First of all I am new to this forum and new to ford trucks.


Picked up a 1986 f150 xlt two weeks ago. This truck has two problems, so far.

First is the starting problem. The truck wasn't cranking at all, so I replaced the following: starter, battery cables, starter cable, starter solenoid. The alternator looks new, previous owner said it was replaced a couple months ago. Had the battery charged and checked ; it's good. Now when I go to crank the truck it completely drains my battery. Im not talking about attempting to start it for about 10-15 minutes, it only takes one or two tries to drain the battery. Swapped my battery from my camaro and it did the samething.

What can be causing my battery to drain after one crank?


Second problem is that the fuel pump next to the drivers frame rail stays running when the key is on.




thanks in advance

 

Do the test below. Make sure the domelight is off, key is off, and if you have a hood light, unplug it. If the testlight lights, unplug each fuse to see if you can make it go out. If not, take the alternator wires off and see if it goes out.

 

Just did the test and the light
didn't come on.

Also does this wire go to the negative post? I already have it connected to the negative post, just want to make sure.

 

Anyone have anymore ideas?

 

What does the engine actually do when you try to start it? Does it turn the engine over at all? Nothing is going to be able to "drain a battery with one crank". There would be a lot of smoke if that happened.

Also try this: Turn the headlights on, and while someone is watching them, try to crank it. Do the lights stay bright, or do they go completely out when you turn the key? Do you hear any clicking noises?

 

It sounds like the engine wants to turn over but then the battery goes dead. Did this to two batteries. Doesnt actually turn the engine over.


I will get the battery charged and try the headlight test and get back to you.


Thanks

 

I agree with Franklin2, I can't see how a battery can be virtually instantaneously discharged
using a mere starter motor in a few seconds without everything self destructing, there would
be lots of smoke & heat & melted wiring & sulfuric acid everywhere. This can't happen.

Have you performed the test mentioned with the headlights? What about the clicks?

What is telling you the batteries are suddenly dead? Have you verified this with a voltmeter?

As for that wire, I'd leave it disconnected until I found out exactly what it's supposed to be
connected to. All of Ford's ground wires are black, I suspect the loose end in that picture
has got another loose end somewhere as a mate.

 

The battery was at 12.60 before i cranked it. After it went down to 3.5 and slowly began to climb up. I was using a multimeter

 

Are you putting your meter leads directly on the battery or on the terminals? If you have a side terminal battery, you probably can't get directly to the battery terminals. Anyway, you might have a poor connection at the battery that would cause that voltage drop.

I just re-read your first post and see that you have all new battery cables, so it's probably not a bad connection. Are you sure they are hooked up correctly?

 

Did the headlight test and the lights dim when cranking the car.

The battery cables are on nice and tight.

Solenoid conections are good aswell.


where does this ground go connected to?

 

I would pull the starter back off and test it on the ground with some jumper cables to make sure it works. If it works ok, I would make sure the mounting surface where the starter mounts is clean before you re-mount it.

 

how do i test the starter with jumper cables?

The starter mounting surface was dirty because it looks like it has a leak at the oil pan.

 

It connects to the hood and ensures a positive ground to it so it (the hood)
can be used as a ground plane by the radio.

 

thanks.

Anyone have a wiring diagram for the engine bay?

 

Sounds like you have a open circuit or drain. Check the fuse box and make sure there hasnt been any P.O.'s bad wiring. IE: they ran a cable from like a kill switch/radio amp/radar/etc and the other side of the wire in the fuse panel is "bridging" the fuse and it stays open(aka constant power)
Test by hooking everything up (ignition off) and seeing if you can find a 12v draw on the dead side of the fuse. (pull the fuse out to test)

Also check your neutral safety switch, a bad one can also cause a overnight drain. (d.s. tranny)