Hello all, I recently purchased an F100 Ranger. It has a 351M engine. The truck has no key, only a makeshift set of 5 wires that plug into wires under the dash to start(and work gauges). I attempted to install a bezel and key in the dash. everything seemed to install correctly, however after my install the engine won't turn over.....nothing but silence. I tested the battery with a multimeter and it seems to have a good charge.
Any ideas would be appreciated, befroe I go replacing! Thanks!

 

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In all those wires you should have a red/lightblue stripe wire. This is the wire that leads to the neutral safety switch(or clutch switch) and then to the starter relay.

Another one of those wires should be yellow I believe. This should be the hot wire from the battery. If you jump the yellow to the red/lightblue, what happens?

P.S. I just looked in your profile and see that your truck is a 1970. The wire colors I mentioned are for later year trucks, so they may not match. Go out to the starter solenoid on the inner fender and see what color wire you have on the "s" terminal of the solenoid. This is the color wire you should be looking for.

If your hot wire is not yellow, get a meter and figure out which one is hot all the time from the battery.

 

Thanks for the reply, my truck is quite a patchwork of parts from other vehicles, oh....and rust! I will look at the wire as soon as I get home. Thanks again.

 

I found the yellow, and red/blue wires, right where you said, and where my wiring diagram showed. I jumped the two and nothing. It seems as if my starter is underneath the engine, near the oil pan, is this right? According to my wiring diagram it is, I am not used to this, don't remember this loacation on the Mustangs I have worked on. I cannot find the solenoid, any ideas?

 

Your wiring should be somewhat similar to this. Make sure it's all hooked up like this. You are correct, the starter is on the passenger side of the engine beside the oil pan.

starter relay in the diagram above = starter solenoid (same thing, different names).

If all the wiring in the above diagram looks good, take a small wire and jump terminal #3 to terminal #5 in the diagram above. Make sure the truck is in neutral. It should crank.

The wire on terminal #5 should be the red/blue that is at the switch. If the yellow wire at the switch is hot, and you touch it to the red/blue, it should crank. Make sure someone hasn't changed transmissions and did not hook up the neutral safety switch. If they didn't, or it's bad, then there will be a break in the circuit from the key wires to the solenoid #5 wire.

 

Thanks for the diagram! Nothing happened when I jumped the two wires. I traced with my meter back to the solenoid. I suppose I damaged it when trying to install the ignition.
I replaced the solenoid, and whalah, back to the grinding noise. This is good and bad for me, I was able to get the ignition installed correctly, I think, but now maybe my starter is bad? The battery has a good charge, my gauges work, but the engine won't turn over, it just makes a sort of grinding sound.
Can someone confirm this grinding sound might be my starter? It seems like a PITA to get to.

 

If you hear a large thunk and then a grinding noise, it does sound like the starter has a problem.

Most of the time, the gear mechanism on the end of the starter is bad. A common name other than starter drive gear is "bendix". The bendix has a one-way clutch bearing inside it. This is so the starter can drive the flywheel, but the flywheel cannot drive the starter. The reason for this is to prevent the engine from ruining the starter if someone is still holding the keyswitch to start after the engine has started running. It can go bad and the starter will not be able to turn the engine.

 

Thanks for confirming this! I have replaced the solenoid, voltage regulator, and am in the process of instaling the new starter, if this doesn't fix it, I don't know what will. All of this parts looked VERY old anyway. Let cross our fingers for a successfull crank!

 

Almost everything has been replaced, starter, solenoid, volt. reg., and some wires. The truck just won't start, I turn the key and get a click/thunk.

 

Get someone in the truck to help you by turning the key while you do some testing with the multimeter.

Put the negative of the meter on point #2 and leave it there for the next few tests.

Put the + of the meter on point #1. Try to start the truck while watching the meter. If the voltage goes way down when it makes the thunking noise, then there is something wrong with the battery. If the voltage stays near 12 volts, go to the next test.

Put the + of the meter on point #3. Try to start the truck. If the voltage goes way down, then your + battery cable is bad. If the voltage stays near 12v then;

Put the + of the meter on point #6. You should have 12 volts here when the key is turned. If you do not, there may be a connection problem at point #3 or point #6. You said the solenid is new.

If you have 12 volts at each point in the above tests, then move the negative meter lead to the engine block. Find a shiny place to get a good ground on the engine. Put the + lead of the meter on the + of the battery, point #1. Try to start the truck. If the voltage does not stay at 12v, then your ground cable is bad.

 

I was able to get my girlfriend to turn the key while I tested, when she got home from work. I didn't realize that 12V was needed at the starter to turn the engine over. I have 12V leaving the solenoid(yellow wire), but when she tried to start the truck my meter read 3-5V at the solenoid from the red/blue wire.
I will continue tom., man thanks for sticking with this, Staunton isn't that far, when I get this truck road ready I owe you a beer!..Or two,..or three!

 

Just remember, the current flowing through the wire is like water flowing through a water hose. You are reading the pressure of the water with your meter. If you have a problem that is dropping the voltage to 3-5v, then it is the same as having the water hose kinked somewhere.

That is why you need to turn the key while taking readings. A water hose will have lots of pressure(same as voltage) if you are not using water(even past the kink in the hose). When you start using water(trying to start the truck) is when the kink in the hose(bad connection in the wiring) will show up.

So that's why I had you start at the battery, and work your way around to find the "kink" in the wiring. When the voltage is high, you are before the "kink" or bad connection, and when the voltage is low, you are after the "kink" or bad connection.

Sounds like you have found a problem between the yellow wire and the starter solenoid. The next place to check is the yellow wire at the keyswitch area. Put the meter on the yellow wire at the keyswitch, and the other lead on a good ground. Try to start the truck. If the voltage stays high at the yellow wire at the key area, you know the wiring is good from the yellow wire connection at the point you are testing at the key area. If you find this is the case, then I would start suspecting a bad connection in the red/blue wire. A good place to start looking is for the neutral safety switch. If you have a manual it will be on the clutch pedal. If you have an automatic, it will be on the side of the tranny.

 

Spent the day with the family, I will troubleshoot more tomorrow. Wouldn't you know I walked by the truck this morning and thought, what the heck, I'll try and start it. It turned over, and over but wouldn't start, so I let off the ignition. I tried a second time after that and same ol thunk. This truck is ornery!

 

Sorry it has taken me so long to reply. I do not have 12V at #6. I have 12V at the solenoid where the positve cable from the battery attaches, but nothing on the other side of the solenoid when a crank is attempted. I assume from your last post this means a bad solenoid? I have replaced it, and can replace it again(it's a cheap part). I was getting a thunk, and the engine actually turned over once, but now I don't even get a thunk.