I am stumped!

1999 F150 stepside, 150k, 5.4L. It's my daughters truck.

Been having a problems recently not starting, then finally quit.

History:

1. All maintenance up to date, including a new fuel filter.
2. Replaced fuel pump relay and PCM relay. Checked all related fuses with VOM, all good. Checked PCM diode and got about 0.5 ohms one way, infinity the other. This should mean it's fine.
3. Checked fuel pressure; none.
4. Pulled off bed, and pulled pump. Hot wired, and pump ran fine.
5. Ignition on, pump runs for about a second, then stops (normal).
6. While cranking, pump does NOT run.
7. Jumpered around fuel pump relay, pump runs fine, 40 psig fuel pressure. Doesn't hold pressure that well after releasing jumper, but still takes a minute or so to drop to 5 psig, so I'm not suspecting the regulator.
8. Using spark tester, randomly checked some of the plug coils. All worked fine, so it would seem the crankshaft position sensor is working fine.
9. With jumper around fuel pump relay, pump running, 40 psig pressure, truck still won't start.
10 Jumpered around PCM diode, still won't start.
11. Started checking injectors with noid light: nothing. WTF?!

Before you ask, no there's not a PATS problem (light goes off after a few seconds, and does not blink). I've tried both keys and everything seems fine.

Also, the CEL has not come on, and when I attached an OBDii analyzer from Harbor Freight, no codes come up.

So I have a triple mystery:

A. Why is the fuel pump not running when the engine is being cranked, when clearly the wiring is fine, all relays and fuses work, and the fuel pump works?
B. Why are the injectors not pulsing?
C. Why no CEL or codes?

The only thing that seems to be a common thread is the PCM. I have no problem replacing it, but only if it's truly bad. How can I check? Or am I just missing something? Could it be the cam position sensor?

Help?

 

does the 99 have some type of "inertia trip switch" on the passenger side kick panel that is suppose to trip out the fuel on front end impact ?

 

FORD INERTIA SWITCH FUEL PUMP SHUT OFF F-150 MUSTANG TAURUS RANGER EXPLORER | eBay

 

Well, yeah. But it's inline with the power circuit to the pump. If it was not working correctly, the pump wouldn't run when I bypassed the relay. And, that was the first thing I checked. It's not tripped. Hence, the mystery.

 

A,B,and C depend on the PCM having power and the crank sensor feeding pulses to the PCM during cranking.
If not, nothing works. No injection , no fuel pump, no Ignition.
None of these can cause a CEL to light as a fault indicator.
CEL indications and codes are driven from a running PCM program only.
If the PCM is not running it cannot set code or the CEL lamp.
Good luck.

 

Locally I know a shop owner who has the ability to check Ford specific on board computers.

You might want to find someone with the right equipment to check your PCM before you buy a replacement unit.

 

I had a similar issue, but it would start after a long delay.
Replaced regulator, crank sensor, cam sensor, fuel pump. Finally brought it to a mechanic.
Using a noid light, found that injector signal was delayed, traced it back to PCM.
Replaced the PCM and all is fine.
Not saying that it is your problem, but it is looking that way.

 

Bluegrass 7, notice in step 8 I tested firing with spark testers, and it works fine. Therefore, the CPK MUST be working, and the PCM MUST be getting power. It doesn't mean the PCM is working correctly, and hence the mystery.