Car won't start immediately after turning off

[pbcrazy]

Like the title says, I've been having this since mid-winter but it seems to have gotten worse with warmer weather. Basically if I shut my car off (while it's warmed up), then wait 20 seconds-~10 minutes, it won't start. It either cranks very very slowly, or doesn't at all. I currently have my battery relocated to the back with an 150 amp fuse inline, and I actually blew that fuse trying to start it once. Things I've checked:

• CTS reads reasonable values for idle and when warm
• Lights stay on when trying to crank even if it won't start/Can listen to radio, etc. even if it won't crank
• Sometimes it will start if I jump the battery, but not consitantly
• If I wait long enough, it will always start (once it is cooled a bit)

To me, this seems like it's obviously a starter issue (the starter is likely overheating due to the exhaust being hot right next to it, and I should change the starter), however one of my friends swears it's the battery even though I can still run lights/radio/etc. when it won't crank (the battery was checked a year ago and was not 100% but still definitely fine to use). Any opinions would be awesome!

[walky_talky20]

150 Amp fuse is a bit light for the battery cable run. I'd probably upgrade that to a 250 Amp.

You would confirm a starter issue by making certain the starter has everything it needs during the no-crank situation. 12v+ from battery, 12v+ solenoid trigger, and a good ground to the starter case. I wouldn't be surprised if you have a lousy ground to the starter.

[ricekikr]

+1 on the ground. But i'd start with the battery ground.

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[pbcrazy]

Simple enough, I'll re-sand where my battery ground is, and I'll test the starter wiring. If I test on a cold engine, the voltage values should be the same as when hot correct?