[tony]

Installed a 428 in Dad's '66 Ford F250. The engine already had a duraspark dizzy from the 76 truck I got the engine out of; yes, it is a 428 and no it is not the original engine. I had a box and retrieved the wiring harness I needed. I also purchased a new MSD coil for duraspark ignitions. I connected the white wire to the start terminal. I connected the red wire to the back of the key wiring. Connected the coil using the factory wiring. When I try to start the engine, it fires but it will not keep running. I tried a different box--no good. I checked voltaged--Red at the box has 12 volts with the key on. When in the start position, the 12 volts goes away while the engine is turning, then returns when you release the key to the on position. The coil has 12 volts in the on position, then the voltage drops to about 9 volts during the start, then returns to 12 volts again. I don't know what to check. I need some ideas-----------

 

[pedal2themetal45]

To witch terminal did you attach it to at the back of the switch. It should be the run terminal. Sounds like it's not getting power after the swittch is let go.
Jus t a thought
Tim

 

[Mario428]

The white wire is used if using points. If you have the duraspark hooked up as a magnetic trigger than the white wire is not used.

The red wire has to have 12 volts at all times, run and crank position on keyswitch. Can be somewhat hard to find such a wire on an old Ford.

Explain how you used the factory wiring for the coil, which wire from the MSD goes to where.

_________________

<font size=-1>[ This Message was edited by: Mario428 on 4/20/06 6:16pm ]</font>

 

[dennis112]

Here is the schematic that I used for my conversion. I know that it works well:

http://www.mustangsteve.com/conversion.html

Other links that may help:

http://users3.ev1.net/~bmarr/duraspark_ignition_upgrade.htm

http://members.cox.net/joetrojan/

http://home.cfl.rr.com/mustangsix/Engine/duraspark.htm

_________________
Dennis

65' Stang

393 stroker, Toploader 4 spd, 3:50 rear.

Victor Jr. knockoff heads, 282S cam, Stealth intake, Bigs Stage 5 750DP, Accufab headers, Scattershield, Caltracs.

<font size=-1>[ This Message was edited by: dennis111 on 4/20/06 7:10pm ]</font>

<font size=-1>[ This Message was edited by: dennis111 on 4/20/06 7:10pm ]</font>

 

[dbiscayne]

The white wire is used with Duraspark too, it retards the timing during cranking.

You need two supply wires going to the positive side of the coil, one coming from the keyswitch (thats the wire downstream of the pink resistance wire) and a second from the 'I' terminal at the solenoid (it's the brown wire in your diagram). It sounds like you left this second wire from the 'I' terminal off and that will keep it from starting.
What happens is that during cranking the voltage from the key switch to the coil drops. With the wire from the 'I' terminal tapped to the pos. coil also it will make sure that 12 volts gets to the coil during cranking.

Not sure why you don't have 12 volts going to the module in the red wire during cranking, but if what I said above doesn't fix it try putting 12 volts to the red module wire from somewhere other than the key switch, it will work but when you turn the key off you'll have to detach this new 12 volt supply to shut it off, the key will only be there to turn the starter.

 

[tony]

The green wire from the duraspark harness went to the neg side of the coil. The existing red wire from the old coil went to the pos side of the coil using the factory coil plug in. I did try a direct connection to the battery for the power red wire and it did not keep the engine running after it fired. I do not know the condition of the trigger module in the dizzy since it came with the engine.
Question: The run wire at the key, does it have 12 volts all the time meaning cranking and run?

I figure it is one of two possiblities:
1. The red wire is in the wrong place but that does not seem correct because it did not make a diffeerence when directly connected to the battery.
2: I have a bad trigger module in the dizzy.

 

[dbiscayne]

I think I misunderstood the first time, you're saying it'll start while cranking but then shuts off when you turn the key back to run position right?
If thats the case I would think that the +coil isn't getting power or the red wire to the module isn't getting power when you turn the key to the run position, could be a bad key switch.
The key switch feeds power to two places, one to the module, and the other to the +coil. It sounds like your key switch is bad, works while cranking cause the coil gets power from the 'I' terminal on the solenoid and the switch is working while cranking but not in the run position, but if that was the case it doesn't make sense that it won't run when you supply power to the module straight from the battery.

Try this link to another wiring diagram for the Duraspark:
http://www.mustangsteve.com/conversion.html

 

[dbiscayne]

Just noticed that you used the exist. red coil wire for the new +coil wire. I'm not sure but it sounds like that wire is only supplying power during cranking, check it with your meter it should show voltage with the key in the run position. I'm pretty sure I couldn't use the existing coil wires when I set mine up.

 

[tony]

The coil wire is red/green stripe, it is the existing coil wire for the points type ignition. This wire has 12 volts when the key is on. The voltage drops to about 9 volts when the engine fires. You release the key, the engine dies and the voltage returns to 12 volts. I found the run wire at the key. It is also red/green for about 4 inches, then plugs into a wire that might be pink (old wiring). I connected the red module wire before the plug. All the diagrams I have seen use the existing coil wire. It still won't run.

 

[tony]

We figured out the problem. The plug for the red and white wires at the box are in one position but the plug that comes from the red and white connections are reversed. I thought this was strange but my '87 F250 plugs are the same way. We rewired the connection to match the box wiring not the plug wiring and the 428 came alive!!! Thanks for your help!!

 

[dbiscayne]

I hate it when that happens! Had a trailer light connection do the same thing to me- always the last thing to check.