I have an issue with my 84 F150 5.0 4x4.
I just changed the iginition module on the distributor which fixed one problem, but now I have another.
The truck starts fine and runs great. Once I have driven for 10 miles or so and stop the engine, and try to restart it immediately, the starter turns really slow as if the battery is dead. When I opened the hood and checked the battery, both the red and black battery cables were so hot I couldn't touch them. Once I let the truck sit for 10 minutes and tried starting it, it started fine....

Any suggestions,

Thanks!

 

Your starter solenoid, is it on the starter, or mounted on the fender???

 

Cables get hot for 2 reasons, high resistance or too much current. It not uncommon for a bad starter to draw high amperage when hot. The best thing would be to test the starter draw when its acting up and compare it to when its not, but that would require an inductive amp meter. Autozone or similar stores may be able to check that for you, but I'm not sure.

 

Back long ago, full-service gas stations used to be able to do this, too.

More recently, I seem to remember Sears offering to do this for free, too.

 

I'd clean your grounds first. A bad ground connection can cause a high draw. Had this problem with the Wrecker. Put a new starter in it, and it would turn slow as all hell and the cables would get very hot. I cleaned ALL of the grounds and that took care of that.

Plus it never hurts to clean the grounds and it's free

Edit: reading your post again, I'm thinking there might be something shorting out while the truck is running. That would cause the cables to become hot and drain the battery. Put a volt meter on the battery itself and see what the voltage comes up as the truck is running then report back. Battery sitting voltage should be around 12.5v charging more like 14.7v.

 

I will check the voltage on the battery, but one thing I did notice is that the cables only got hot when I tried to crank it while it was hot - and the starter was really slow turning. If I just cut the engine off and checked the cables they were cool.

 

If the starter solenoid is the thing that the +ve cable goes to from the battery, it is mounted on the fender next to the battery.

 

It's probably a bad starter, you could just replace it (cheap enough) or do a starter draw test

 

I just went through the same thing. The fact that both cables are hot makes it less likely that you just have a bad connection. The starter is most likely worn out. when i pulled my starter, it was obvious that the drive end bearing was shot. My truck is a manual transmission and i was unable to source the proper bearing, so i was stuck purchasing a remanufactured starter if i had an automatic, the bearing only costs a few bucks. I was pretty bummed because the rest of the starter was in great shape. The brushes and rest of the bearings were mint.

 

So it sounds like the starter. truck starts fine except when it is hot. cranks like the battery is dead and both cables get hot, they only get hot when cranking. Engine cools for 10 mins and it cranks right up.

Is the starter solenoid on the passenger fender also a possible culprit?

 

The Starter Solenoid could be, but it's not very likely at all with your discription.

Your discription suggests bad starter, cables, or bad grounds. Most likely starter. I suggest you have it tested.

 

your starter is getting hot ! do you have headers on the truck and if so then you need to wrap them to keep heat off of the new starter or the problem will continue ! also if your exhaust pipe is close to the starter it will do the same thing , wrap or insulate your exhaust around the starter and the starter will stay cooler and will work !

 

Take your battery to autozone or wherever and have it load tested - I bet your battery is getting bad. When the starter is hot it does have higher resistance - If the battery is getting bad, the voltage drops down when you put power to the starter. Since the starter needs the same power to start the engine, the lower the voltage the higher the current needs to be to generate the same power to the starter ( Power = Volts x Current) As the voltage goes down, the current skyrockets to the starter and starts to over heat the cables - I have seen cables melt out of the terminals at the battery.

Have them check your charging system too

 

Good suggestions so far. Starter, battery, cables. Autozone and the like may not be able to accurately test any of your components. All the chain stores here have gone to testers that only give a pass/fail reading. They sell more parts that way. If they test a battery and it says, "charge and retest", it has been my experience that it is a bad battery. Have a real starter/armature shop check the starter and repair it if necessary. It has ALWAYS been cheaper for me to do that than to by a rebuilt/reman starter. If the cables look original, replace them. They need it.

I had a hard start when hot problem once. I replaced the starter, then the battery, then an altenator to fully charge the battery. Each time I thought I had it fixed. On the advice of the armature shop, I ran a new ground from the battery straight to the starter bolt. Presto! More starting power than I had ever had in that truck. I slit the insulation on the still good looking original cable. Lots and lots of green crud and several strands of wire broken from corrosion. I should have listened to the armature guy and tried this first, but what did he know, right?

 

It isn't likely that both cables have gone bad at the same time, so the fact that both get hot indicates another, common-to-them problem. And, a bad connection raises overall resistance which lowers the current draw, so that isn't it. Similarly, low battery voltage reduces current draw.

The common denominator in all of this is the starter. If it has a bad bearing, which allows the armature to drag on the field, it will pull inordinate amounts of power - if your battery, cables, and connections are capable. And, since the starter will be running more slowly than usual you will have to crank longer. Either problem will heat the cables more than usual, but taken together the two will cause the cables to get quite hot.

Bottom line: Replace or rebuild the starter.