84 TPI No crank, No start Hot
 

Hi all, I need some help/ideas.
My 84 w/TPI all stock will crank strong and start when cold, will not crank or start hot. Wait a while until it cools off and it will start again.

I replaced the starter motor and added insulation around the starter and solenoid, still the same problem.

I'm not sure where to look next, any ideas????

Thanks for your help.

Since you already replaced the Starter we will remove it from the list for now, How old is the Battery and have you had it Load Tested cold and hot? are the Battery Terminals Clean and Tight at all their Connection points. Here in FL we are hard on Batteries, when problem occurs if you put a test light on the crank request line and try to start is there Voltage there?

Battery terminals clean and tight, Battery tests at about 60%. Not sure where to find the crank request line...…..

The Smaller wire connected to Starter Solenoid.

With Heat comes Resistance a 60% Battery Hot might not be Enough for the job if the Cables or connections are weak.
60% Good is still 40% Dead. so when it happens Try Jump Starting from another Vehicle with Good Jumper Cables see if things Improve.

Electrical resistance goes up with heat. You said it tested 60%??? I have never seen a test like that. It should cycle a load against it and monitor the voltage drop.

Easy test is to roll into an Autozone or similar and ask them to test it IMO. Should give a test result of good/bad. It may not have enough strength left to turn over a hot starter.

Do you have an 84 with the Crossfire Injection or an 85 with the Tuned Port Injection? TPI is usually the latter.

With that said, check the cables and ensure you have a good ground on the negative. Check for breaks in the insulation near the starter and check to make sure the connections on the solenoid are clean and tight.

Yes, you are quite right..... It is Crossfire Injection.

Ground (-) recently replaced, Starter/solenoid and insulation recently installed.
Last post suggested to check the Battery, Advanced Auto Parts says Battery rated at 550 Cold Cranking Amps and tested at 490 (good).

I'm still scratching my head.

So here are a few things I'd check.

Too much timing when hot will cause hard starts. Check your base timing.

like said above, resistance goes up when hot so it could be the wiring. Ohm out the large positive to the starter and see what its resistance is. Check cranking voltage when cold at the battery and starter. You should be above 10.5 volts ideally.

Finally, 550 cca seems low for the battery in these. I'm pretty sure mine is rated at 650. Could have the wrong battery in it. Easy way to check would be to try jumping it with another car when hot.

you also said you have insulation around the starter? I've found that that generally doesn't help if you have a heat soaking problem if that is in fact the issue.

All good stuff, gives me a direction to pursue.

Thank you.

You may want to test for voltage at the starter solenoid when attempting to crank the engine over when this problem occurs. You'll need another person to help you out of course, but I'm curious to know if the starter solenoid is seeing 12V switched power when the condition presents itself.

Hi, I have a 84' also but the problem happened on my 69'. the small wire that goes on the starter solenoid is the ignition wire. On my car, farther up in the harness was a point where the wire was bent and the copper was broken in the plastic insulation. When cold, the wire made contact and the starter would turn. When the wire heated up, (through engine heat) it would pull apart and the starter would not turn. Give it a look. Good luck. Joe