Won't start. No power at fuel pump!

[Ronger02]

2004 Ford Ranger, 3.0L V6, Automatic, 2 wheel drive, extended cab 4 door


Truck was running just fine. Took my daughter to daycare, went to work, went home for lunch, got back in the truck to go home and it cranked but would not start.

I could not hear the fuel pump turn on, so I sprayed starting fluid down the intake and it ran for several seconds, so I confirmed that the problem was fuel delivery.

I checked the under hood fuse box according to this diagram:
http://www.ranger-forums.com/genera...-need-replace-link-port-data-port-fuse-86928/

Fuse #23 tested good
Relay #48A - the part numbers on the sides of several of the relays matched, so I just swapped #48A with I think it was #46B. It still wouldn't start, and the washer pump still worked, so I guess the relay was good (is this the best way to check a relay?)

I wanted to check for power with a voltmeter at the pigtail plug on top of the gas tank, but I could not reach it well without dropping the gas tank and at this point I was pretty sure the fuel pump was bad anyways. I dropped the tank, and pulled the pump out.

With a couple of wires, I applied power directly from the battery to the fuel pump and it works! not sure if I am supposed to be pissed or happy at this point.

Put the key in the ignition and turned it on, got under the truck with the voltmeter and I checked for voltage at the two pins inside of the plug that supply power to the fuel pump. NO POWER!!!

What am I missing? What do I check next? Please help!

 

[Spott]

Well, it's gotta be the wires or connectors between the relay and that fuel pump connector. First, clean the connections in the relay socket, and then re-test.

Next, try and follow the wires back from the fuse box; if you see any connectors in the wires then take them apart and check for voltage. Look for damaged spots in the wires. If everything looks good, then you'll have to make some piercing probes from something like sewing pins, and start testing voltage from the center of the wires. This way you can narrow down the location of the problem.

 

[txgocartB3000]

Maybe your inertia switch?

Ray

 

[alwaysFlOoReD]

I'm pretty sure that power is supplied for the first two seconds only, and if the engine isn't running by then, the power shuts off. You need to get a helper or use a buzzer. Another thing to check is the rollover switch. In the earlier rangers it was under the rug by the passengers left foot. I've also seen it behind the kickpanel passenger side.

 

[hondaxr650]

I'd definitely check the inertia switch on the pass. floor, just below the heater box. Throwing stuff onto the passenger floor or kicking them can trip them. I have an uncle who had his truck towed to the dealer for a no start while he was hunting and it turns out that he bumped the switch with the barrel of his rifle when he put it in the truck.

 

[Ronger02]

I didn't even think about the inertia switch. I will check that first!

Does anyone know the order of which the power for the fuel pump goes? from the battery, to the fuse, to the relay, to the inertia switch, etc...? Does the power go through the PCM?

I hate electrical problems

 

[alwaysFlOoReD]

Check the relay for the computer; eec or pcm. The computer controls the relay for the fuel pump. Also check the fuses for the eec/pcm.

 

[Ronger02]

Problem solved. The darn inertia switch got me too. Took everything apart for no reason. Just simply resetting the switch would have solved the problem.

I just wanted to post the fix to the problem, so hopefully someone else will be saved the hassle of dropping their fuel tank for no reason in the future. Just check the inertia switch on the passenger side under the dash!

 

[enjr44]

Just an FYI, no personal knowledge. I have been told by a respected member of this forum that once an inertia switch pops it will do it again and again and .......

So he suggests that you change it when you have time or you will be digging in there again and not on your schedule.