Starter problems please help.
 

Hi, I have a 1997 F150 XLT 5.4L Automatic with 220,000 miles on the dash. I'm having an issue when starting the truck, it will turn over some times and then not turn over for like 10 times, then turn over fine again off and on, and whats crazy is it will turn over every time when the car is jumped.

My alternator is fine and I have full power. I don't have an alarm/security light issue.

So far this week I changed the battery, bought new positive and negative cables, new Starter relay on the firewall, and checked all the grounds.

With a test light I checked all the top leads on the Starter relay on the firewall, when cranking and they are strong, but the bottom wire that goes to the starter is weak when cranking. Again if I give the battery a jump, it starts right away, no issues.

I don't believe the starter is shot but I'm going to change it tomorrow, if that's not the culprit what do you guys think it is, the PCM?

Why will it turn over every time with a jump, if there is no power issues?

When you say starter solenoid do you mean the solenoid that sits on top of the starter, or the starter relay on the firewall? Could be the starter going bad if all of your connections are good.

Starter relay on the firewall. I will edit that, didn't know the exact name. And I hope that's the case, I will be doing that in a couple hours.

This may sound funny, but another thing to check is the cables for the starter and connections. These trucks are apparently known for corrosion and wire/connectors falling apart causing issues.

I will check that, but the truck starting all the time with a jump is the odd part here.

I guess it could be something with the relay, it's hard to tell without seeing it being able to test everything myself. I did notice though, you replaced the battery, did this issue happen before? I ask because if not, you may have gotten a battery with too low of a CCA rating which is why it would start with a jump no problem.

The issue happened before the battery, no corrosion and I changed the starter and the car worked fine for a week and now the same thing.

This is crazy how could it work fine after putting in a new starter and back to the same thing?

Does the relay need to be changed, but if the relay was bad the truck wouldn't start at all right?