This has me scratching my head so here goes, sometimes when I go to start my 2001 F150 5.4L it will crank and no start. The "Theft" light does what it is suppose to do, comes on for about 3 seconds and goes off and there are no CEL codes. I can reset the the ECM by removing the negative battery wire and let it set for about 15 minutes, reconnect the battery wire and the truck will start and run just fine. At first I was thinking it was a fuel pump issue, however after resetting the ECM the truck runs fine until it happens again. This has happened about 3 times in the last month.

So, if anyone has any ideas what could be causing this I welcome the suggestions. Thanks

 

Might be the PCM relay. Does odometer readout show dashes ?

 

The odometer reads just as it should.

 

You still need fuel, spark and compression to start an engine. Two of those three seem to be okay.

The battery disconnect gymnastics could be merely coincidental here, so let’s actually rule out any fuel issues by slapping a fuel pressure gauge on the Schrader valve and checking KOEO and eventually KOER fuel pressures. At least with KOEO (key on engine off), you can check for fuel pressure bleeding off from the regulator.

 

Thanks for the info, I swapped out the PCM relay for a known good relay and the truck fired right up. I guess after 22 years the relay needed to be replaced.

I bought 2 relays and replaced the PCM and the Fuel Pump Relay, they both looked like they were original parts because they had Ford stamped on the relay.