Hi Guys and Gals,

I recently purchased a 1997 F150 4.2 Liter. On the way home it started missing. Within the next few days it died on the side of the road. After towing home I found no spark. A few days later I t started but only for a few minuites and died. No spark, coil pack is new so I replaced the CKP and it started up. Drove it about 1/2 Mile and died again, No spark again. Not getting power to coil pack when I am turning it over. So in short, new coil pack and CKP sensor and no spark. If it sits for a few days it may start or it may not. But if it does it only runs for a short period and then no spark again. Any help sure would be appreciated.

Best

 

Well, you do know the coil pak has to have 12 volts suppled through a fuse so the PCM can apply a ground to fire the coils.
Have you checked out the fuse location for a faulty fuse and seating and test measure for voltage to the coil pak?
Maybe it's a harness issue.
Since it is intermittant, it's a loose contact/connection at some point.
Good luck.

 

Might want to swap out the camshaft position sensor. Had an issue like this with a 6.8 and that was the fix since the computer compares both the crank and camshaft sensor signals prior to providing what is required to produce a spark at the coils.

 

Fuse 30 is a 30 amp and feeds power directly to the coil pack. it is in the junction box with the relays and the power diode. Check that it not only is good but the area it plugs into isn't damaged. A good flash light and some needle nose pliers can fix it. If you have power to the coil, than your next question is is the relay good to the PCM. Fuse 24 in the power distribution box powers the PCM relay.