Greetings to all,
I've got a '01 F250 7.3 PSD that has been cranking slow lately. I took it to Advance Auto Parts and they checked both batteries. Both were good, one was weak in need of a charge. Charged it (battery charger). They also charge in the truck, putting 13 plus volts as it runs. When it starts it feels as though only one battery is cranking it. Battery post and cables are clean. Any suggestions? Cables bad? Alternator ?

BTW it not a cold weather start issue...I live in Miami FL.

 

Check voltage at the battery while cranking should be >10.5vdc even if only 1 is bad its better to replace as a set or the older one will bring the new one down to its level.

Check voltage at 2K rpms should be ~14.5vdc

 

I believe the generally thought around here is always replace both. You need to unhook the batteries to check them. Make sure you replace with a good heavy duty battery. Check you cables, it is possible one is bad, not likely. Keep us posted as to what you find. Oh Yea, Welcome to the Boards.

 

Trust me from recent pain with the batteries, change them both...

https://www.ford-trucks.com/forums/5...-no-go-go.html

thanks
-mike

 

well if you have way to check it with a set of batteries , and make sure it will spinn fast than yuo just get batteries, if after you put 2 new ones still cranks slow, it moght be your starter, i had similar problem , it was my sterter,

welcome to FTE

 

You must load test each battery out of the truck, if not it will pull from the other and give a false reading. If you replace one, it will drag the new one down to the older one's rating and specs as they are hooked together. A bad starter or poor connections/cables will also present weak battery symptoms. Hence the out of vehicle battery tests.

 

My truck was doing the same thing. I went to Sams and bought two Optima
batteries, red top, Their expensive but they sure turn the engine over good.









2002 PSD 4" exhaust, AIS, Super Chip.

 

Thanks for the advice...as you mentioned I did have to take them out to load test. Although they showed good at the Advance Auto parts portable tester it gave a false reading. I took them out and had them load tested and alas, one bad battery. Needless to say both got replaced.

Note; to all others if you are having the same problem don't check the batteries while installed in the truck, remove them...test them individually prior to proceeding. Wish I had done that prior to removing alternator, starter, cables, etc....

 

A special thanks to all that replied with you kind words and advice...cheers

 

Glad to hear you got her fixed. And glad to have you here as a member. Hang around and we'll help you keep your truck running good and if you let us, we'll help you spend you're money.(it's a go fast, make smoke thing)