Have a newly purchased 2003 XLT v6, manual transmission 2 whl drive w 79k miles, trying to register. Problem is sometimes engine does not fire. In this state, when I turn key on instruments spike up for a second and then all go to zero. At other times, I can tell as soon as I turn key on all gauges energize and stay energized, it will start. In all cases engine turns over well. Once the truck is running it doesn’t stall at least it hasn’t for me yet. But when I shut it off, at times it won’t start, yet sometimes it does. And the no start condition can last for days. Tried disconnecting the battery and reconnecting didn’t start for about 3/4 hour and then it did just before the tow truck was to arrive. Assuming I have an intermittent electrical short or wire problem somewhere but don’t know where to start. Help !

 

Additional Info: Truck has an exhaust manifold leak ( not sure which side ). May impact issue ?

 

Engine bay fuse box. Check fuse #10. Is it melted or burnt in any way? Do you have crank but no start?

 

Will check fuse # 10. Note during intermittent problem, engine turns over but does not start. Other times engine starts and runs until I shutoff key.. Since the truck starts at times normally and can run a while, could this fuse be the defective culprit ?

 

Yes, it could be. It is the easiest to check first while troubleshooting. On 2009 - 2014 f150's; it is fuse #27. They sell a relocation fuse kit. It gives a larger gauge wire pigtail and higher amperage fuse. Basically ford cheaped out put a smaller 20a mini fuse, where a thicker gauge wire and heavy duty amp fuse should have been. So overtime the fuel pump fuse slowly melts, not totally blowing out. Thats when you get the intermittent no start. Ill try to find some old pictures of my fuse.

 

 

Since yours is a 2003; try this you tube video link.

 

Another good in depth vid. Shows how to troubleshoot the fuel pump wire harness and which pins are powered up to work.

 

Ok, cannot try until Wed. ,truck is about 45 miles from my home. Thankyou