So I go out one morning and the truck would not crank. When I turned the key I heard a relay click from under the dash and a relay click from the engine compartment. It was a single click, not the repeated click that usually points to a dead battery. I tried to start it later that day and after about 10 tries of it just clicking once it started. I took it to Advanced Auto and they ran the starter system check and said the starter and alternator where fine but the battery was going bad. I put a new battery in and it started up fine. Just to be cautious in case the battery had been sitting a while, I drove the truck for a good hour to make sure the battery was fully charged. The rest of the day everything worked fine, when the key was turned it had a very strong crank and started immediately. Well the next morning, nothing, back to the single click. I usually keep trying to start it and it will eventually work and start up fine. Also, jumping it sometimes helps, it will work after the 5th try with jumper cables, maybe the 30-50th without. I had the new battery checked out by Advanced Auto and it checked out fine. Once I get it started once its fine for the whole day, it's only the morning that it has the problems. When I short the starter relay it does not start in the morning but when I short it when it would normally start after it has been running a little that day it starts fine. Everything points to a problem with the battery but It has a brand new deep cycle battery that has been fully charged that has tested with upwards of 800 CCA. Does it seem like a battery problem or more likely another part of the starter system? I feel it could be something slowly draining the battery, could this be it? If so, how would I go about locating whatever is draining the battery?

 

what are we working on here?
if it cranks after a bunch of times then the battery is charged most likely. check the cables and connections.

 

Sorry forgot that, its a 2001 F150 5.4L. Also, when I get into very high RPM's about 4500-5000 the dash lights and headlights start dimming and the battery light flashes. Could this be related? I have a edge and it shows a battery voltage of about 12.5-13 when it starts, about 11.8-12 when it doesn't start, and 13.9-14.6 when running. When I turn the key and it doesn't start the battery voltage drops to about 11.0 from 11.8 and drops as low as 10 from 12.5 when it does start. Just more detials I'm remembering after the post.

Matt - I attempted to check the connections visually and shake them a little bit and they all seemed fine, I will try a much more thorough check though tomorrow, Thanks.

 

the dimming and the flashing battery light sounds like a charging issue. but the voltages seem normal for running and while shut off.