Starter connection question

[Al_C]

Take a look at the photo (please). Pretty standard stuff for most other than yours truly. Here's today's challenge: I have three red wires (RF Harness), a "battery" cable (it's actually coming from the master cut off, prior to the 250a fuse) and the Coyote starter cable off the PCM.

I have three posts on the starter solenoid. The documentation is fuzzy enough that I'd like some verification/correction on what goes where. That's where you come in! The RF manual shows a black cable going to the bottom right (looking from the front of the car). Black - must be a ground, yes? Then the four red cables (three from the RF Harness and one from the battery) go to the outboard, or bottom left post, and the coyote cable goes to the top post? Or will everything go boom if I do it that way?

[edwardb]

No please don't wire it that way! Several things.

(1) The "starter solenoid" pictured in the RF schematic would be much better labelled as "firewall starter solenoid." Don't confuse the wiring shown there with the terminals on the back of the starter itself. For a number of years these cars have been built with a firewall starter solenoid. That's how Ford did it for years. With the change to the smaller PMGR starter with an integral solenoid (what you pictured) the firewall solenoid is technically no longer required. Many still use it, for several reasons. But especially for your Coyote setup with the start function controlled by the Coyote PCM and PDB, I wouldn't use one.

(2) Only two of the terminals on the starter are used. The large one (bottom one in your picture) is +12V from the battery. The smaller one is the start wire from the Coyote harness. The other large terminal is an internal connection for the starter and doesn't get any additional wires. Not every starter has a third terminal exposed like that.

(3) You can attach the three large wires from the RF harness to the large post on the starter if you like. Along with the +12V from the battery. Technically that will work. But it's not real neat IMO and typically the wires don't reach that far anyway. If you're using a master disconnect on the firewall, under the dash, etc., that'd be a better location IMO. Or use a binding post or bus bar.

[Al_C]

Thank you, sir! I knew there was a reason I posted this. You can sort of see in the photo that I got the red wires (and sheathing) to reach, but you're right - it's messy. I'll pull that out now. If I can connect them to the junction (like a single pole bus) that would work much, much better.

[AC Bill]

The starter is grounded already, via the block, but it can really pay off, to run an additional ground strap off one of the starter mounting bolts, to the frame.

[edwardb]

The starter is grounded already, via the block, but it can really pay off, to run an additional ground strap off one of the starter mounting bolts, to the frame.

Absolutely agree. I always have a ground cable off one of the starter mounting bolts at the bell housing plus one on the block itself. The Coyote has a nice threaded boss in the front lower PS that's perfect for the block ground cable.

[Al_C]

Thanks for the tip on grounding. I’m on the road a lot this week. I’ll check that out this weekend!

[Big Blocker]

Agreed . . . extra ground cables at the starter are a good thing . . . BUT NEVER, EVER connect a ground wire to one of the starter terminals. Ground cables need to be connected to "mounting" bolts only.