Fuel Pump Woes
 

Hello everyone, I have a 2000 XLT with a 3.0 gasoline engine. My fuel pump is not coming on. I have replaced the relay and the fuel pump itself, what should I do next? Thanks in advance

If I did that correctly, I'm getting 5 volts to 2 legs..does that make sense?

Yes, 5-8volts with key on is normal, that is monitor voltage from the computer, no AMPs just voltage

You should see Battery Voltage, 12.3 to 12.8volts, for 2 seconds after key is first turned on, then see the 5-8volts, until you cycle key OFF and then ON again

Fuel pump power runs like this

Battery-----fuse 23(engine fuse box)---------Fuel Pump relay(engine fuse box)----------(dark green/yellow wire)-------------inertia switch(in cab passenger side)---------(pink/black wire)------------Fuel Pump

So first thing is to test fuse 23, don't "look at it" TEST IT.

Next head to Inertia switch in the cab, check that its Red Button has not popped up, hook up volt meter there, turn key on and watch voltage meter, should go up to 12v then drop down under 8v

thanks for your response. I'll check that fuse. I had already looked at the inertia switch, it does not need a reset. Thanks again for your help, I'll let you know what I find

I hear nothing when they key is turned on. I have the bed completely off so it should be pretty easy to hear I would think. I'm going to check that fuse. Thanks for your help!

I must be missing something.. I don't see fuse number 23 in the engine compartment fuse box.
https://cimg4.ibsrv.net/gimg/www.ran...e7387ee24f.jpg
https://cimg1.ibsrv.net/gimg/www.ran...3e98c831fc.jpg

Isn't there a fuse box on the driver side dash when you open the door?

See attachment

Try Fuse #9 20amp, thats for 1999 fuse box

there is, but I can't see anything that relates to the fuel pump there. #23 isn't used

will do, thanks.. you mean in the interior compartment or the engine compartment?

If you're referring to the relay in the engine compartment box, I already replaced it

Engine bay fuse box #9, that passes the 12v from the battery to the Fuel pump relay slot.
You can pull out the FP relay, then with key OFF, test each slot in relay's base for 12volts, only 1 should have 12v and thats from fuse #9

When FP relay closes that 12v from fuse #9 passes on to the inertia switch

Here is what a standard automotive relay base looks like: https://www.delcity.net/images/output-for-a-relay.jpg

85 and 86 are used to turn relay on/off, to close it or open it

30 and 87 are used for the #9 fuse 12v
So one of these slots will have 12v with key off, doesn't matter which one, thats the #9 fuse power
The other one will connect to inertia switch wire.
So when relay is activated, closed, 30 and 87 are connected, you can do this with a jumper wire in those slots to test further

87A is not on all relays, so may or may not be there, but its not used in this setup in any case

Thanks so much for your help and I'm following what you are saying. I do have one slot in the relay base that has 12 volts like you said. My confusion now is exactly what you mean by fuse number 9. If it is the number 9 fuse on the inside fuse compartment, it's a seven and a half amp that is labeled to be for the brake switch. Nonetheless, it's not blown.
https://cimg7.ibsrv.net/gimg/www.ran...3e46ba7df5.jpg

I should also mention that the red button on the inertia switch it's not popped up so I assume that it does not need to be reset. When I jumped the 30 and 87 slot with a piece of wire I had no change in the condition. Fuel pump still not coming on

Fuel pump fuse is clearly #9 in the engine compartment. Maybe the part that has you confused is that it is labeled in your book as 'Fuel Pump Relay and RAP Module'. R F Veteren has given more than enough info to trouble shoot this but I will add this -The engine computer turns the fuel pump on and off. When you first try to start the engine the computer turns on the pump on and if the engine does not start in two seconds it turns the pump back off until it does start. Some engines look for a good cam shaft position signal to know when the engine starts and then it turns the pump on. The computer sends a lower voltage to the relay to turn the pump on. This all means if you are checking fuel pump voltage you most anywhere you have to either have the meter in place where you can see it while you turn the switch and can see the two second current. Hopes this makes sense...

Engine bay fuse box #9

it does. And I finally get it, I was confusing the number 9 fuse with the fuel pump relay which is also marked number 9 in the engine compartment box. That fuse is testing okay..I hate electrical

In retrospect I can see that this has been coming on gradually. I thought maybe I just had a dirty injector or something. Could it be a bad ground somewhere?

I think I said that I get 12 volts to 1 slot in the relay base with the ignition off. Are you saying to put the meter on the number 9 fuse and turn the switch on and see what it reads, if that's possible?

The relay probably has a always hot supply voltage that you’re reading. That’s good and eliminates several potential issues but it’s not where we need to check next. You probably won’t be able to check the fuse and turn the switch at the same time. You’ll need somebody to help or you’ll need some more stuff, like a jumper wire etc... best if I get a wiring diagram. From a fix a car problem this should be an easier diagnosis than many other issues... I’ll post a wiring diagram after while. p.s. don’t hate electrical, hate ford fuse boxes :)

I really appreciate your help. I pulled the #9 fuse and my meter says it receives 11.4-11.8 v with the switch on or off, for what it's worth. Thanks again!