99 & up 7.3L Power Stroke Engine and DrivetrainDiscussion of the 99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
The injector relay is for the IDM- Injector Driver Module. The IDM provides power to the injector solenoids- it has nothing to do with fuel supply.
A quick test of a relay is to swap it with a known good one- such as the horn relay.
Now I have power to the leads that go to the pump. (yes I am going crazy)
The power to the leads shows about 15 volts for about 20 sec then drops to 10 volts. (This is a cheap meter from the rental fuel pump kit my fluke 87 has a bad screen and hard to read, it reads different)
Jump pump with 12V battery it pumps Through the drain valve
use jumper wires to connect leads from car to pump and I get nothing. can't read voltage, pump doesn't pump.
When I cycle the key and the voltage drops I feel a click in the starter relay.
Again hook up the pump direct to a battery and ran pump started truck and it ran. Diesels run rough compared to gas. This seemed to stay running. I shut down, did not know what would happen if I keep pump on constant.
Could it be PCM relay?? Earlier post referred to pulling this and if HPOP problem truck might run. Wiring diagram had pcm doing something in the circuit. If that was bad I don't think I would see power at the leads.
Then I don't understand why I am getting power at the leads to the fuel pump but it won't run the pump.
Just a thought but are we sure it is a fuel proplem. A lot of things can keep it from starting have you checked the sensor on top of the HPOP resvory, the HPOP or the IPR sensor. All of them and several others could cause this problem.
Do you have anymore info on these sensors and the symptoms they cause
Sensor on top of the HPOP reservoir is the LOW pressure oil gauge sender (actually just a switch).
The ICP sensor (located just behind the alternator on the driver's side head) controls the HP oil pressure sent to the injectors to operate them. If it's whacked out it can cause a no-start or rough running. Pulling the wiring connector to it causes the PCM to go to default mode and may smooth out the rough running by using other parameters to control HP oil pressure.
I really think your issue is fuel delivery, so I would recommend you not get side-tracked by those things right now.
Back in a minute or two with wiring info for the fuel pump circuit.
OK, here's the wiring info on the fuel pump circuits
From Fuse #64(30A), power goes thru a dark blue/orange wire to the ignition switch, out of the ignition switch (in start and run) power goes thru a red/light green wire to the fuel pump relay control coil. Out of the control coil, a light blue/orange wire goes to the PCM which provides a ground to complete the circuit and pull in the fuel pump relay.
The power side of the relay (switching contacts) starts at fuse #40 (20A) and goes to the input side of the relay, out of the relay, a dark green/yellow wire goes to the inertial fuel cutoff switch, and from there, a pink/black wire goes to the fuel pump. A black wire goes from the fuel pump to ground.
The fuse block diagram I have doesn't show the fuel pump relay , but the wiring diagram lists it as K4. Maybe there's a marking on the fuse/relay panel where it plugs in. If all else fails, you can identify it by checking for power at each relay socket, then pull fuse #40 which will kill power to the FPR.
A couple of specifics you should check:
Check that the PCM is closing it's relay to complete the FPR circuit. Use an ohmmeter between the relay socket coil terminal and ground and see if it closes when you turn on the key. It's possible that the PCM has failed on that circuit.
Check the ground wire for the fuel pump. If it's open (disconnected or broken), the pump won't run. on edit: tbpower beat me to the punch on that one while I was typing this out.
If anything has been added to the truck's electrical system using fuse taps at the fuse box, it may have spread the fuse holder contacts, making the fuse contact intermittent. If you have a spade type wiring terminal you can use that to check the grip of the fuse holder on both upstream and downstream contacts individually (the fuse with both spades may mask a loose contact).
As far as checking relays, you can just swap positions with them and see if there's a difference.
...starts at fuse #40 (20A) and goes to the input side of the relay, out of the relay, a dark green/yellow wire goes to the inertial fuel cutoff switch, and from there, a pink/black wire goes to the fuel pump. A black wire goes from the fuel pump to ground.
Found the first part of the wiring diagram at another site. The colors are great. THe hot to my fuel pump is red or orange. definitely not pink/blk. Think I will remove the kick panel tomorrow and look at the wires.
Quote:
Originally Posted by klhansen
...The fuse block diagram I have doesn't show the fuel pump relay , but the wiring diagram lists it as K4. Maybe there's a marking on the fuse/relay panel where it plugs in. If all else fails, you can identify it by checking for power at each relay socket, then pull fuse #40 which will kill power to the FPR.
My owners manual doesn't reference and FPR either. It is not listed in the fuse or relays list either. Another post stated that it might be behind the radio. But the drawing I have indicates that it is in the control junction box. It also lists fuses that I don't have. Sure hope I don't need to remove the radio.
Quote:
Originally Posted by klhansen
...Check that the PCM is closing it's relay to complete the FPR circuit. Use an ohmmeter between the relay socket coil terminal and ground and see if it closes when you turn on the key. It's possible that the PCM has failed on that circuit.
Any idea where the PCM relay is?
Thanks for the info. My eyes are crosseyed. tomorrow night I plan to check all fuses and look at the wire colors around the fuel shutoff.
I believe I can run the truck with battery power to the fuel pump. Whould like to get it into the garage.
Strange. I was getting the info from the Ford Service CD for a 2002 F250/350
Quote:
Originally Posted by newtrucklady
My owners manual doesn't reference and FPR either. It is not listed in the fuse or relays list either. Another post stated that it might be behind the radio. But the drawing I have indicates that it is in the control junction box. It also lists fuses that I don't have. Sure hope I don't need to remove the radio.
The service manual wiring diagram indicates it's in the fuse/relay panel not behind/below the radio like the earlier trucks, sol don't worry about that. What I was trying to say is that with the key off, the upstream switched contact of the FPR will be hot with #40 fuse in place. So you could determine which is the correct contact by looking at the pinout diagram that should be on the relay, put your voltmeter on that terminal in the relay socket, then pull fuse #40 and the meter should go to zero if you're on the right relay.
Quote:
Originally Posted by newtrucklady
Any idea where the PCM relay is?
The relay I was referring to is solid statge and internal to the PCM. Once you find the right relay, put one lead of your ohmmeter on the downstream switched contact of the FPR relay socket and the other lead on a ground, and it should read infinite or very high resistance with the key off (PCM unpowered), then when you turn the key on, the resistance should drop to a very low value for 20 seconds or so, then go high again. (the PCM turns the fuel pump back off unless the engine is started).
Quote:
Originally Posted by newtrucklady
Thanks for the info. My eyes are crosseyed. tomorrow night I plan to check all fuses and look at the wire colors around the fuel shutoff.
LOL, I can understand the crossed eyes. Electrical troubleshooting can be a PITA.
[quote=klhansen;1846451]Strange. I was getting the info from the Ford Service CD for a 2002 F250/350[quote]
perhaps that fuse is somewhere else in the truck. Owners manual only shows what is in the fuse box.
Believe I found the FPR, under hood on driverside by firewall. The relays seem hard to come out. Do you just pull them out? don't want to break anything
.
Atleast the truck in now in my garage out of the wind and cold.
Strange. I was getting the info from the Ford Service CD for a 2002 F250/350
perhaps that fuse is somewhere else in the truck. Owners manual only shows what is in the fuse box.
Believe I found the FPR, under hood on driverside by firewall. The relays seem hard to come out. Do you just pull them out? don't want to break anything.
On an 02, there should be only one fuse/relay panel, under the instrument panel. I can double check for that fuse # this evening when I get home.
If you found relays in a small double relay box under the hood, those will be for the trailer tow package (Trailer Battery Charge and Trailer Backup light relays) and for the Electric 4x4 Shift motor (One to go to 4x4 H & Low and one to go back to 4x2). Relays can be tough to pull out, because they have 5 spade terminals. Just pull harder. (But I don't think anything under the hood is your FPR).
To make a long story short, I believe it may have just been a series of things coming together..
The fuel gels and causes the truck to die, the suction line on the pump starts leaking air and air binds the pump so the filter bowl will not fill. Then, once the pump is reinstalled, a poor connection prevents the pump from running. Trying to put car power to it with jumper wires resulted in too much voltage drop. Needles to say when I got under the truck and reconnected everything, and a friend came over to turn the key for me, the pump ran.
So I believe the solution, after the gelling fuel, was replacing a leaking suction hose.
Thanks for all the coments and suggestions.
BTW I never did find the FPR or PCM And hope I never need to. But I will keep looking.
Well my truck did same thing but I know the pump is working it's just not filling the bowl. Howong did you have to leave it in the garage to get the fuel line to unjell and what lline was leaking? I ve had it in heated garage for coue hours still no fuel.
__________________
2000 psd
doing exhaust and removing butterfly
I do not think that the line gelled. I never had it in a heated garage. If you are sure that the pump is running, then perhaps the suction line is sucking in air. Pumps do not like air.
The hose I replaced was the suction hose. It is the hose attached to the rear of the pump, should be just over a foot long.
Good luck
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), AIS, 
, but the wiring diagram lists it as K4. Maybe there's a marking on the fuse/relay panel where it plugs in. If all else fails, you can identify it by checking for power at each relay socket, then pull fuse #40 which will kill power to the FPR.
Linear Mode
