Well, my 04 5.3 3v was running fine Sunday, go outside yesterday, turn the key and all I get is a clunk sound.

I metered the battery, and it was at 12.4 volts. I charged it back up to 13.5. Still got a clunk (not a click from the relay, but a clunk from the starter). I switched out the starter relay in the inside fuse box, still got a clunk.

Took the starter and the battery out, and hooked up jumper cables to the battery and starter. The shaft would push out, but wouldn't spin when jumpered.

For verification, I took the battery and starter to Advance to have them tested. The starter and battery both tested OK. The starter acted as normal, the shaft pushed out and spun. But the guy admitted the tester doesn't test the solenoid, just the starter.

I reinstalled everything, charged up the battery to 14 volts, and metered the starter while the key was being turned to start. I got the loud clunk again (definitely coming from the starter motor and not the solenoid) and it was receiving about 10.5 volts with the key in the start position for 5 seconds.

So now I'm stuck with what else to check out. Individually everything seems like's it's in GWO, but there's something somewhere not right when it's all put together.

Any ideas on what to check next? I'm really getting frustrated. Thanks!

 

Volts isn't a measure of how much charge is in a battery, volts = water pressure in the hyro analogy. If the battery is functioning properly, it should show a constant voltage of around 12.4v when the truck is off. When you crank it the voltage should drop, 10.5v doesn't sound unreasonable. Then when the truck is running and the alternator is charging you should get a reading in the 13.5v range. I'm guessing the 13.5v was with the battery charger hooked up? If so, your battery is functional (no bad cells) but that doesn't mean you charged it up enough. You could eliminate the guess work and use jumper cables and a friends truck.

The solenoid is just a switch that makes a connection when the hot wire gets juice, so if you have a good charge on the battery, the starter motor is operational, but you're just getting a pulse when running through the solenoid then that's what I would check.

Test the solenoid by turning the key to ON and bridging the + and - terminals with a well insulated screw driver you don't care too much about. You might need to bend the screwdriver a little, some auto manufacturers have a piece of plastic between the two I am assuming so you don't do this wrng and melt your eybrows. Keep your face as far away as possible because it will spark when you first make contact. Truck should fire up if the solenoid is good.

 

Frank,

which positive terminal? there's two: the S terminal and B+ terminal.

 

S stands for Start. Its the wire that runs into the solenoid that ultimately closes the circuit from the battery to engage the starter motor. Your screwdriver is replacing that function. B+ is battery positive and B- is battery negative. If the screwdriver works, you know the solenoid is bad and not holding the circuit closed when the ignition sends juice to it.

 

When I jumpered it, the starter just clunked. This was with the key in the on position and the truck being jumped off another running truck with a voltage measured at the battery connectors of the dead truck at about 13.5v.

Does that sound like a bad solenoid or starter?

 

It sounds like the starter motor is jamming. Especially if it was continueing to test at a constant 10.5v when you were turning the key but getting no movement - that means the motor was drawing current. Inside your starter motor you've got brushes just like any electric motor. Sometimes pieces of the brush crack off and get down into the windings and jam the motor. They could have dislodged when you took it to the parts store for testing but eventually it jams again.

If you're feeling industrious and its not a sealed unit you might be able to open the motor up, replace the brushes (have to do some digging for replacements), and clean the debris from the windings. That's what they would do at a starter/alternator rebuild shop. On my DD I just go buy a new one, but when I'm working on vintage motorcycles and a new starter motor costs over $500 I always rebuild.

 

it looks like a sealed unit, there's no screws or bolts at either end of the starter housing. I can remove the solenoid from the starter housing, but that's about it. And the replacements they sell include both the solenoid and starter, so I'm assuming they're meant to be replaced at the same time.

 

OK, finally got it figured out.

The strap that connects to the + battery terminal was a tiny bit loose, like a 1/4 of a bolt turn loose. I dissembled, cleaned, and reassembled with red thread lock and everything's been fine for a week now.