It's one of those weird seven lug F250's, which would later be called a F150 with the HDPP. It's a 5.4 truck and I think for the question at hand it's easier to just think of it as a F150.


Apparently it hadn't been driven in a couple months. The owner drove it a few miles, it ran bad, the CEL began to flash(engine misfire most likely), they shut it off and then it wouldn't restart.

This truck is the most rusty truck I've ever worked on, I could probably pull the box off with no tools. So I'm trying to get it running without buying more stuff than needed.

The first thing I did was check battery voltage, it was 9 something, deader than dead. I put it on a charge for a couple days and it seems to have come back to normal voltage. I tried to start the truck, I get a clunk at the solenoid and sometimes the door locks lock and unlock quickly(Goofy stuff like this usually make me think a ground is bad somewhere). I cleaned up the battery cables and cleaned up the connections at the solenoid, no change. I jumped the two big wires on the solenoid, nothing. I went underneath to check the positive wire at the starter, it was corroded through and broke off the starter.

I put on a ford factory replacement positive cable on it. It connects to both big wires on the solenoid, the battery positive, and the two wires at the starter, just like the original. I was hoping this would be my fix since the old cable was clearly bad. No change. Same thing happens when I try to crank, thunk at the solenoid and nothing happens. I again jumped the two big wires across the solenoid, nothing. Doesn't even spark.

If I jump across the 2 big wires at the solenoid shouldn't it crank over? I tried it with the key in the run position but shouldn't it crank regardless of what the key is doing? Does the fact that nothing happens say the solenoid is good?
All of the positive cables between battery and starter and the solenoid are new. There is ground that goes from battery negative to the starter body and it looked fine but I didn't take it apart.

If I check the battery negative to ground cable and it checks out fine have I eliminated everything but the starter and therefore the starter must be bad?

But then what caused the engine misfire? What caused the battery to be run down to 9v? Why the broken positive starter wire?

 

You are part way there !!
My fist question is , how do we know the battery is capable of anything?

Here is one way to find out.
Turn the headlights on. Are they what we would call normal brightness?
If no either the ground from the engine to sheet metal is no good or battery is low.or no good
If yes, take a hammer and tap the starter a few times in case one of the brushes might be hung up.
Next , if you still get no action , just take a screwdriver and make a connection between the large terminal on the solenoid that comes from the battery and that small terminal on the solenoid. You should hear and feel the solenoid close and the starter motor should run. If you get no action when you make that connection between the small terminal on the solenoid and the terminal coming from the battery, either the solenoid is questionable, or there is no ground for the solenoid to work (sheet metal) .
If you now hear the solenoid work the starter if OK should operate, if not starter has a problem.

 

Before I found that the positive starter battery cable was bad I had been trying to start the truck with the battery charger on it with the 75amp boost setting. Obviously we know now that wasn't ever going to help anything because the starter connection was bad. Now that I replaced that cable I'll throw the charger back on and see if it changes anything, I think that would eliminate a bad battery, also I'll check to see if headlights and all other electrical systems seem to be working. Also I'll jump from positive to the small switched terminal and tap on the starter.

 

Just a side note,
75 amp boost is not enough to really supply the power the starter requires to crank over that engine.
Starter requires at least 150 amps. You could get false info if battery is defective.

 

The rapid door lock/unlock and/or anti theft lamp flash-clicking relays under the dash with ‘key on engine off’ or during cranking attempts are indicative of low battery conditions. Could be power distribution/ground etc, but you never stated the batteries age (?) or weather it was load tested or a static meter reading taken with the results after it’s recharge. A simple lighting visual check as hanky mentioned works pretty well to check for voltage drop out, or a meter reading for voltage across the battery terminals taken both before, and during a cranking event will prove out the battery fairly quick. And, you never mentioned a boost assist with another vehicle with a good set of cables. Also in agreement with hanky,, you need more boost amps for cranking, more so if the battery is going South..

 

It’s a big 900or so CCA battery, don’t know the age but I wiped it down and it looks pretty new. I put the booster on and did the above mentioned tests, nothing. I took the starter off and tried to test it with a pair of jumper cables and an extra jumper wire to trigger the solenoid off the hot. Nothing, couldn’t make anything happen. I took it in and they tested it and they couldn’t get anything to happen either. Although I was skeptical they knew what they were doing I bought a new starter. 140$ for the cheapest one in stock. I put it on and now the truck starts and there’s no overt misfire and no CEL.

 

Thanks for the update.
Just think, you will probably forget everything you did before all the things you repaired cause anymore problems.