Engine wiring harness help
Thread Starter
Racer
Joined: Nov 2004
Posts: 422
Likes: 0
From: Owensboro Ky
Engine wiring harness help
I'm installing a new engine harness (69 vert) and not sure if I need to connect the yellow wire that bolts to the starter. The schematic show this wire connecting to the starter and then running up and connecting to the coil. I'm running a MSD system and in my mind don't think this yellow wire is of any use. One concern is that the yellow wire connecting to the coil also has a white wire spliced into it going back to the fuse panel. I hope this makes sense and someone can help.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
The yellow wire provides 12v to the coil during cranking from the starter solenoid. You probably should have bought a harness converted to HEI so you get 12V at the coil always instead of the ~6v through the stock resistance wire. Likely now someone spliced the white wire you speak of to get 12v at the coil to make the MSD work. If it's not too late I send it back and swap for an HEI ready harness.
Thread Starter
Racer
Joined: Nov 2004
Posts: 422
Likes: 0
From: Owensboro Ky
It's a new harness from Lectric Limited that is original to this year car but has not been cut. I guess what I'm asking is, if the MSD box provides the power for the MSD coil then I don't need to even hook the yellow wire up to the starter or coil. Which brings another thought, were should I run the positive switch wire from the MSD box to make it active on the ignition key.
Thanks in advance for any input.
Thanks in advance for any input.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
All the diagrams and instuctions r at the MSD w/s.
Yellow wire not needed - was used to bypass ballast/wire resistor to allow full batt (12V) to coil for start up and was opened once selinoid de-energized by ign sw. Just cut off connector and folded back then taped for insulation at the coil end on my '74 with MSD6AL. U can do this at starter end also.
MSD box controls all coil voltage now. BTW i'm using the MSD Blaster II coil and suggest this with the MSD box over a stock coil.
U need to follow the instructions with the MSD box but it does splice into the ignition wire from the switch with a smaller gauge red wire - this powers the box output on and off even though it has a separate larger gauge red wire to the batt+ for power (the heavy gauge black goes to batt neg-). That orange wire from the MSD box goes to coil pos+ and smaller black wire conntects to coil neg-. The last small gauge white wire goes to dist (points/amplifier).
Ok this will be different for different equipment. As i'm using an MSD dist in my '74 and the white is not used. So u can find most configurations at the MSD website if ur instuctions are not useable for some reason.
MSD box controls all coil voltage now. BTW i'm using the MSD Blaster II coil and suggest this with the MSD box over a stock coil.
U need to follow the instructions with the MSD box but it does splice into the ignition wire from the switch with a smaller gauge red wire - this powers the box output on and off even though it has a separate larger gauge red wire to the batt+ for power (the heavy gauge black goes to batt neg-). That orange wire from the MSD box goes to coil pos+ and smaller black wire conntects to coil neg-. The last small gauge white wire goes to dist (points/amplifier).
Ok this will be different for different equipment. As i'm using an MSD dist in my '74 and the white is not used. So u can find most configurations at the MSD website if ur instuctions are not useable for some reason.
