86 F250 driving me nuts. Been jumping the solenoid to start it. Key won't turn the motor. Recently when doing so the starter has been staying on. Obviously making a horiffic noise being spun by the flywheel. Had to actually disconnect the starter cable from the solenoid to get it to disengage from the flywheel. Something is draining my battery as well. Replaced the starter tonight. Nothing. Battery is dead again. Going around in circles. ugh. Please help. Need the truck for work. It's killing me.

 

First thing how old is battery? Just a couple few near complete discharges and it will be toast. If it's not too old say less than three years, get it on a charger ASAP, it would be difficult to overcharge it at this point, at least for a while.

Clean it thoroughly and the battery posts with a wire brush. If it needs replacing, replace it. Cables and ground straps and solenoid etc are now 30 years old, grounding surfaces get corrosion and galvanic action between them and the engine block, ground points, frame, firewall. Very common problem. These need replaced. If you have a parasitic load, disconnect the negative each night and at work, till you find the problem.

While the battery is charging go over all of the ground and connections themselves - break each bolt free, each connection, every inaccessible frame to block and block to firewall connection and grind down to BRIGHT shiny metal and tighten securely. Coat with NO-OX or vaseline, etc.

Find a NOS Motorcraft solenoid and pair it with your new starter. Do NOT use the $4.95 solenoid specials. These solenoids ground to the firewall through the bracket. This needs solid ground too. If the voltage/current feeding the big solenoid lugs isn't where it needs to be they can stick, and probably el-cheapos are more prone to this too. Good ones are noticeably heavier than the junk, made with more good stuff.

So anyway, 12.8 volts is what you want to see from a good battery - replace those 30 year old ground and starter cables - install a _good_ solenoid - and it will be ZIPPING that starter right along, cold or hot. Trust Me. Let us know what you find. Do it right, do it once.

 

Ignition switch ?

 

That too. Probably roasted by now.

 

Fully charge the battery.

Remove all the wires attached to the fender relay except the starter and battery + cable.
Be sure to close the truck doors so you are not using the interior light.
Take your test light and connect it to the battery + stud, then touch each of the removed wires (one at a time)
What color is the wire that makes the bulb light up brightest?

Connect a test light to the little red/blue wire on the 'S' terminal of the fender mounted starter relay.
Check to see that it lights up when you turn the key to 'Start'.

 

A couple years ago I changed the ignition switch. Mechanically stopped working. Worn out. Last summer I changed the battery cables, neutral safety switch and the ground going down to the frame. was fine for a while. A few months ago I noticed the back up lights stopped working again. a month later the key stopped working. I changed the solenoid. Nothing changed. Been jumping the solenoid for a while. Then the starter started sticking on. what a mess. changed the starter last night. battery dead. charging it now. but seems like it must be a ground issue?

 

Not sure what is killing your battery until you do some basic troubleshooting.

Backup lights not working might point to the NSS being out of adjustment or failed.
Have you tried starting in neutral or while moving the gear selector?

 

I would do as ArdWrknTrk posted so you know that all the connections are good and if there is a drain on the system.


I would also check the IGN switch if in adjustment and do the same with the NSS.


When you say you jump the SOL to start it how are you doing this? Power from + side of batt to the small lug marked "S" or from + to the large starter cable?
Dave ----

 

thanks...I only have a digital tester. I will buy a small light tester and try those steps and report back.

 

oh and the battery is only a year old. also still no back up lights but we'll get there eventually.

 

Yes I understand what you're saying but keep in mind auto start batteries have a bunch of thin plates inside, the design providing lots of CCA but they don't like deep discharges. Age really doesn't factor at all in this situation if the battery keeps getting lunched like that. It will fail in a couple days from brand new, if it keeps getting drained all the way.

Running this type of battery dead (as opposed to HD marine "deep cycle" batts designed for this) just a few times maybe a half dozen, may well kill it. Add in the parasitic drain you mentioned and it's guaranteed to at least cripple it severely. This causes it to sulfate inside and lose capacity.

Here's the really fun part. You ready for this? Now that the battery is wacked, this in turn can eventually roast the alternator and/or voltage regulator! Finally, the lack of voltage regulation aren't doing all those sensitive chips and printed circuits any good and all the rest of it. This gets important too when injectors enter the mix. Nice huh?

One big misconception out there is the notion that, if the engine starts, the battery and charging system is all charged up and A-OK.

Not trying to beat up on you, just trying to save you some coin.

 

I suggested a test light because you get visual indication that you can see from inside the cab.

Plus you can tell by how bright the lamp is.

 

thank you again! Reporting back asap.