How do I load test a starter? '94 Ranger

[andyd]

If somebody knows, please school me. It is winter and the Rat is up to its usual tricks. It likes to spend the winter laid up. This time it is the starter. 'Zactly what, I dunno. Turning the key gets me a click. It is coming from the fender mt'd starter relay. The starter mt'd solenoid is quiet.
The starter is an exact copy of the original Ford gear reduction gear starter. I mis diagnosed a dead short as a bad starter and a 38$ new starter looked good. Rebuilding the starter would cost me more than that. The original starter worked but rattled like a maraca. In goes the clone. Both starters test fine. So does the relay and wiring. I put the starter on the fender and hooked it up to its wires. Turned the key and it worked. In the truck. nothin'.
The starter is hand assembled and is a breeze to work on. Even the original came apart easily. I swapped solenoids, no sweat, T25 screws. First casualty was the braid to the brushes parted on the donor. but removing the brush pack was a snap, tweaker screwdriver stuff. the armature and stuff looked OK. But after I pulled out the armature, I saw a ball bearing stuck to a magnet. That explained the rattle. That and a bad nose bushing. My Franken-starter consists of the clone's reduction drive, field magnets, housing and brush pack. I used the original solenoid and armature . The clone's had a whiff of smoke. I'll follow up with my results after I put the starter back in.

 

[gman2304]

AZ will load test it for free.

 

[eljefino]

If you know the internal resistance of your battery (newfangled testers know this) you can do the math if you catch it at its lowest voltage level during cranking. Could also use an inductive pickup ammeter.

As for your diagnosis... if the starter is stuck on something mechanical like a seized engine, the headlights will dim. If it's not even trying to work, your headlights will remain bright when you hit the key.

 

[mk378]

You could have a bad engine ground. Measure voltage from battery negative post to the engine block while someone turns the key trying to start. It should stay much less than a volt.

Also you want to measure that voltage is actually coming out of the fender solenoid. When worn out, they will click but not make contact.

 

[NYEngineer]

Put a volt meter across the battery leads and crank the engine. Watch the meter and see what the voltage drops to during cranking.
If you get a click and the voltage takes a nose dive, it's most likely the battery. If you get a click and a very small or no voltage drop, it could be a bad cable or connection.
Check voltage into and out of the fender mounted solenoid, see that you get 12 volts on the pull in wire when the key is turned.

 

[andyd]

I've re-done the circuit twice. I have 12.56 V at the 10awg stud on the relay. When I use a screwdriver to cross to the little stud for the key, nothing. I would be fine with crossing the solenoid if the starter cranked but it doesn't. I was seeing sparks on the battery connection at the starter. I thought it was a loose connection at the starter, it wasn't. It could possibly be a wonky solenoid, grounding when it gets pulled in. Engine is free too, BTW. Holy Moley I just took another look at the clone's shiny armature. Then I saw a burn mark, or at least a really hot spot. 6 segments of the commutator are showing signs of smoke leakage. The franken starter bench tests fine, The battery snaps loudly when I short it. Metal melts. Battery is fine. Its been on a minder and is about 6 months old.

 

[dishdude]

Take another look at that battery.

 

[mk378]

Do some of the tests, any of the tests, suggested by people trying to help you here. The test where you turn the headlights on and watch for them to dim when you turn the key is a good one.

If you see sparks, there's a bad connection or a short there. It is not normal.

Does the starter itself also have a solenoid wire, or only the big wire from the fender mounted solenoid?

If it's a single wire starter, measure voltage at the starter from the live wire terminal to starter ground while turning the key. If you don't have voltage, find out where it is being lost.

Some Fords have a fender mounted solenoid in line with a two-wire starter with internal solenoid. This system requires both solenoid wires to go live when the key is turned.

 

[andyd]

I tested the be-jeezus out of stuff. I eliminated the NSS on the clutch and I tested that and found it good.

My Franken starter works! Rat starts like it used to, but hasn't lately. I noticed that the starter was working longer than usual before it stopped working entirely. Looks like I let the smoke of the armature. As for the solenoid. I dunno, but the old one works great.

"Some Fords have a fender mounted solenoid in line with a two-wire starter with internal solenoid This system requires both solenoid wires to go live when the key is turned." This one has a fender mtd "solenoid" just like every Ford I've ever had. For clarity, on the Ranger station forum, we have designated the fender thingy as the "starter relay" Which it is, but was always called a solenoid. As I had stated in my long post, I have no trouble shorting a solenoid, so that wasn't an issue. So of course it works fine. Total cost in parts- 44cents for some toothed washers. And beaucoup time