I have been having problems lately with my 7.3 2001 f-250. after it was sitting for 2 days I went out ant tried to start in but when I turned on the truck to wait for the glow plug light to go off I herd a electric motor running so I popped the hood and what seemed to be a vacuumed pump on the passenger side right in back of the battery was running. So I got back into the truck and tried starting it but it just cranked and cranked and did not start....when the truck was cranking over I could hear clicking coming from the flasher relays under the dash.....I thought it was a crank sensor so I replaced that and still did the same thing...only other thing I could think of would be the glow plug relays?

Anyone have any idea or has ever experienced this problem?

Thanks,
Rednek87

 

Batteries, how old and what is their voltage while cranking. It is possible to have just enough juice to crank, but not fire the injectors with the glow plugs goin' too.

Adrianspeeder

 

As stated it takes alot of Juice to run the starter, glowplugs, injectors, IDM, and PCM while cranking. Weak batteries will cause the truck to turn over, just not quite as fast. I could hear it with my old set when winter set in. If the batteries are even close to the 5yr mark replace them. You need a minimum of an 780CCA battery as those were the smaller of the 2 batteries offered factory. I would suggest finding 850CCA or better. Motorcraft has an 850CCA battery available, which is what I ended up going with. Also keep in mind that when you replace a battery you must do both. If one is still weak it will kill the new battery in short order.

 

I replaced the batteries yesterday and it cranked over just fine....i found some 875cca duralast gold top batteries that did the trick

Thanks for everyones help!
Rednek87