Problem Starting when Warm

[PJones96]

Is there supposed to be a heat shield for the starter?

https://www.autozone.com/batteries-starting-and-charging/starter-heat-shield/p/gm-genuine-parts-starter-heat-shield/1251499_0_0?searchText=starter+heat+shield

You think the starter is getting cooked and may be causing the starting issues when the truck's warm?

 

[movietvet]

They made starter shields for that purpose. The heat will swell the field coils and then the armature drags on them, causing too much starter draw. When happening, you can sometimes tap on the starter body to release inside and the engine will crank and start. That starter is close to the exhaust. GM had a problem and they installed a shield. there are after market wrap shields, too. I THINK that may be the problem. You said yourself, that when engine is cold, it starts normally and that your problems happen with a warm/hot engine.

You said the starter solenoid shot craps and that is the one part that is closest to the exhaust and the heat can and will accelerate the demise of the component.

 

[PJones96]

I bought heat shield wrap made to fit around the starter. Put that on. No change to what is happening. I read this on another post:

I've seen where an engine ground was missing and the negative cable was bolted to just a frame. The truck (late 70s Ford) was killing alternators and having slow cranking when hot. The entire drivetrain was grounded through the driveshaft to the rear end and back up through the parking brake cable. I was surprised that the Neverspark ignition system didn't croak.

SO this has me thinking I've got sad cable issues, meaning the negative on the battery. I'm going to check my cables after work today to see if that's the culprit. I don't have any other issues or symptoms of bad grounding but it seems plausible to me.