I recently acquired a 1985 F150 2wd AT with the 300 I6 for free. Owner said the starter just stays on even after the key is turned off. It has sat for an unknown period of time. Replaced the starter solenoid, now won't turn over, it tries but acts like there isn't enough juice to do it.

Checked hot wire from key, has 12 volts when at start, 4 volts when at run, 0 when locked. Replaced the ignition switch, still have the same voltages on the hot wire at the solenoid. Not sure if this is normal or not now.

I took the starter to autozone and it spun right up. Cleaned it, the contacts on battery, solenoid, and starter. Made sure the hot wire to the starter was not touching the starter housing, which seemed to be the case at one time judging by the burn mark on the connector. Hooked up another truck to jump it (for full voltage) and wouldn't do nothing.

Checked for a battery drain with the key off as stated in one of the stickies, I disconnect the neg connector on battery and put the DMM from neg post to neg battery connector, I get 12 voltage.

Now for the questions, should there be voltage on the hot key wire at the solenoid when key is in the run position? Where do I look to fix this? Should I be getting voltage when testing the ground on the battery when everything is off? Could I have a fuse somewhere that is blown?

I have had the truck for two days really, so recommendations you guys have would be truly appreciated. Been looking around but I haven't found anything more than solenoid or ignition switch problems.

 

Just to clear this up, if you followed the instructions in the stickie, it says to use a testlight, not a voltmeter. The test won't work with a voltmeter.



MAKE SURE THE TRUCK IS IN PARK OR NEUTRAL Make a small jumper wire and jump #3 to #5 and see if it will crank. If the key is in run it might start if it cranks.

 

Can you hear the solenoid click when you turn the key to START after your starter
re-installation? If so, are you sure the engine isn't seized? I believe it's a 15/16ths" socket
that is needed on the bolt holding the vibration dampener to the crankshaft, you might see if
the engine is even capable of turning.

I had a crankcase fill up with gasoline once that caused a no-turn symptom.

 

So the test will light a bulb, denoting power, but won't show up on a DMM? That doesn't make sense. A DMM or a bulb should both work equally well.

Things to do in the morning:
1. make sure engine turns
2. try jumper wire technique
3. attach DMM like in battery drain test, then disconnect the other positive wires on the positive solenoid terminal. Hopefully one of them will be my trouble source singling out which way to go from the solenoid. (signaled by the change in battery drain voltage)

Thank you for the help so far. I will let you know how it turns out.

 

The battery cables on these trucks often have corrosion underneath the insulation that you can't see until you chop them up. You may get full battery voltage when doing these tests, and still not get the necessary amperage to the starter to engage it. The small + wire going to the solinoid should be 12v only with the key held forward to start. Many of the solinoids have a second small terminal to ground the coil. You may want to use this to make sure the solinoid is getting a good ground. The best way to verify a bad ground for the entire truck, is to use jumper cables between the ground post on the battery and the engine block. Just make sure those cables aren't laying over anything that moves. If your problem disappears you found the problem.

 

The testlight is is not denoting power, it's showing current flow. There is always a small amount of current flow through most modern vehicles, depending on how many devices they have(radio memories, ECU memories, etc.) But the small current used by the electronics in the vehicle are not enough to light the testlight. So you will always get a 12v reading with your meter, it will tell you nothing because it's too sensitive.

 

I won't say this is incorrect ... However it is not exactly accurate.

Yes, Some Solenoids/Relays have a ground terminal, however they are not used as starter relays typically ...

Starter relays have 4 terminals and are base grounded.
Large Terminal to Starter
Large Terminal to Battery
Small 'S' terminal to 12v+ keystart
Small 'I' terminal Ignition resistor bypass for startup.

Connecting ground to any of those terminals is a disaster in action!

-Enjoy
fh : )_~

 

Your problem sounds a little like mine last week. I was using a battery I was pretty sure was good. It read 12v. It struggled to turn the engine over. Since it is fresh from the machince shop I assumed it was just a little tight. After a couple of days of starting the engine is finally quit working. I bought a new battery and it fires right up.

Even though the battery read 12v it just didn't have enough current (amps) to drive the starter. Take your battery and have it tested.

 

You can use one of the small ones as a ground Festus, a relay is a relay (this one is just BIG). You need a ground and +12v to engage the coil and make the two large terminals connect. It usualy can get a sufficient ground from it's base, but these trucks are old and rusty. You can put the +12v trigger from the ignition onto either of the small terminals and it won't make any difference. Just never ground the large ones of course. You could even supply +12v constant to one of the small terminals and use a negative trigger from the ignition to engage the coil. Some cars actually do this nowdays. Both of my trucks have had the 2nd small post grounded for years. My 93 bronco has about 25 relays in it (factory and mods together). Not trying to start an argument or anything, just trying to clear up some of the q's about relays and solenoids.

 

Sorry man, but you are wrong on this one. We are in a Ford forum talking about the solenoids(starting relays) that Ford(and most other OEM cars and trucks use), and that's not the way they work.

Now like the other poster said, you can get solenoids that do hook up like you said, but they are never used in a automotive situation that I have seen. I have seen them used in forklifts, manlifts, and other equipment, but the only time you might see one that uses the small terminal for ground in a automotive application would be for a snowplow or possibly a battery charge relay or something added aftermarket.

 

Franklin,

Seems you were right. I forgot that I changed both of mine out for a heavier duty aftermarket one years ago. I had issues with corrosion under the cables like many other Ford owners, so I ditched everything, and redid it from scratch. So if anyone needs a better ground to a factory coil, just run a ground wire to the mounting bolt(s). Jumper cables are still the best method I have found to prove a bad ground situation.

 

Ford uses them on Diesels for the Glow Plugs as well ...

-Enjoy
fh : )_~

 

Yep, forgot about that one.

 

It's annoying, I wish they didn't look the same ...

-Enjoy
fh : )_~

 

Fixed the issue. I stated earlier that the hot wire to the starter looked like it had grounded out at some time on the starter case, well I moved the connection on the starter to the outside of the positive tab (instead of between the plastic retainer and the positive tab). Started right up.

Thanks for all the help everyone. Couldn't have done it without ya.