminal) and nothing at all happens.  Checked the ground at the starter and it seems fine.  Checked the ground at the firewall connected with a strap to the intake manifold seems fine.  Got a positive test light signal at the starter.  Starter just won't turn or even make a sound.  Tried another starter, also in good condition, same results.  The only thing I can think of is the battery is now weak and there aren't enough amps to do anything to the starter except show a positive test light.  Any thoughts?

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Yeah, first have the battery tested.  Or, connect a battery charger to it or jumper cables from another vehicle and see if it cranks or anything is different.  If your + and - cables and connections are good, then you are down to the battery or starter.  By the way, I never had any luck with the original style rebuilt starters sold at parts stores for these cars.  They usually would barely crank my 351W, sometimes not at all.  In the long run, I ended up with a high torque starter.

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Thanks everyone.  It was a bad ground at the battery, then a bad starter solenoid.  Took care of both issues and now it cranks nice and fires once, but wont start. Could it be the ignition switch is bad?

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Get a volt/ohm meter. When cranking you should get battery voltage (~12v) at the coil BAT terminal. After its started it drops to ~10.8v with the alternator charging. Since it fires it may be the line from the ignition switch C. It goes from C through the tach if you have one, if not it comes from C to the resistor wire and from there to the coil. That line is probably open. An easy way to test that is to temporarily run a wire from B+ to the coil BAT terminal, then crank it. If it stays running then it is an open circuit somewhere in that line. Use the ohmmeter to figure out where. If you need help with specifics on how to do that just ask.

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If you are doing voltage checks do not leave the ignition on for too long without the engine running, its the easiest way to burn out the coil.

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2 hours ago, unilec said:

If you are doing voltage checks do not leave the ignition on for too long without the engine running, its the easiest way to burn out the coil.

Yes I've always heard that, but I've never wiped one out. If the ignition is on and the points are closed, then the coil will be on. Any idea how long it would take to overheat the coil? Maybe 15-30 minutes (or longer) for a stock coil?? Anyone with any experience with this?

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Thank you both very much. I will try that idea to run the temporary wire and find the open circuit.   I  do have a tach and the MSD has an input for it,  but I didn't connect it yet.  Do I need to connect the tachometer to complete the C circuit? 

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2 hours ago, gnatsum said:

Thank you both very much. I will try that idea to run the temporary wire and find the open circuit.   I  do have a tach and the MSD has an input for it,  but I didn't connect it yet.  Do I need to connect the tachometer to complete the C circuit? 

Stop, don't do it. That diagram is for a stock system, and I wasn't paying attention. I missed that you had an MSD, and as you can see, there is no MSD box on the schematic.  Now it becomes more complicated, and I'm not an MSD expert, never having used one. What do you use to trigger the MSD? Describe how each wire is connected, then someone can jump in here and help.

 

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What MSD setup do you have?  An MSD ignition box and MSD distributor, MSD Ready-to-Run distributor, MSD ignition box and stock points distributor?

If your factory tach is still stock and has never been retrofit with modern internals it Will Not work with an MSD ignition box without an additional MSD Tach Adapter.  The signal from the MSD ignition box Tach terminal simply will not operate the stock tach.  Unfortunately, because the Ford factory tach is current triggered you will need the more expensive Tach Adapter , p/n 8920.  https://www.holley.com/products/accessories/tach_adapters/parts/8920

If you have one of those MSD Ready-to-Run distributors I don't know how the factory tach would be connected.

With an MSD ignition box be certain you have a 12V constant and a 12V ignition switched source.  The 12V ignition switched source needs to be in both crank and run positions.  I picked up my 12V switched source directly at the ignition switch.  The original wiring to the factory tach and the ignition coil will not used at all.  I left mine in place but it is not being used.

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Thanks.  I ran a new wire to the MSD from the old tan/brown coil wire, from the 4-wire harness at the firewall but it sounds like I'll need to run a new one directly from the ignition switch. The MSD receives power and ground directly from the battery.  The MSD then sends a feed via two wires to the coil. I also have a circuit run to the electric choke on the carb, separate from the MSD. There are feeds from the MSD for tachometer etc which are not yet connected. The unit is a Digital 6AL MSD electronic ignition. The engine was pulled from a 1987 Bronco and still has the electronic ignition distributor with no points.  The coil is also stock. 

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Jeez, and you didn't think it was relevant to tell us that you have a 69 Mustang with an 87 Bronco engine and ignition, that's now converted to MSD? One little change to an electrical system will make a difference...and this is a pretty big change. I suppose you've heard the IT expression "Garbage In, Garbage Out"? How could anything we tell you help without the facts? Good luck with FrankenStang. Don't mind me, walking away shaking my head muttering to myself.

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Jeez right back at you my friend.  If I had it all together I wouldn't have to ask for your help.  I'm sorry to have wasted your time. In respect of everyone's time, I was trying to keep my back story brief and mistakenly left out the origin of the replacement engine.  I do value the sage advice from you and others on this site,  so please forgive my incomplete description of my situation and continue to offer any suggestions you might have to help me out. I'm still very new to troubleshooting electrical problems and ignition,  please bear with me. 

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14 hours ago, gnatsum said:

Thanks.  I ran a new wire to the MSD from the old tan/brown coil wire, from the 4-wire harness at the firewall but it sounds like I'll need to run a new one directly from the ignition switch. The MSD receives power and ground directly from the battery.  The MSD then sends a feed via two wires to the coil. I also have a circuit run to the electric choke on the carb, separate from the MSD. There are feeds from the MSD for tachometer etc which are not yet connected. The unit is a Digital 6AL MSD electronic ignition. The engine was pulled from a 1987 Bronco and still has the electronic ignition distributor with no points.  The coil is also stock. 

If the distributor is one with a mechanical and vacuum advance and has the Ford OEM 3-wire connector it should work with the MSD ignition box.  Picking up the 12V switched power from the original coil wire is incorrect because that runs through the original resistor wire wrapped into the harness under the dash and through the factory tach.  That is unless you have changed some of the original wiring.  I don't know if the stock coil will work very well or last very long with the MSD.  I've never seen that combination.  Again, you will need an MSD tach adapter which I believe is p/n 8920 to connect your factory tach to the MSD ignition box.  Maybe double check with MSD on the adapter part number needed for an original current triggered tach.

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Good stuff, thanks. So if the 12v coil wire is not what I need to send the ignition signal to the MSD, where would I get the 12v ignition circuit from? Would I run a 12v ignition switched accessory circuit from the under-dash fuse panel?

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1 hour ago, gnatsum said:

Jeez right back at you my friend.  If I had it all together I wouldn't have to ask for your help.  I'm sorry to have wasted your time. In respect of everyone's time, I was trying to keep my back story brief and mistakenly left out the origin of the replacement engine.  I do value the sage advice from you and others on this site,  so please forgive my incomplete description of my situation and continue to offer any suggestions you might have to help me out. I'm still very new to troubleshooting electrical problems and ignition,  please bear with me. 

Its my fault for not asking for the complete picture BEFORE giving advice. I often assume people know more than they do. When I was 10, I had a pretty good understanding of how electrical things worked and hot wired my Dad's car just to see if I could. I didn't want to drive it- and I never told him. A friend asked why I didn't just make another key- and I never understood that attitude. Electrical stuff was cool and I guess that's why I became an electrical engineer.

I've had a Snickers bar and am back to my old self...that's my old grouchy self. I'll help when I can, but stay off my lawn ;) 

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32 minutes ago, gnatsum said:

Good stuff, thanks. So if the 12v coil wire is not what I need to send the ignition signal to the MSD, where would I get the 12v ignition circuit from? Would I run a 12v ignition switched accessory circuit from the under-dash fuse panel?

According to my reproduction Ford wiring diagrams, at the ignition switch there is a red-green wire that has power in both crank and run positions.  This is the power wire that goes to the tachometer.  The diagram also shows it splicing and going to the fuse panel.  I don't know what terminal it would be on the fuse panel.

Some people have connected the MSD box like you did and it works.  But, a long time ago a friend of mine did that on a Fairlane and had intermittent issues.  Sometimes it was fine, and other times it would start and die.

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1 hour ago, gnatsum said:

Good stuff, thanks. So if the 12v coil wire is not what I need to send the ignition signal to the MSD, where would I get the 12v ignition circuit from? Would I run a 12v ignition switched accessory circuit from the under-dash fuse panel?

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