Diagnosis please..

[03trubluGT]

I've been driving the 1997 F150 that I've been working on for my son.

Yesterday I went to pick him up from school in it and when he got in the truck, it didn't start, just one click.

I had the wife pick us up and I came back with a hammer and a few tools as I thought the starter (reused from the old motor) had just frozen up (like starters do). I gave it a couple of whacks, but again it just clicked.

I decided to jump it (for the hell of it) and it started right up.

So now I'm confused on what the issue is. It has a brand new AC/Delco battery with 675 CCA, but the starter and alternator are the old ones from the other motor. I have put almost 1,000 miles on it since the motor swap.

When I got home I disconnected the battery from the running motor to see if the alternator wasn't doing its job, but the motor kept running. I turned on the lights (high beams) and the motor kinda stumbled, but kept right on running. I then turned the AC on MAX and it kept running, so I'm guessing the alternator is doing it's job.

Could it be the starter just getting old (mind you I don't know if this is the oringinal starter, or a replacement)?

TIA.

[Lason]

Check and clean the battery terminals and also the end of the battery terminal that bolts to the block. Sounds like a loose ground somewhere.

**EDIT**
Just to elaborate, when I ground the battery to the vehicle I will run the negative battery cable straight to the block and another cable from that point to the frame. And always use a wire wheel on the frame and block where your bolting the cables too. I have had too many odd things happen because of bad grounds.

[habs4me]

I've been driving the 1997 F150 that I've been working on for my son.


When I got home I disconnected the battery from the running motor to see if the alternator wasn't doing its job, but the motor kept running. I turned on the lights (high beams) and the motor kinda stumbled, but kept right on running. I then turned the AC on MAX and it kept running, so I'm guessing the alternator is doing it's job.



TIA.

I've heard that's a good way to fry the voltage regulator

[03trubluGT]

Check and clean the battery terminals and also the end of the battery terminal that bolts to the block. Sounds like a loose ground somewhere.

**EDIT**
Just to elaborate, when I ground the battery to the vehicle I will run the negative battery cable straight to the block and another cable from that point to the frame. And always use a wire wheel on the frame and block where your bolting the cables too. I have had too many odd things happen because of bad grounds.

I'll check the grounds today before running to the parts store.

I've heard that's a good way to fry the voltage regulator

Ewww.. The voltage regulator is inside the alternator these days, correct?

[BP]

When I got home I disconnected the battery from the running motor to see if the alternator wasn't doing its job, but the motor kept running. I turned on the lights (high beams) and the motor kinda stumbled, but kept right on running.
TIA.

Don't ever do this, it can send a voltage spike through everything. If it's idling with the AC on max, high beams on, radio and while rolling the windows up or down then the alternator is working fine.

When you go to start it turn on the headlamps and have someone watch them. If they go completely out when cranking then you have an intermittent connection somewhere, possibly due to heavy corrosion. If they dim considerably then there is excessive current draw somewhere, possibly either heavily corroded wiring or inside of the starter. If they don't do anything then look at the starter solenoid or ignition switch.

[SC457A]

Have the battery checked also... I have seen new batteries lose a cell.

Sounds like a ground or battery issue to me. The fact it jumped off makes me question the battery.

[~Necromonger~]

x2 on a loose ground. Also if you have a loose ground it will not let the alt. charge the battery! Then you have a low battery on top of a bad ground wich can leave you guessing. Put the battery on a charger chase down the ground wire check connections (tighten every thing)and you should be good.

[94mstng94]

I've put a positive battery cable on a few ford trucks due to excessive voltage drop.

I would replace the cables.

[03trubluGT]

I'm gonna crawl under it this week and see if I can locate any loose ends.

[mustgofaster]

I'd expect to find a bad batt cable or terminal, or a bad ground.

[91CoupeMike]

I've heard that's a good way to fry the voltage regulator

And ECMs.

[JimD]

I'm gonna crawl under it this week and see if I can locate any loose ends.

Engine block ground is on the drivers side front corner. I'd be load checking that battery.

[Baba Ganoush]

I've put a positive battery cable on a few ford trucks due to excessive voltage drop.

I would replace the cables.

Yeah I would replace both cables, or strip back the ends til I didn't see any corrosion and replace the terminals. I had the same symptoms and it turned out to be the terminals and corroded cable.

[line-em-up]

Check and clean the battery terminals and also the end of the battery terminal that bolts to the block. Sounds like a loose ground somewhere.

**EDIT**
Just to elaborate, when I ground the battery to the vehicle I will run the negative battery cable straight to the block and another cable from that point to the frame. And always use a wire wheel on the frame and block where your bolting the cables too. I have had too many odd things happen because of bad grounds.

x2

A voltmeter comes in handy and is a simple way to see where the voltage is dropping.