2002 f150. Love my truck. Got it new with 30 miles on the odometer. It’s been a great truck. Only thing I haven’t done myself having transmission rebuilt at around 250,000 or so. Recently...started by changing water pump and fan clutch assy. While in that,my attention was drawn to throttle body. Decided to clean it.
During that process one of three PCV connections (not 1 going behind IAC) was blocked completely. Replaced entire t. body assy. with one pulled from salvage yard. Long story short, after T.b. swap I got a crank no start for several days with no real indication of why it finally began starting. A month or so later, I got an idea about where a pain in my butt coolant leak that mainly showed by not holding a vacuum on coolant system. That being the intake manifold plenum on the coolant passage. Back to the salvage yard for an intake manifold. Replaced it, all COP’s, spark plugs, gaskets etc. That was 4-5 weeks ago and ever since it’s Crank/no start. I’ve done lots of testing, bought many tools. This is what I know-no spark at all, only 1 initial pulse on f. injectors (all 8) when cranking. Fuel pump works. Replaced CKP with no change. I feel like it’s an electrical issue in the CKP circuit. Can anyone tell me what voltage should be produced at harness connector. Also,CKP sensor wires (2) on my sensor, are shielded). How does this impact typical circuit tests?

 

PCM relay? What codes?

 

Codes gone due to disconnecting (-) battery cable for extended period of time and battery recharging.

PCM relay bench tests fine. Relay “socket “ at PDB tests as follows...pin 30-hot. Pin 87-grd. Pin 85-grd. Pin 86-nothing. This was KOEO.

 

Bench testing the relay may not pinpoint an intermittent relay.

Just swap the PCM relay with another identical., non-critical relay to test. Mark them first.

 

When my 02 had an intermittent crank/no start problem, I got the code that is triggered when the codes are deleted, the battery is disconnected, or power is lost to the PCM. I had not deleted codes nor disconnected the battery so I replaced the PCM relay and haven't had the problem since then. The relay was only about $8.

 

I have tried swapping, however I only have 1 identical relay in use, the fuel pump relay. I’ve been told swapping these 2 won’t necessarily be a good test as they work together. I’ve got 3 that are identical to those that came out of an Explorer, don’t know what their status is other than all pass bench test and all work as far as priming fuel pump.

 

Today I removed the ignition module and tested for continuity between the appropriate pins with the module in the appropriate position. Moved power dist. box as much as I could to inspect wiring. Noticed the part of the wiring harness that connects to the ABS control would drip water out of harness when manipulated. I removed the tape and ribbed cover from that portion of the harness and it had quite a bit of moisture inside. I suppose it must have been coolant that got in there when draining or refilling previously. Letting it dry out. Also will buy a few new relays.

 

Got truck running last night. Ran across this post recently and thought I’d give it a shot last night as it was quick and easy. Damned if it didn’t fire right up! SMH!