Hey all, im having some trouble with my '01 Ranger with the 4.0. A little backstory, I was going to leave school the other day and my truck was pretty much completely dead. power locks barely worked, chime worked but when i went to turn it over just clicked and died. Ended up trying to jump it with a friend's truck and nothing. battery just got weaker and weaker. then I tried replacing the battery with a brand new one and it worked perfectly. Now, 2 weeks later, I go to start it this morning and the same thing. the battery was super weak. tried jumping with a jump pack, my suburban, same thing just got weaker and weaker. battery terminals were all clean and tight, now i go to start it and nothing happens, but if I leave it in the on position the theft light flashes rapidly and something in my intake clicks along with the light flashing. voltage gauge also reads low. any ideas? I'm suspecting that i have a bad ground somewhere but I ran out of time to mess around with it for today.

 

Welcome to the forum

Need exact voltages
A new battery will be 12.8volts
3 year old battery 12.5volts
5/6 year old battery 12.3volts and time to shop for battery sales
12.2volts or less can be no start
Under 12volts IS a No Start

You may have a Key Off battery drain, or failing alternator, so new battery voltage was slowly drained after a few weeks

Car batteries are only made to Start the engine, after start up battery is off line, alternator powers ALL the systems
After start up battery volts should be minimum 13.5volts to maximum 14.8volts, that's from the alternator, so voltage flows TO the battery after startup to keep it charged up
Once you get engine started test for that with volt meter

The new battery may have been ruined if drained under 12volts so see if you can replace it under warranty
If battery is under 12volts then Jump Starting may not work, the "other" battery's voltage is just going to the Low voltage battery, so nothing left for vehicle's system, i.e. starter motor and PATS

Rapid Flashing Anti-theft light can be from low voltage in the system, so thats "normal", but for sure prevents starting
And if you try to start engine 3 or 4 times and get that rapid flashing Anti-theft light each time, then computer will go into LOCK DOWN mode, you have to wait 90min before trying to start again, its an anti-theft deterent

So first thing to do is to test battery voltage, needs to be higher than 12.3volts, for sure, recharge it if not, or see if battery place you got it from will replace it

Once you get the engine started test alternator voltage, at battery, if under 13.5volts then fuse is blown or alternator is bad
If alternator checks out OK then you will need to use an AMP meter to see if vehicle is draining the battery when key is OFF, something is on when it should be off

 

Thanks for the info, i took the new battery in to get tested and it failed so I got a new battery under warranty and tested the alternator and it failed. Replaced the battery under warranty, installed the new alternator, and put in a new negative terminal cause mine was about to break and it runs great now. Thanks!

 

Good work

Thanks for update and THE FIX, it will help someone else down the road

 

IMHO... It doesn't hurt to do a complete overhaul of the Grounding System in the Engine Bay and add a couple of extra ground wires.

Add an additional fine stranded ground cable from the Alternator Mounting and the Starter Mounting Bolts to the main ground either at the frame or the battery. These two wires alone help the components get a full flow of current and not go through the tiny braided engine ground strap or corroded attachment points. Also replace the engine to frame and the battery to frame cable with good high quality fine stranded cabling.

A PITA for sure but it will help the overall Charging System keep things working properly and may even extend the life of other components.
I have seen a How-To on the subject I believe on this site.

Good to see you have it fixed but now for the prevention !