My 99 F250, 5.4 has a strange problem. Occasionally, it just won't start. It has a brand new battery in it, and it cranks over just fine. But it just won't start. Until you put a set of jumper cables on it from another car and it will fire right off. What would cause this?? Seems like the symptoms would really narrow the possiblities.

Thanks
Figgy

 

#1-You may have gotten a bum battery it's been known to happen.
#2- Grounding fault, when you hook up the cables you may be completing the ground.

My .02.
Hope it helps!!!!

 

Have you had your alternator checked? Sounds like you are running off your battery or you have a open circuit that is draining your battery when the engine is off. Do you have factory antitheft or after market alarm?

 

If the engine cranks properly, there's nothing wrong with the battery or the primary battery cables.

You will need to see which of the three requirements for engine operation is missing: Air, Fuel, and Spark (all at the correct timing, of course).

Steve

 

Thanks for the replies.

Yes, the engine has always cranked over just fine. The battery is not dead (unless I crank on it so long as to run it down).

That's the funny thing about this. Engine cranks over just fine but won't fire. Hook up another vehicle to it with jumper cables, and it fires right off!!

That's what I mean, it's so weird that I would think the possibilities would be limited.

Thanks again

 

Well, is there any chance that something is getting moved during the jump process?

Do you have any additional wires coming off the battery terminals that are pinched when you attach the jumper cables?

When it doesn't start is the hood in the same position? Perhaps a hose is pinched when the hood closes.

Right after the truck starts, turn it off, disconnect the jumper and see if it starts.

Turn the truck to on (not running) attach the jumper cable and just listen. Perhaps you can hear the fuel pump start. Does the engine on the other vehicle slow when the cables are attached.

jeff

 

Hey, I'm am having the same problem in my 2005 f150 fx4. I get another vehicle and boost it and it starts right away. Had it in at the dealership 4 time and a private mechanic 1 and they still don't know what it is. I was wondering if you found out what is was?

 

throw a voltmeter on that battery and have a friend try to start her see what u get. should be getting around 14 volts when she idling.if all that checks out ok them its on to fuel,air etc..

 

Actually I think we did figure it out but I'm not sure I understand it.

It was the fuel pump I ended up having to have it towed the last time because it would not start at all this time. It did act like it was out of gas but I knew it wasn't. All I know is that ever since I had the fuel pump replaced it's worked fine.

Could fuel pump have been weak and it would only work when it had additional juice to power it??? I don't know. If this makes sense to someome, feel free to 'splain it to me.

 

Thanks for the tip, I'll see what the dealership says. The truck died on me the past 2 mornings, and then again tonight so ford picked it up and it's there problem now. I told them i didn't want it back unless it was fixed! I tried starting it with another battery too, same thing didn't go. So hopefully they find out this time (5 trips later)

 

Finally got the truck fixed. It turns out that it was a defective starter and circut, they replaced it and it fires up faster than you can turn the key. It's about time they got it! Thanks for your help though guys.