Alright fellas I'm getting my butt kicked on my brothers 01 SD 7.3. I've never had much luck up top so I'll stay here. Truck won't start. It barley turns over. Ok, check batts, they show about 12.5. Charge all night and this morning showing a shade over 14. Give it a go and it spins for a half a second and acts like its dead. Showing about 12-12.5 on the batts. Pull his and replace with my red tops and it's doing the same thing. Checked all grounds and they're good. The ground to the block was absolutely filthy so I cleaned it real good and same thing. Check hot lead to starter and it's a little rusty, but not corroded. Here's where it threw me for a loop. The black plastic piece on the solenoid spun some when I removed the hot leg to the starter. I've never had a starter do that on me. He can buy a starter, but I really don't want to just throw parts at this thing.

Here's a pic of the black piece on the solenoid. It's the piece where the posts from the solenoid come out of.

 

check for voltage while cranking at the batteries, then across the starter solenoid on the fender, and then across the solenoid on the starter (the one you posted).

with the exception of the batteries, all readings should be near zero volts. if not you found your fault.

You can also check for voltage drop across the cables. there should be none when energized but I have seen cables corrode under the sheath.

Richard

EDT: for reference, when I say check "across" a solenoid I mean the big terminals when the solenoid is energized.

 

Thanks Richard. I'll try that when I get some help.

 

Batts were at about 12.5 and dropped to around 8 when hit. Same for both solenoids.

 

Do the batteries recover when you let off the key? Do your Optimas act the same way? If so, I think the starter is shot (shorted internally).

 

Yes. The optimas are still in it. That's what Bill and I were talking about earlier, I just wanted to double check. The starter is soaked in oil, it doesn't surprise me something has shorted in there. As always, thanks guys!

 

It's normal for the voltage to fall as a load is applied, but for it to dip that low, I think you have a bad starter, plus I don't think the solenoid on the starter should spin like that.

 

yea... I am thinking the starter is toast....

Richard

 

Hey look at that, I was able to rep you guys!

 

starter is toast Todd. we just went through the same thing last night on a 08 5.4 truck. started it up to move it, and 15 minutes later nothing. dead as a doornail. put the welding cable jumper cables on it to the mack, and nothing.
one of the guys got under it with a hammer to give it a whack to see if we could get it into the garage, and the solenoidal spun just like yours is doing.

put a new starter on it and it fired rite up.

the old starter suffered a meltdown between starting and the 15 minutes it sat before trying to start it again.

 

Thanks Tom!

 

I just went thru this on my 97 a few weeks ago. Same issues and all. Solenoid spun too, but I just replaced the solnoid, not the whole starter. ($250.00 here!) $50 for a solenoid, and back on the road.

 

Good deal. I still haven't pulled the starter, maybe I can go this route.

 

Just an update here as I forgot to yesterday, but the new starter did fix the problem. As if there were doubt at this point! Lol

 

Did you end up doing the whole starter or did you just to the solenoid?