I've been fighting this problem for some time - after my car is up to temp, and especially in warm weather, the car really struggles to start. The classic symptom of extremely slow cranking (reminds you of a dead battery). I thought perhaps the stock starter couldn't keep up with my 10.5:1 comp engine, so I replaced it with a high-torque unit with the same result when the car is hot.

I have tried adding the starter wrap but to no avail. Anything else I can try? I'm running long tubes on the car but it was the same symptom with shorties as well and a different engine.

 

Buddy I have the same issue with my motor. I've tried high torque starters and they never seemed to work any better. Maybe it could be a cheap battery w/o many cranking amps, i know mine is the cheap dyek or deka.. whatever lol. But i have the same compression and I tried the heat wrap, messed with the base timing and got all the same result.

 

You mite want to check out the wires that go to your starter. I think when the enigne is warm up one of that wires that go to the starter must to heat up and have an effect

 

The battery cables especially the positive can cause this problem.Check to see the difference in flex a couple inches from the terminal and say at the mid point of the cable. If it's harder near the terminal it's evident there's internal corrosion.
It would help to compare with a new cable.

Heat causes the wire/cable insulator to dry up and crack allowing it to corrode internally.

 

Just wanted to post back with a result:

I checked all the cables and made sure they weren't corroded anywhere - they weren't. I cleaned all connectors, and it still started hard/wouldn't start when warm. I decided to replace my Duralast Gold battery (700 CCA/ 875 CA) with an Optima Red Top battery (825 CCA/ 1000 CA) and that definitely solved the problem. I drove the car around and got it nice and warm, and made sure that it was under the same conditions as when it wouldn't start. I stopped the car, turned it off, and immediately tried to start it right back up - it fired right up.

Might be worth getting a Red Top battery if you run an engine similar to mine and are having starting issues. Thanks for your help all.

 

My 09' Cobalt is my DD.

I have a red top Optima in my Camaro. A yellow top in my 86' Silverado which I don't use very much. No problems starting either one.

 

Thought I'd update this with the real fix: I did replace the battery with a redtop as mentioned, and it seemed to work - however, the real fix was moving to a larger gauge starter wire and large ground wires. I actually now have 0 gauge starter wire and 0 gauge grounds on the engine and battery. I no longer have trouble starting the engine at any temperature (cranking) and other electrical 'pulsations' in the vehicle are at a minimum from what they use to be. My suggestion to anyone with the issue I had is consider replacing the starter wire at least and make sure all your grounds are good. If you have an 86 like me, that wire is probably original and is just plain shot.

 

Sounds like a good idea.

Same issues, had a Red Top but went to Duralast Gold 1000CA and same problem. Terminals and cables from batt are all new (+/- 1yr).

Heavier gauge to stater, seems legit.