Thanks for reading . My 2003 expedition has a 1year old battery, alternator is 6 months old. I checked voltage of battery is 12.4 when truck is on the voltage jumps to over 13.4. But when I go to start truck i t doesn' start unless my jumper is connected . What could this be ?? Where' does the ground go too?? Can' see end, also could it be the starter failing I've never replaced it and it has 206000 miles. My f350 failed after 180,000 miles. Is there a regulator that' failing any help would be great.
matt

 

Are the battery terminals clean and in good shape ? Is it a Group 65 battery ? Not a AutoZone Duralast POS is it ?


-Mike

 

I replaced the terminals, it's a interstate 65 battery. Can anybody that is experienced with repair have any ideas what's going on.
Matt

 

Cranks/Turns over = spins but not start
Start = engine fires off

We need to know which terminology you are using to describe your problem. Is it clicking but not turning over, or is it turning over but not starting?

Your negative battery cable goes down to the engine block and the frame.

 

The alternator output is low. You need at least 13.8v to charge the battery.

 

I thought the normal maximum charging voltage should not exceed 13.8v for long periods and 14.4v for periods up to 8 hrs.
Also, any voltage higher that 12.4v will charge the battery, but 13.8v is optimum.
Our 2003 Exped works exactly like this - 14.4v right after starting and drops to 13.7-13.9v after 20 min or so.
Our 2002 Excur goes to 13.6v after starting and drops to 13.2v.
I've checked this using several voltmeters because the lower voltages on the Excur seemed odd.
Both have been working fine with no battery issues for several years.
http://www.operatingtech.com/lib/pdf...20Charging.pdf

 

Because the battery is charged so the voltage backs off. If however the voltage never got above 13.4v to charge the battery it will eventually get weaker and weaker. It'll happen even faster with accessories and headlamps turned on.