Ok, to start I have just acquired a 1999 Ford Expedition Eddie Bauer Edition, 5.4L 2V(16V) Triton V8
4R100 transmission, 2WD
With 142387 miles on it.

Purchased the Expedition at auction. When trying to drive it home it was running smoothly at first, it stumbled once, then ran smoothly again. I got a little farther down the road and it lost power, RPM's less than 500 no matter the throttle position. I pulled up to a light and it died. Got it started again, no power, barely running. Barely got it into a gas station, put gas in it. It wouldn't start again. Pushed it out of the way at the pumps. Waited a while, got it started again, seemed to be running normally. Pulled it around to a parking space at the back of the gas station, this is a gas station where there is a garage. It died again. Left it overnight and came back in the morning to make arrangements to have it checked out. Left it with him. During the time he had it, it would start every time and run normally. Until I went to pick it up, then he could not get it started. Left it with him again and he couldn't find the problem. He suggested that it might be the fuel pump and that he would change it, for $600.

I had it towed home. The tow truck driver drove it up onto his truck and drove it off of the truck when he got it here. The next day I drove it the gas station, put gas in it and drove back home. I also let it idle for a couple of hours. It ran normally the whole time.

The next day it wouldn't start. It has not started since. I ordered a fuel pump for it and installed it.

No start!

No CEL
Theft light operating normally, no rapid flashing
New fuel pump assembly
New fuel filler hose (the old one was bad)
New air filter (it needed it)
I still need to change the fuel filter

I have been trying to figure out why it won't start. As I couldn't hear the fuel pump operating I started checking the electrical. Below is what I found so far.

I unplugged the fuel pump then turned on the key.
I then plugged the fuel pump in, no sound or vibration from the gas tank. Unplugged the pump.

Voltages are to ground unless otherwise noted. Key was on during these measurements. The fuel pump was unplugged.

Battery voltage 11.85 V
Fuel pump relay socket voltages
85 - 11.75 V
86 - 0 V
37 - 6.56 V
30 - 11.75 V

30 to 37 - 5.17 V
85 to 86 - 11.56 V

The relay clicks when plugged into the 302 (Trailer Tow Battery Charge relay) and 304 (PCM power relay) sockets, but not when plugged into the 301 socket (fuel pump relay socket.)

The voltage on the pink/black wire at the fuel pump plug (fuel pump unplugged) is 6.45 V to ground or to the black wire, with the relay plugged in or unplugged.

Fuel pump fuse (fuse 10) is good visually and measuring voltage through it with a DMM.

Inertial fuel shut-off rings out good.
Voltage to the fuel pump on the pink/black wire with the shut-off unplugged is zero. The voltage on the dark green/yellow wire is 7.2 V. (I hooked up a battery charger.) This wire goes to terminal 37 on the fuel pump relay and to the PCM.

So there seems to be two problems with the fuel pump power.

One - insufficient current to operate the relay. Ground for the relay is being provided by the PCM. Power for it is being provided by the PCM power relay. The PCM power fuse (#24) is good.

Two - the dark green/yellow wire coming from the fuel pump relay (terminal 37) and PCM, and going to the inertial shut-off switch is making contact with a wire with power on it, or the PCM is putting power on this wire. Of course, this may be normal operation.

Does anyone have any ideas?

 

Oh yes, if I spray starting fluid into the intake it will start, then die when the starting fluid runs out.

 

Have you checked for fuel pressure at the fuel rail schrader valve ? Put in a new fuel filter if you don't know when it was last changed.

 

Looks like this Cloudflare thing ate my whole response to you.
I'm not going to try and retype the WHOLE thing back in.

Just to summarize, when you turn the Ignition Key to "ON", the PCM only powers the fuel pump circuit for ~2 seconds to prime the pump.
So you gotta be quick if you are trying to take voltage readings

Also, when you turn the key to "ON" the CEL should turn on.
When you turn the key further to the "START" position, and the starter begins to crank the engine, if the PCM detects the CKP (Crankshaft Position) sensor signal, the PCM will turn the CEL off and repower up again the fuel pump circuit.

Does your CEL lamp turn on during the bulb check and turn off while cranking the engine.\?

(Also, don't you mean pin 87 and not 37 for your fuel pump relay?)

That's enough. my typing finger is getting tired again. ;-)

 

Thank you Hamfisted for your reply.

No, I hadn't checked the fuel pressure, as I didn't have a pressure tester at the time. I now have one.

Before changing the filter, I checked the fuel pressure, it was at about 8 psi. Changed the filter. Turned on the key, no increase in fuel pressure, 0 psi.

Cranked it over and started it, the pressure picked up to just under 30 psi, then the pressure dropped to under 10 psi and the engine died. The fuel pump does come on when the key is turned on. Fuel pressure is currently 0 psi.

 

Thank you pdqford.

I was unaware of the time limit in performing voltage tests. As I was working by myself it was impossible to check them. My middle name is not "Quick." I move about as fast as molasses in the winter. When I got some help, I was able to verify the voltages, they were all good.

About the CEL, I actually have an SESL (Service Engine Soon light), it comes on when the key is turned on and goes out when the key is turned to Start. If the engine starts the light stays off. Otherwise, it comes back on.

You're right it is 87 and not 37. My eyesight isn't what it used to be, even with readers.

See the pdf for codes.

 

Would this happen to be the fuel pressure regulator? It is attached to the fuel rail, upper tube.

 

Yes ....


Motorcraft CM5296 at Rock Auto

 

Thanks Hamfisted.
Nice to know. Although I can't see how it's held in unless it's a press-fit.

 

Ok, here's what I have today. I did a fuel pump flow test, tank bolted in and tank lowered.

The bottle on the left is with the tank bolted in place. The bottle on the right is with the tank lowered, front strap loosened, rear strap removed and the fill hose disconnected. Both tests were through the filter. About equal amounts of cranking time.

 

The fuel pressure regulator has a big C-clip inside the largest circular area there. Might have to take a good flashlight and mirror to find the ends to latch onto with snap ring pliers. Do you ever hear a big vacuum relief sound when you take your gas cap off ? Just wondering if that could account for the difference in fuel flow you're seeing there. But whatever it is, you need 45-55 psi at the fuel rail. What kind of fuel pressure are you seeing with the tank lowered ? ( I assume the gas cap is off if the filler pipe is loose .... )


Here's a how-to video from YouTube on the fuel pressure regulator removal ....

 

No, I don't hear any sounds of the pressure being equalized.

Currently, the fuel pressure is at 18 to 20 psi, at idle, or revving the engine. If I disconnect the vacuum line to the pressure regulator the pressure will come up to all of 22 to 24 psi.

This is after adding 5 gallons of gas. The gas gauge was reading between 1/8 ànd 1/4 tank and the Low Fuel light was on. The truck was also sitting on ramps at the rear. It is now at about 3/8ths tank. When I got it, the gas gauge was reading 1/4 tank, I drove it for less than a half-mile, when it lost power and died the first time.

Before adding the gas, I cycled the key on and off a few times. The fuel pressure was 6 psi, at that time. After adding the gas I cycled the key again and got a fuel pressure of 22 psi. Then I started it, whereupon the pressure dropped to the above values.

I just took it for a 4-mile drive. It was running smoothly, with enough power to spin the tires. No problems so far, I'll have to see what happens now.

 

If that's the best fuel pressure you're seeing at the rail I'd look at replacing the fuel pump and not wait for it to leave you stranded.

 

It's a brand new Airtex pump. It's one of the first things I did.

 

Oh ok. I missed that in your earlier post. The volume test you did earlier with the bottles. Was that just taken off the fuel filter outlet ? Airtex is usually a good pump. Only thing left I guess is the fuel pressure regulator if you feel like throwing a new one on. But as long as you're happy with the way it's running, that's all that really matters.