No Start...need help troubleshooting

[iBrent]

It's an '05 with the V8. It drove home from work this afternoon just fine. I get in it later to take my wife out to dinner and no start. Not even a click. As soon as the key gets the run position (even before trying to actually start), gauges start freaking out and lights turn off.

Bust out the voltmeter. Key in Off position, battery reads 12.5 V. As soon as the key gets placed in run position, not even trying to start, battery starts dropping like there's a short somewhere. Goes all the way down to 5 V. Remove the key, wait a few seconds, battery is back up to 12.5 V.

Figured I would start at the relay. Removed the starter relay, measured the resistance across the relay, its open like it should be. Applied 12 V using a trickle charger, the relay measured a short like it should be. So the relay is just fine.

I took a wire and shorted the two biggest terminals on the starter itself...nothing. No clicking, no motor noise, no crank, although there was some sparking on the wire when I touched the terminals. I figured it must be the starter. So I disconnected all the wires from the starter and now with the key in the run position, the battery stays at 12.5 V.

So its the starter that has failed right? If I remove it, can it be bench tested like they test alternators? Is it possible to just replace the solenoid if in fact that is the part that failed?

Next question...how do I get the starter out? I can see 2 of the bolts...how do I get the third one out?

 

[ExPlOrErImPoRtS]

see any broken wires for the starter follow wires over by oil drain area. Any wear through wires. my wire broke at starter when mine failed to start.

 

[iBrent]

see any broken wires for the starter follow wires over by oil drain area. Any wear through wires. my wire broke at starter when mine failed to start.

I saw the chaffing while I was down there last night. The outermost insulation has been worn through but the inner insulations are still good. I can clearly see red and yellow with no copper.

 

[matt0248]

Get a new battery and have the charging system checked just to be safe. Batteries fail sometimes unexpectedly, one minute it is fine the next bam, dead battery. The other possibility would be the starter itself. A hot starter will draw more amps than a cold starter. a good shop can do a starter draw test.

 

[waskly]

broken wire at the starter.

think the little one that kicks the solenoid over.

 

[imp]

broken wire at the starter.

think the little one that kicks the solenoid over.

But that would not draw the battery voltage way down, like there was either a short circuit, or the starter is locked-up and drawing a huge current. imp

 

[imp]

So its the starter that has failed right? If I remove it, can it be bench tested like they test alternators? Yes, it can.
Is it possible to just replace the solenoid if in fact that is the part that failed? Yes, the starter-mounted solenoid is replaceable. However, bear in mind the solenoid does 2 things: first, it shoves the starter's pinion gear into mesh with the flywheel ring gear, and then second, it closes a set of contacts which feed current to the starter motor itself. If one hears only the solenoid "click", and the starter fails to turn, then either the solenoid's contacts are not closing the circuit to the motor, or the motor itself has failed (assuming the battery and connections are OK). Battery voltage dropping way down as you say suggests either a very high current draw, more than normal, OR the battery is at fault, possibly having a high-resistance cell within it.

Next question...how do I get the starter out? I can see 2 of the bolts...how do I get the third one out? I haven't done a V-8 starter in an Explorer, but in Mustangs, I used a very long extension to reach the top starter mounting bolt, from 'way in front of the engine mount. imp

 

[waskly]

But that would not draw the battery voltage way down, like there was either a short circuit, or the starter is locked-up and drawing a huge current. imp

really? a dangling 12v wire wont draw current down? if its not touching anything you would get nothing, if its going to ground, i would say you would see a short to ground draw and voltage drop.

 

[iBrent]

Thanks everyone for your help. Before trying to remove the starter I figured I should eliminate the battery first as the culprit. I brought it to Autozone to get it load tested. It failed. As soon as a load was put on the battery the voltage dropped immediately.

I guess your first inclinations were correct (as usual)!

New battery, started right up.

 

[matt0248]

Glad we could help.