F250 1985 351w
Ran fine yesterday - today, starter spins very slowly and gear does not appear to be meshing at all.
Battery at 12.5 volts Starter was tested at NAPA 3 weeks ago and worked fine.
Fender relay is working but don't know if it can only work partially or if it is a go no go situation.

Any suggestions would be appreciated.
Thanks,
Chuck M.

 

It sounds like you have a bad battery, a bad connection or a bad solenoid. Here are my suggestions:

• Battery: Just because you have 12.5 volts doesn't mean the battery is good. First, 12.5 is low as it should be 12.8. Second, you need to check it when you have the key in Start.
• Solenoid: Bridge across it with a known-good jumper cable. That will prove it if is bad or not.
• Cables & connections: You can easily have a bad cable or connection. Put your volt meter in the 20 volt scale and put it from the + battery post to the solenoid's battery post and try to start. If you see any voltage at all you have a bad connection. Then do that on every single connection and cable, including the grounds.

 

Gary,
Thanks for the quick response!
The battery is only 3 weeks old so I'm hoping it hasn't gone south already. I will retest with key on though
I did bridge the fender relay with a jumper cable and got the same sounds from the starter=seemed like slow revolutions but no gear extension.
I will check all cables as you suggested tomorrow. It does sound like it is getting juice, but just not enough.
Chuck M.

 

12.5 isn't fully charged. You may have an alternator problem.

 

Last time I checked alternator (3-4 weeks ago) it was putting out 14.5 volts. As soon as I get this thing running, I will check again.

 

Ok. Just check the battery voltage while you are cranking as the 12.5 when idle is low.

 

I've ran down my battery trying to crank my truck. Cranking often and not letting it run long enough to recover the charge from the alt.

I've read these staters have a high draw add to that the alt isn't the strongest.

Double edged sword.

 

There are better starters, like the Permanent Magnet Gear Reduction units that Ford went to later. And there are better alternators, like the 3G units that, again, Ford went to later. So our trucks are working with old tech that was improved later and can be retrofitted if wanted.

 

Going bone yard picking today for a pmgr. I hope the 89 crown Vic ltd had/has one. But it'll be something to do at least.

Didn't mean to hijack.

 

Well guys, sometimes the simpleist tasks end up being complicated. Verifying the connections I am attempting to run down the battery ground cable and have yet to find the end. It is buried somewhere under the engine but not easily, if at all accessable.

Two notes about this truck: It is four wheel drive and has a meyer snow plow mounted on it. Both of these items are preventing any reasonable access from underneath. There are also about 20 vacuum hoses in the way. I'm trying to pull those aside but fear I will have to have to disconnect these (and document where they all go) could take some time. the negative cable from the fender solenoid seems to go to the same place as battery ground.
Question' what would be the down side of getting new cables for these and attaching to a different ground location? The ground for the snowplow motor is attached to the alternator/smog pump mounting bracket. Would that be an acceptable solution?

One other note: I found a loose formed piece of sheet metal under the right side exhaust manifold = all rusted and loose. I'm guess a heat shield but not sure and there isn't one under the left side exhaust. Any ideas?

I do appreciate all your help and advice! Although a senior citizen by age, I am a newby to any serious automotive stuff. Please bear with me.
Thanks again,
Chuck M.

 

You can bypass tracing the wires. On the positive cable you should put the red lead of your meter on the rear post of the solenoid and the black lead on the post on the starter. If you test post-to-post you are testing the two connections and the cable at the same time, so a good reading means there's no problem there but a bad reading means further inspection or testing is needed.

On the ground test from the negative battery post, not the cable's clamp, to the engine block - not the end of the ground cable. Again, if that passes by showing no voltage to speak of then all is well. But if there is significant voltage you will have to test or investigate further.

As for another ground cable, where would the battery end of it go? Once you've proven the battery connection good you could put another cable on, but not until then. And that bracket should be a good ground.

 

Gary,
Thanks again - I will test those cables as you outlined right after lunch.
Also, I have a correction on my previous post - the other "ground" cable I said ran off the solenoid is in fact the starter cable! My bad, guess I had a brain cramp.

The additional battery ground cable I was referring to would be replacing the current one that I can't access - if it proves to be bad. My thought was to cut it off and run new ground cable - Only if the existing ground proves to be bad after testing.

 

So it would go from the battery's negative post to the engine somewhere? That will work, but on many of these trucks there's a ground from the engine to the frame which runs the lights and other such. So if your original ground is bad then you probably won't have a good ground to the frame. Watch for that.

 

Gary,
First cable test battery positive to incoming solenoid post reads 0.6volts when starter circuit is activated. If that is excessive, what does it mean? Bad Cable? I checked the cable for resistance when I was cleaning up the connections and got zero ohms.
As for testing solenoid rear post to starter, I'm going to need longer wires for my multimeter.

One other thing - hooking up the meter from battery positive to rear solenoid got actual battery volts - does that make sense?

 

That's a bit more voltage drop than I expected. And if that's the only drop you have then it isn't a big problem. But, if all your connections and cables have that much drop then you'll be losing a lot before the starter. I'd go ahead and do more testing, and you can use jumper cables to bring the starter connection up to where you can get to it. And then decide what to do.

As for what it means, it could be anything - the connection at the battery post, the cable to connector connection internally, etc. But, with the equipment most of us have we cannot measure the resistance of the terminals, connections, etc. The resistance is so low that our meters can't measure it. And, the resistance effectively changes when high current hits it and it heats up.

And battery voltage is what you should see from positive to the rear stud on the solenoid. You have full battery voltage on one side and effectively ground on the other as the starter motor is a very low ohm, like well less than 1, to ground.