Hot starting issue

[mickpep]

I have an 89 vintage 5.0, fuel injected engine in my roadster. I built the car basically according to the manual. The battery is in the trunk, using the battery cable that came with the kit.
I installed a battery cutoff switch. I'm having problems with starting when the car is hot. When I first start the car, it turns over strong.
After getting it up to full temp it won't start on its own. It will start from a jump though. I have already checked the solenoid, alternator, starter, and battery, all good.
Thanks in advance for comments and help

[Avalanche325]

Make sure you have a good ground in the engine bay. Some people do one right on the starter. The next thing would be to upgrade the cable from the battery.

[68GT500MAN]

Run a larger cable from the battery to the starter. I even did this with my GT500 and it made a huge difference in hot starting.
Doug

[Jeff Kleiner]

Battery cables. The provided 4 gauge is marginal and becomes more so with the long run. Changing ALL OF THEM (battery + to cutoff, cutoff to solenoid, solenoid to starter, battery - to chassis and engine to chassis) to 2 gauge will make a huge difference.

Jeff

[j.miller]

What is the CCA's of your battery ? The hotter things get the more amps they draw....battery could be good, just not strong enough.

[avgjoe]

I had a similar problem and tried all the stuff Jeff mentioned above and relocated my "fender" solenoid back to the fender and away from the header. But to no avail. It would start cold every time! I finally pulled the starter (an old lo-torque 25# brick) and found the starter drive gear was hanging up and binding. It would engage the flywheel but wouldn't turn. This explains the big drop in voltage at the starter that I thought was bad cables/connections/grounds/...... I put a hi-torque starter (8#) in and haven't had a problem since.

I could have probably put in a new lo-torque starter and it would have worked fine. The hi-torque starters have a different sound to them but that's the only drawback I'm aware of.

My problem is probably not the typical cause of starting problems but something to be aware of. I would do all the other things people mentioned first because those are things that need to be correct for any starter and are often overlooked.

[mickpep]

Thanks to all of you that responded. I appreciate the information and will make the changes.

[Avalanche325]

I used Moroso cables. They have connectors that work like a compression fitting. They work very well.