Help with Ford 3930...no crank

[Harry in Ky]

The spade on the starter solenoid is always hard to access. I have a number of "home made" jumper wires (short lengths of wire with crimp on terminals on one end and just 1/2" of wire stripped on the other end) Male, female spades, different size ring terminals, etc. I take one with a female spade and push it onto the solenoid. The wire is long enough to reach around and "flash" to the battery positive starter post or connect to a remote start button. Easy to work with.

 

[Jason280]

Any reason to think it's not the starter solenoid st this point?

 

[blehmann]

If you are putting power to the solenoid spade and it engages and the starter turns, it isn't the solenoid. More likely a dirty switch or something else keeping full voltage from getting to the + side of the solenoid.

 

[Jason280]

No, I couldn't get to the spade...I manually jumped the main terminals.

 

[blehmann]

I'm not understanding what pulled the Bendix in to the ring gear if you are saying that you by passed the solenoid.

 

[blehmann]

Let me reword that. I haven't been into my 3930 starter yet so I'm not sure of the set-up. They are all basically the same though. If you were able to jumper to a post on that starter and the bendix engaged and cranked the engine, the starter is functional. Your problem is somewhere upstream on the wire going to the post that you jumpered power to. It could very well be a relay with badly arched contact points. The click you hear is probably the relay closing. The lack of starter relay engagement is because not enough power is getting through the high amp side of the rela

 

[TractorTech]

Still betting the PTO switch or the relay.
The PTO switch could be out of adjustment.

 

[Jason280]

I'm not understanding what pulled the Bendix in to the ring gear if you are saying that you by passed the solenoid.

I have 11.8/11.9v going to the ignition terminal on the starter solenoid. My plan was to simply apply 12v to this terminal with the wire removed, but couldn't access it...its pretty well blocked by the plastic shroud around the solenoid and the filter housing. So, instead of applying 12v to see if the solenoid/relay closes, I simply applied a jumper wire to the main solenoid posts.

The click you hear is probably the relay closing

No, the starter solenoid is not clicking (or making any noise). The relay I can hear closing is the one in the last two pictures on page 1...its some sort of electrical relay, but not sure what it controls.

 

[Harry in Ky]

That's the start relay. If it clicks when the key is turned to START then I'd say the key switch and safety switches are working. Relay contacts are bad or the wire from the relay to the solenoid spade has a problem.

OR the solenoid is bad. The jumper wire connecting the spade to battery positive would have told you that.

 

[blehmann]

I don't think that the solenoid is bad. It started the tractor. Solenoids are either good or bad, no in between. I'm assuming that when you used the 8 gauge wire, you robbed power from the large lug on the end of the starter. If the solenoid has two spades, one is positive input and the other goes to ground. Placing a wire across the two spades would create a short circuit if the positive terminal is powered because the only load would be the resistance of the 8 gauge wire. Touching a hot wire to the negative side of the solenoid would also create a short circuit. You have a problem with the wire or with something in-line on that wire that is reducing voltage or blocking it. As I said earlier, the easiest and first place to check for me is always the ground cable. It is a quick check that probably fixes at least half of the no start issues on equipment that doesn't get used daily.