I have a '99 f250 w/5.4v8
About a month and a half ago the truck suddenly wouldn't start. It would turn over just fine, but wouldn't fire. We would eventually run the battery down but once we jumped it, it would start right up. We then discovered that when it wouldn't start, even though the engine would crank normally, as soon as we jumped it from another vehicle it would fire right up.

I took it to a ford dealer, and the tech (puzzled) finally decided it was an intermtent battery problem. The battery supposedly had a dead cell that didn't always show up when tested. He said even though the engine was cranking over just fine, there wasn't enough electricity left over to fire the engine. This sounded illogical to me, but what do I know? So we put in a brand new battery and that seemed to solve the problem... until now. It did it to me again this AM. So we immediately put the jumper cables on it and it started right up.

So my question is: Why would the engine crank over at normal speed, (the battery apparently fully charged), but not start until you put jumper cables on it from another vehicle???? It's an interrmitent problem, it might start again the next few times, but will eventually do it again.

Given the symptoms, seems like there would be an obvious answer (just not to me, or evidently the tech).

Anyone????

Thanks
Figgy

 

sounds like battery problem to me. you need at least 12 volts when that thing is cranking.if it drops down that it wont kick her over. so have a friend crank while you check battery with a voltmeter.double check all your connections and clean your battery terminals.

 

It clearly seem that the 'Electronincs' are not gettng high enough voltage due to the drain the starter is taking.
Could be the starter.
Could be the cables and connections.
Could be fuse seating or ECM relay dropping out from the low voltage.
Voltmeter testing should find this condition.
What often happens is the tech tries to fix it in reverse by making the problem fit the fix. You only do that after the fault has been found or it is chased until lightening luck strikes.
Good luck.

 

A) Take it back to the dealer that 'fixed' it and make them FIX it. You've already paid them, so this trip will be free.

B) Tell them to check power & ground at the PCM & coils during cranking.

 

Thanks for the replies.

I think I will show your replies to the next tech, maybe it will help.

figgy

 

I wonder if this is my problem? I have the optima yellow top, its been in there for about 4-5 years, it will crank over just fine, but sometimes it wont hit for a long time. I dont see how thats a battery problem though