Starter "Heat Soak" - common or possible failing (new) solenoid??

[Fixit]

Just got done with a 180-mile run at varying highway speeds with #9365. Did a lunch stop after a 80 miles stretch (about an hour), a fuel stop at the 100 mile mark (about 10 minutes) - not an issue/problem with a restart after either.

After the final 80 miles I pulled up to the house, shut it down, shlepped in some stuff, and went to move the car (approximate time 20 minutes). No Start.
(The fuel pump pulsed, gauges swept, even heard the Coyote underhood start request relay trip...everything as it should be except no cranking.)

I let it cool down to where the sidepipes were warm/touchable, and slid underneath as best as my beer storage reservoir would allow.
My 1st thought was "Did I leave enough slack on the solenoid trigger?? Maybe the engine torqued and pulled the wire out of the terminal?" Nope, still connected... however
I nearly burnt my hand/fingers on the solenoid & starter... They were HOT!

I let it cool down another 15 minutes, twisted the key, and Vroom. Popped right off as it always has.

What's your thoughts guys??

There's nothing in tight proximity to the starter except the engine block... or at least in comparison to a Small Block Chev with headers (I know all about heat soak on those!) How's this thing getting so hot?

[edwardb]

Nothing like that's happened with mine. First time anyone's posted about it and a Coyote as far as I remember. Looked at your build thread and was reminded you have straight tube headers, so pretty much the same as my 20th Anniversary. I'm as 5,200 miles, including to 300+ mile days during the Texas spring event that was fast and hot. No issues. Does seem a little concerning that your starter and solenoid were that hot. But I have nothing to compare to. Haven't reached out and touched mine anytime soon after driving. Suppose there could be something with your Motorcraft starter. At least that's the one I assume you have. Although sometimes Mike provides a different one from what I've observed. Also assume you're seeing normal operating temps. I rarely see mine about 80 C. Including today on a stop and go cruise in about 85 degree F humid summer day.

Just a flyer here -- any chance something is going on with your clutch bottom switch? Maybe out of adjustment or intermittent. That would do the same thing, e.g. everything with the Coyote system would work except it won't crank. Would be curious to know if when it won't crank whether there's actually +12 volts at the small terminal of the starter solenoid.

[PaulProe]

Make sure you have an A+ or better ground between the battery and the starter. If you're using the chassis as the common ground, I install a flex cable between one of the starter mounting bolts and the frame, making sure the paint/powder is scraped away under the connection. It only takes less than 1 ohm to affect the starting and heat is not your friend, it only makes things worse.

[frankeeski]

Check to see if the alternator is "hot" as well. If it is, the problem is with the wiring to the alt and the starter is a secondary issue.

[Fixit]

Update...

I think it was a fluke, or I've got an impending doom problem.
I've taken several trips since the "incident", all of which got the car fully up to temp, and never a hiccup with a restart.

I drove 30+ miles one-way to a pals house, shut it down and risked flesh to confirm the temp of the alternator and starter/solenoid. The alternator was warm/engine temp/call it normal underhood hot... The starter was a little warmer, not blistering, but uncomfortable to touch for more that a few seconds. (i'll have to zap them with my IR thermometer).
- Checked the clutch switch... mechanically nothing has moved, it's tight, right where I set it months ago. Electrically it makes/breaks every time, and "makes" with about 1/2" of clutch pedal travel left.
- Just for S&G's I pulled and reseated the starter related Coyote fuse & relay several times to wipe/clean the contacts.
- Broke out the meter and tested at each "break" in the start request circuit... ignition switch, clutch switch, request fuse, request relay... all have +12 at the proper time.

This really sucks... as now I've got this nagging WTF in the back of my head that's totally "reset" my confidence in the car. Can you push start a Coyote? <G>

[Fixit]

07/14/19
Approaching the 1000 mile mark, and no further issues with a hot start. I've made multiple trips (short and long) with a lot of "on purpose" shut off's & restarts... nothing.

I intend to do an oil change & filter at 1000, and at that time I'll hedge my bets. I've got an old asbestos welding gauntlet that I'll sacrifice as a wrap for the starter. It can't hurt, and I'm under there anyway.

[Fixit]

While I was under #9365 doing its 1st oil change, I had to take a look at the starter & solenoid... my confidence in the car was reset to nearly zero, and I don't like that!

First... Removing the starter from a Roadster with a Coyote & FFR headers is a breeze! Basic tools to remove the electrical connections, and a 14mm on a 12" extension w/ a swivel and it's out in 10 minutes.


https://youtu.be/njyB6pWZigE

Backtrack... I'm guessing I inadvertently "fixed" my problem when I was poking around under the car. I tugged/pulled on the solenoid trigger wire, which "tightened" the post into it's bracket. The terminal was tight on the post, but the dang post wasn't tight in the bracket!

I'll guess again that the terminal post is a "D-shape", or maybe a "star" and its pressed into the bracket and staked in place. Mine wasn't tight, and my tugging on it bound it (by rotational friction) tight enough to maintain enough contact to work. Enter road vibrations & heat/expansion and it worked itself loose again.

Enter the MIG, two quicky zap/tacks, a minute with the Dremel, and I've got a post that'll never work loose again.

110926110927110928

[Mark Eaton]

I always like it when a little MIG welding saves the day!