Hi;
I'm trying to get my wife's 2000 F150 XLT supercab 4x4 running. It's been sitting for a while. It's not getting fuel. Pump seems OK, filter is not clogged, lines seem clear. With pump disconnected, get approximately 6.5 volts on fuel pump line. Getting the pump out was a major pain, so I'm going to replace it anyway, since it has almost 240000 km on it, and I put a new filter in, but I'm confused as to why the voltage is so low. Also, I expected the power to last for two seconds and then disappear, but it stayed as long as the key was on. Cranking the engine produced the same results. I tested the pump out of the tank with a direct connection to a spare battery; it ran and spat gas several feet, so I don't think it's dead. Does anyone have an explanation for the power situation?

Thanks

 

So with no fuel pressure and after you've verified the PCM is online, the next diagnostic step is to check for voltage at the inertia switch after turning the key on. The circuit should be intact with the fuel pump plugged in. If you can't plug in the FP, then use a test lamp with an incandescent bulb to check for voltage because the circuit needs to have a resistance to ground or you'll end up with weird info like 6v that only confuses you.

 

Thanks; I will test again with the pump connected as soon as I can.

 

Hi;
So, I've done some more testing, and repeated some I did before to make sure I didn't miss anything. I did find I got different results with the pump in the circuit. So, I checked the inertia switch again, then pulled the Fuel Pump relay. I found the relay has the 12 volt power supply present. When I inserted a jumper between pin 87 and pin 30, the pump ran. So I tested pins 85 and 86, the two coil pins. 85 has 12 volts when the key is on. No voltage on pin 86, but I think that also goes back to the PCM. Perhaps someone can confirm the PCM pulls that pin to ground to power the fuel pump? My last test was to have someone turn the key on while I was right next to the pump. This time the pump ran for a second. Cranking the engine however did not produce any pump reaction. Now I'm wondering if I should be suspecting the crank sensor; is there a way to test that?

Thanks

 

Okay, so more reading indicated I won't get spark if my crank sensor isn't working. I recently sprayed some starting fluid in the throttle body then cranked it and it fired and ran for a few seconds, so I'm getting spark. So it looks to me like I need to look at the PCM. Not sure if there's much I can do to test it. Any advice?

Thanks.

 

If you have an old cluster with analog ODO, the CEL turns off while cranking AND the crank sensor signal is present. Digital ODO cluster is useless here. W/digital ODO, check to see if the PCM is pulsing ground to the injectors or coils. I like using a test light because you can set it up so that you can see the light flash from the driver's seat. Since it busted off with starting fluid, you did have a crank signal at that time.
Crank sensors don't fail unless they've been damaged and that should be evident. The only other thing that happens to them is "terminal fretting" (TL;DR to explain, look it up) which can be fixed by just touching the CKP sensor connector. The disturbance will smush the terminal frets and contact will be restored.

I would proceed by 1) verifying there isn't an intermittent EEC power relay problem by ensuring that the injectors and coils have power w/key on *while it won't start* once that's locked down

 

2) ensure the PCM is switching ground to the injectors and coils by using a test light or noid light.
3) measure fuel pressure. If you've got enough of it
4) pull a spark plug and take a fuel sample

 

OK; you've given me some things to think about and tests to try; thank you. It will probably be a few days before I get back; work gets in the way.

 

Key on/cranking operation:
Key on powers the PCM.
That begins a timer to run the fuel pump a few seconds by grounding the pump relay until the timer times out.
Upon cranking, the crank signals the PCM, the PCM re-operates the fuel pump full time and should pressurize the fuel rails to about 35 psi. This is to allow quick starting without excess cranking.
Put a gauge on the test port to see what you have.
Pressure should have built to about 35 psi and hold for at least 10 minutes.
If this does not happen, the regulator may be faulty or the check valve in the pump is not holding or the pump is NG..
The fact that the motor will run with fuel sprayed it tells you it's the fuel system alone, at that point.
Leave everything else alone until you see proper fuel system operation..
Note; The system is designed this way to stop the pump by the crash sensor tripling open in an accident and /or the engine stops rotating so the fuel pump does not feed a fuel spill fire.
Just use common sense and follow the logic.
Good luck.

 

Have you checked your fuel control module in the rear of the truck. That controls your fuel pump on and off