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Discussion Starter · #1 ·
2002 F250 crew cab short bed, no tuner, 5" exhaust (came with truck) 277k on it, rebuilt trans with heavy duty tc. Ok here it goes. On Saturday I was almost home (.3 miles from the house) on a back road when going up a slight incline and heard some tapping I'd never heard from the engine as I was accelerating. I took my foot off the gas pedal because I had to go around a tight turn then go up another hill. I felt a loss of power and started pushing down on the gas pedal more to get the rpms up but I was losing power and eventually the engine died and wouldn't start back up. What made it worse was being so close to home with 2 little kids crying in the back and having to call my wife to come pick them up.

I immediately thought it was a fuel problem. I had a fuel pump on an explorer die like that on the next block over before I got home. I had maybe 3/8 of a tank left so I wasn't low. I've had the truck for maybe 40-45k miles. I'm the 2nd owner. I started by opening the drain valve on the fuel bowl and some diesel came out. I initially thought the fuel pump might have gone up or the fuel filter was clogged. While I was waiting on a friend to come with some tow chains I ran to the parts store and grabbed a fuel filter and fuel pump. Towed it back and next day I changed the filter first. A lot of junk in the fuel bowl and it must have been blocking the drain valve because I still had about a half full of diesel when I opened the cap. I'm assuming the bowl was full when the truck died because I dumped some but there was still plenty in the fuel bowl. Drained the fuel bowl, took the fuel heater out and cleaned all the crud out including some of the line with a q-tip. I reinstalled the fuel heater and new filter.

Silly me didn't think to initially check for voltage at the fuel pump. I guess I just assumed it died and so I disconnected it and put the new one on; much more of a pain than I thought it would be. I didn't find much fuel in the inlet line from the tank or the outlet to the fuel bowl. Finally after replacing the fuel pump I went to start and it. I primed it 4x for 30 sec with the key in run position. Started it but it took some cranking and it ran extremely rough with low idle unless I hit the pedal then it died. I'm guessing this was the fuel in the injectors. Opened up the fuel bowl to find no fuel. I figured at that point since I didn't have a stream of fuel going into the pump I might have a restriction in the line or a clogged tank screen. I had to let the truck sit for 3 days because of work.
Today went to check voltage and I don't have anything at the fuel pump. Checked fuse #40 and it's good. I've checked #36, 105, 110, and 116 and all are good. I did continuity on them and still nothing as well as the relays under the hood and new fuses just incase. Did continuity from pins 30 to 87 and all were fine. I checked voltage on fuse side of fuse panel for #40 and got 12 volts as well as some of the other fuses. Had my wife turn the key on while I was under the truck and didn't hear anything. I swear though I thought I heard the pump run this morning when I turned the key to the on position but the fuel bowl was still empty. I jumped the pump from the battery and the pump worked so I opened the drain on the fuel bowl and powered the pump. I saw fuel come out without a problem so that took the restriction off the list. I shut the valve and filled the fuel bowl. Tried to start and if I remember I think it started but not for long because the pump wasn't powering.

I'm not sure where to go next to figure out how to get power back to the pump. Before it died I was driving it all day around town with the kids with no problem. It just lost power and died. Does anyone know or has seen could it be the CPS, IDM, ECM. I've also checked the oil. it's within operating level at cold and the HPOP has oil in it. Enough that the hex drive I used to open the hole and look inside I dipped in to make sure it was filled. I have all the WTS lights (glow plug, water in fuel, etc) which should indicate the ECM is ok correct? I haven't noticed the tach move when trying to crank but if the CPS is bad would that affect voltage to the fuel pump?

I only have a generic code reader and it wouldn't read anything plus I don't have a CEL. I've checked all the fuses and can't seem to find a blown fuse. The fuel shut off switch (inertia switch) doesn't seem to be popped up. I put dielectric grease in the connector for the tail that powers the fuel pump. I'm stumped and could use some help on what to try next. I've got to work out of town next week so if I don't fix it tomorrow or Saturday I'm a little screwed for work the following week. I do all my own work for the most part but I don't have a good mechanic I trust to work on the truck and I'm not taking it to the dealership.

I've had this truck for about 15 months and continually learning the 7.3. Not my first diesel either but I'm stumped. Thanks in advance for any help.
 

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The only thing I can think of that you didn't check is the fuel pump relay. Unfortunately, on the 02 and later trucks, it's built into the Central Junction Box and not replaceable. The relay coil is energized when you turn the key on and sends power from fuse #40 thru the Inertial Fuel Shutoff Switch to the fuel pump. Have you checked that you have power with the key on at terminal #10 of the CJB? The PCM grounds that terminal to energize the relay for 20 seconds or so when you first turn the key on and then off, but keeps it grounded if the engine is running. So to test the fuel pump relay coil, turn the key on, wait for a minute or so and see if there's 12V on terminal #10. If not, that would mean the coil is open and can't pull the relay in to power the pump.

If I was in your position right now, needing the truck. I would wire a switched power circuit to the fuel pump temporarily. You'd have to be careful to turn it off when you shut down the engine. Maybe that will give you enough time to track down the problem.

Good Luck
 

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Discussion Starter · #3 ·
I'll do that today. I have 12 volts at fuse #40 on the fuse side. At the minimum I'll have power to the fuel pump and if I have another issue I'll have to trouble shoot it. Also I think I forgot to mention I unplugged the fuel heater just in case. When I run winter blend I add diesel entire additive to every tank to keep the fuel from gelling. Will keeping the fuel heater unplugged during the winter have any negative effects during the winter? Also should the heater cool be snug or should the screws be out some so the spring allows the coil to move up and down. Initially I put the cool back in right and then loosened it back up. If I remember correctly before I removed it to clean the fuel bowl out I could tell there was a spring because I could push the filter down but I could feel the resistance on the spring.
 

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I'll do that today. I have 12 volts at fuse #40 on the fuse side. At the minimum I'll have power to the fuel pump and if I have another issue I'll have to trouble shoot it. Also I think I forgot to mention I unplugged the fuel heater just in case. When I run winter blend I add diesel entire additive to every tank to keep the fuel from gelling. Will keeping the fuel heater unplugged during the winter have any negative effects during the winter? Also should the heater cool be snug or should the screws be out some so the spring allows the coil to move up and down. Initially I put the cool back in right and then loosened it back up. If I remember correctly before I removed it to clean the fuel bowl out I could tell there was a spring because I could push the filter down but I could feel the resistance on the spring.
If you're talking about the post inside the fuel filter housing, the screws should be snug. They hold the heater coil in place and also the center post. You probably have the solid coil fuel heater, so is isn't the danger of breaking like the older wire and button style was. Check this post for more info. http://www.thedieselstop.com/forums/f47/shorted-fuel-heater-fixed-239318/ The only thing the fuel heater failure will do is blow the fuse that also controls the PCM power relay, and if that doesn't activate, the PCM won't power up and the engine won't start. The heater is there to keep the fuel in the filter from gelling and blocking flow. I think it's just insurance, but a good thing to have active. Like I said, if you have the heavy duty fuel heater, I doubt you'll have a problem with it blowing the fuse.
 

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Discussion Starter · #5 ·
Well I installed a toggle switch and ran power to the pump directly for the moment. Since I had filled the fuel bowl when I tested the pump directly and tested it with the drain open before that it cranked right over. I ran it for maybe 20 min before I shut it off. Started it back up and took it for a test drive. It seemed normal.

I still checked the #40 fuse again and it has power. The fuse had continuity as well. I took a wire and placed it in the fuse slot just incase for some reason when I was metering power at the front side of the fuse panel with the leads I loosened the connection for the fuse. Still nothing. It has to be an electrical gremlin in the wiring running in the harness. The wires going to the fuel pump relay on the driver's side are pretty cruddy so I couldn't yet tell which one it is. For the time being it will work.

It just doesn't make sense that the pump died or at least it appears to have died and then an electrical problem appeared after that at the same time. Not the first time I've encountered something else when having a problem. Thanks for the toggle switch suggestion it was a big help.
 
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