Alright, time to bite the bullet. I did not want to start a new thread about this issue, but other threads are not very helpful. I have a 1990 F-250 4x4 with a 460 and ZF5, but according to another thread I read about this issue, it's common with a lot of OBS Fords from '87 to '96. Basically I drive the truck somewhere, far enough to get up to operating temperature (no overheating issues), then shut her off to do whatever I need to do. I come back not too long after, say 10-20 minutes, and it struggles to start. It flat out did not start until I let it cool down for about 45 minutes, and one time I played with timing to make it start. It at first sounds like a dead battery, a bad alternator or a bad starter, but I replaced both the alternator and battery as soon as I bought the truck. I am not eliminating the possibility of the starter, but the previous owner said it was only a couple months old (verified by receipts). I saw a response on a thread that suggested heat shielding, but I bought one of those heat shields from Autozone that wrap around your starter, and that didn't do much. I had the truck idling for a good 10 minutes, which warmed it up a little bit (not operating temp, needle was barely on the "C"), and when I shut it off and tried to start, it started but struggled to. Should I go with a solid metal heat shield, or are there any solutions you guys would suggest? You are welcomed to post any theory or guesses you guys may have, anything will help, thank you!

 

Lots of hard start threads in the archives.

For example, what your describing sounds like hard to crank, or a labored crank.

My F-350 had both symptoms, hard to start and hard to crank..hot.

The hard to start crank was a bad ground cable at the block from the negative post of the battery, the negative cable on the big block also has a grounding clamp midway on the way to its mounting location the block.

Problems that I addressed for the hard to start hot issue was install an oil cooler (it had been removed, it's an "air over" cooler, not the type that's a heat exchanger with engine coolant), cleaned injectors, adjusted timing on a new timing chain.

At least it's MUCH better.

The other truck had a dramatic improvement with new injectors, pricey, but there you have it, well some of it.