New to the forum, and new to the f series. I had a bronco for several years and just picked up an 81 f150 with a 300 5 speed and 4x4. Its been highly abused. Its probably not worth fixing but i'm at least going to learn a few things. Interior is really bad and the ignition is destroyed. You can see the cylinder with part of the broken pin inside. I dont think its connected either. I know the truck runs because the friend i got it from had a friend who had it running this week. We couldn't get it running and he had no idea what the guy did. What they had been doing to start it was pushing on this wire above the steering column that i believe hooks into the ignition at the top. Somewhere along the lines it quit starting consistently ith that method. It would not crank. Sometimes it would do a single click around the starter solenoid (Not like a dead battery noise), but most of the time nothing at all. And then sometimes if would actually turn over and try. Now i did try jumping the starter solenoid and it was normally during those times that it would start. But not every time and it wasn't only when i did that. When it did try and turn over i could get it to run on starting fluid for a few seconds. To be honest, im not sure that it had gas in it at the time. Since then, i did add gas and i never could get it to try again. Voltage going into the ignition coil was around 7 volts. I'm not sure if the ignition was on or off when i checked at the coil because i dont think it actually turns off. They were removing a battery cable to get it to turn off before. I do plan on rewiring the majority of the truck because it appears to be in rough shape. Is there a way to bypass the ignition switch? Also, what do you guys think the problem is? Obviously i will be replacing the ignition switch but what other components may be at fault here? I'm waiting on the Haynes manual to ship. It seems to be shorting out somewhere because most of the time it doesn't do anything when attempting to start. I am mechanically inclined, but still relatively new at this. Sorry for the long post, any help is much appreciated.

 

I would repair the column or get another from the junkyard. I would not bypass the ignition switch on a permanent basis. The ignition switch is mounted on top of the steering column behind the dash. You can take the u-bolt clamp loose o the bottom of the dash and let the whole column drop to get to it easier.

For now till you get all that straightened out, you should be able to jump point #3 to point #5 in the diagram below and it should crank as long as you have this jumped. If you have power to the coil at this time, and fuel in the carb, it should try to start. The solenoid should click each time you jump 3 to 5

If it won't crank with 3 and 5 jumped, get a testlight or voltmeter and put it on point #6. You may need a helper because while you are testing for voltage at #6, jump #3 and 5.

If the testlight lights, but it won't crank, check your large ground wire.

If the testlight does not light but the solenoid clicked, move the testlight to point #3. While holding it at #3, jump 3 to 5.

If the testlight stays lit, your solenoid has a problem. If the light goes out, you have a bad connection at #3, or #1 at the battery.

 

Ok thanks for the info. I was a little confused at the starter solenoid and then i realized that i had the other style (replacement?) https://static.cargurus.com/images/s...1600x1200.jpeg

What are the point names on this style? Also i will be using a voltmeter/multimeter. How many volts should point 6 be reading?

 

Point #3 on your installation is on the RH side of your solenoid. Look at the diagram Franklin posted, Point #3 has the battery cable between the battery & solenoid and this is also where the wires connect that feed power to the rest of the truck (I see 3 or 4 such wires in your picture, the gray ones).

Point #6 connects the solenoid to the starter motor which looks to be on the LH side of your solenoid.

Follow Franklin's diagnostic steps and report back with the results.

 

Forgot to mention: not my picture. Just found it to make it clearer. I will try this once i get home this afternoon. One more thing, franklin said to jump 3 and 5. Where is 5 on this new setup?

 

5 is the small-gauge, red/light-blue-stripe wire, it's shielded with a black boot & plastic conduit on that picture. Remove that wire from the solenoid and test on the screw-thread terminal.

 

Ok thats what i thought thanks.

 

Ok i'm a little confused. quickly tried it after school today. Jump 3 and 5? Well i did and i made a pretty strong constant vibrating sound in/on the starter solenoid. I've always been shown to jump 3 and 6. I'm not sure. I'm going to try it again tomorrow morning but just wanted to make sure i was doing it right. Didn't have time to get a meter on 6 but i will then.

 

It is hard to say with out a meter on it but sounds like a bad connection or low batt. volts.
Dave ----

 

Yes, you have a low battery or a bad connection at the battery or the large ground wire.

What happens; Just sitting there the voltage is 12v everywhere in the system. But somewhere in the system there is a restriction in the flow(bad connection) or the battery is low. There is enough flow through the restriction in the system to run the solenoid(3 to 5). So when you jump 3 to 5, the solenoid activates and puts the starter on the battery(3 to 6). Once the starter is in the system it needs A LOT of flow. The restriction(bad connection or low battery) cannot support this high flow to the starter, so the voltage drops across the problem area. Once the voltage drops, the solenoid opens back up, there is not enough voltage in the system(3 to 5) to hold the solenoid in.
Once the solenoid drops out by itself, the starter has been taken out of the circuit, the flow reduces, and the voltage rises back up enough to where the solenoid comes back in by itself(3 to 5). The it starts all over again, the voltage drops, the solenoid drops out, the voltage rises the solenoid comes back in again. It does all this very rapidly, that is where the buzzing sound is coming from.

 

Ok. Battery might have been low. Trickle charged it overnight and then tried jumping 3 and 5 this morning. I didn't get any vibration. Small spark but no attempt to crank. Number 6 was reading just under 12 volts while jumping the others. I suspect the large ground may be at fault. Would i check resistance on it?

 

When you jumped 3 to 5 this morning with a fully-charged battery, you say there was no fast clicking sound nor vibration, that's good. Small spark is OK. But the starter didn't attempt to crank over? When you made the electrical connection, did you hear/feel the solenoid making a single kinda-large click or thunk as you applied & removed the jumper?

 

No i dont think it did. Its definitely not now. I also dropped the steering column and replaced the ignition switch. That didn't change anything. Also tried to hotwire it from pos battery to pos ignition coil. Some sparks but thats it.

 

I wonder how much of this truck is original, since F150's were not available w/a 5 speed until 1988.

 

Check your large ground wire. Or take a large jumper cable(one side of a set of jumper cables) and hook it to the battery negative and a good clean metal place on the engine block. Then jump 3 to 5 again. If it still does nothing, I suspect the starter has a problem.

You can take the starter out, get your jumper cables, hook the negative to the starter case, touch the + to the large bolt on the starter, it should jump and turn. If it doesn't, then definitely something wrong with the starter.