2004 Navigator Fuel Relay/Pump Voltage Issues Crank No Start

[tedallen]

Hello. I posted about this issue in the Lincoln Forums and have had responses there from a couple of folks, but this forum has been much more active in the past, so I'm going to cross-post here.

I replaced the central junction box in this vehicle in February of 2018 due to a failure of the fuel pump relay. A couple of weeks ago, when I got in it after a doctor appointment it failed to start. The first crank or two there was a little sputtering, but not much. I had it towed home and when I started testing (I confirmed it was a fuel delivery issue when it started with starting fluid), I was initially seeing 12+v when back-probing the DG/YW wire in the blue-outlined connector on the central junction box (CJB) in the passenger front kick panel. However, it was dropping down into the 6v range in less than the 2 second fuel pump prime period when the key was turned to the KOEO position. I tried jumping 12v from the battery directly to the DG/YW wire in the connector and still did not hear the pump run.

I then took out enough rear trim to get to the inertia fuel shut-off switch and disconnect the connector and check the voltage there. It was reading the same as at the CJB.

At some point during testing I was no longer seeing even a momentary reading in the 12v range on the DG/YW wire at the CJB or inertia switch. At this point I decided to order replacement relays (a 2 pack) and removed and disassembled the CJB. I noted a burnt swollen section on the relay and felt confident I had found the issue.

However, after desoldering the old relay, soldering in the new one and installing the CJB back in the vehicle the symptoms remained the same. I was still only getting 6v on the DG/YW wire when back-probing at either the CJB or inertia fuel shut-off switch.

Even when running 12v directly to the DG/YW in the inertia switch connector (with it disconnected), I still do not hear the pump run and the vehicle will not start.

It seems like there is another issue impacting the voltage coming from the CJB even after replacing the bad relay, and it seems like there is quite possibly a problem with the fuel pump (or at least somewhere in the path between the inertia switch and the fuel pump) as well.

I replaced the fuel filter before I replaced the relay in the CJB while I knew it was not under pressure. I went to my local Pull-a-Part and got a complete CJB out of a 2004 Expedition today and am going to install it tomorrow and see if it behaves any differently.

Is there something else that could be influencing the voltage on the DG/YW coming out of the CJB (e.g. PCB)? Does anyone know which wire and (in which connector) the incoming power that should be going across the high voltage switched side of the fuel pump relay would be on and what components are in the chain that supplies that voltage?

I know @Hamfisted had a post 4 or so years ago where he mentioned having had to replace his CJB for the second time. It looked like he replaced it with one that was manufactured in 2020. Would that have been a special build replacement (aftermarket) or were Expys still using a common CJB that many years later? I would find that hard to believe.

I greatly appreciate any and all assistance.

Ted

 

[whtbronco]

I suspect you have a poor ground or corroded connector somewhere in circuit causing the low voltage. The fuel pump itself may or may not have failed.

I'm not sure where I found this, but it seems appropriate to try in your case.
For some FORD models:
1. Disconnect the inertia switch harness connector
2. Turn key to ON position (Engine OFF)
3. Measure voltage of circuit between inertia switch harness connector and ground
4. If battery voltage is found, replace Inertia Switch
5. Clear codes.

Attached are some of my notes and screenshots from when my fuel pump relay failed.

@Hamfisted replaced his CJB a 2nd time with an OEM unit that was produced with an upgraded relay, it was not aftermarket. Here's a comment from him "I just replaced mine again for a different reason two years ago and it came with the Panasonic micro relays."

 

[tedallen]

Thanks @whtbronco . I verified all of the fuses (and moved over additional ones I needed) in the CJB I got from Pull-A-Part yesterday and the behavior changed. I do see12v briefly on the DG/YW wire at both the connector and at the inertia switch connector. It definitely isn’t for 2-3 seconds. However, when cranking the engine I am now seeing 12v while cranking at both locations, but the pump does not appear to run. One of the guys on the Lincoln forums mentioned the possibility of the PCM controlling the ground signal to the pump. If that is true for my vehicle, I don’t know where to test to see if that ground is being completed by the PCM. I guess the next thing I am going to do is see if I can gain access to a connector going to the fuel pump that includes the power coming through the inertia switch as well as a ground to see if I can determine anything there.

The wiring schematics you supplied match with the ones in the digital service manual I purchased back in 2022. However, those do not match with my vehicle, even though I ordered the service manual specific for my VIN number. I believe my vehicle was produced early in the 2004 model year (8/2003) and they made a mid-year change in the fuse panel. For example, my owner's manual shows the fuel pump protected by F1.34, not F1.9. In fact, F1.9 is empty on my vehicle. F1.34 protects the PCM, IAC solenoid, MAF sensor, fuel injectors, fuel pump relay, fuel pump shut-off switch and fuel pump motor according to my owner's manual and I have confirmed that the fuel pump and fuel pump relay are definitely being protected by F1.34. I think I may need the wiring schematics for a 2003 model year Navigator. I contacted the company I purchased the service manual from and they stated they provided the correct wiring schematics for my VIN, but I know they are not correct.

Thanks,

Ted

 

[whtbronco]

I wondered if the Navigator would be a little different in this case. The CJB varies a fair amount it seems. As I'm sure you are aware there are some differences.

The best place to test I would think is the fuel pump module connector which you noted you are gonna try. I'm not sure if you can get to it without dropping the tank a little bit. I struggled to get the various hoses and wires disconnected and then connected again on the tank.

The fuel pump connector is just 4 wires. If yours is a 4 wire module then it looks like 1 of the 4 wires goes to G300 for ground and not the PCM. G300 is behind the B pillar trim on the Expedition.

This is certainly an odd one. My relay also failed a few years prior to the pump. I'm inclined to think it's the fuel pump and if you get the pump connector separated it'll be interesting to see what you get for voltage.

 

[tedallen]

Thanks @whtbronco I actually got the replacement CJB from a 2004 Expy yesterday. It had a month or so different manufacture date than the one that was in the vehicle when I replaced it in 2018. The suffix of that part number is an AB I think and the ones I had previously were AD and AE.

I don’t know if the fuel pump has ever been replaced, as I bought it in 2016 at 154k miles to replace a 1997 EB Expy at 342k miles. I did replace the fuel pump in the Expy.

My vehicle does not have the separate fuel pump driver module mounted on the driver’s rear frame rail. You mention G300. Is that just a ground screw/bolt into the body?

Unfortunately the vehicle is outside and we have cold weather for the coming week. I hope to find out something more tomorrow.

 

[jmkendrick]

I screwed around for quite awhile on my 2004 Expedition checking voltages thinking the fuel pump relay was a problem. Finally went old school and smacked the bottom off the tank with a dead blow hammer a few times and it started right up. Only worked once though so don't count on it lol.

 

[tedallen]

Thanks @jmkendrick lol. I actually have the vehicle in my driveway, so I definitely want to get to the root cause(s) so I don't get stuck with a tow bill again. I might try the hammer just to see if it changes the behavior though. If it does make the pump start to run that would be a pretty good indication I need to drop the tank (which I am going to try to start doing today). It looks like you are in KY (or were when you joined). I grew up in northeastern KY along the Ohio river (near the little city of Vanceburg) west of Ashland and NE of Morehead, went to WKU and lived in Louisville for about 6 years in the early to mid 90s working at the Ford Medium/Heavy truck plant (installing the new CLT production line) before relocating to the Charlotte, NC area in 1998. Looks like you are close to Cincy. Are you a long suffering Bengals and Reds fan as well?

@whtbronco it does look like the G300 ground is behind the B-pillar on the driver's side. I may try removing that trim panel before I drop the tank just to make sure that ground looks good.

 

[tedallen]

I couldn't see a way to access the fuel pump connector without lowering the tank, so at this point I'm going to try to remove it completely and replace the fuel pump and check wiring to it with the tank out of the way. The service manual says to remove the straps, lower the front of the tank about 1" and then remove the rear driveshaft. Is it really necessary to remove the driveshaft? I saw a guy doing a fuel pump replacement on a 2003 Navigator and he didn't remove the driveshaft. I haven't been able to get the rear strap unhooked from the slot because there isn't a lot of room to rotate it between the tank body and the driveshaft. Maybe that is at least one reason why the service manual says to remove the driveshaft. I think the guy in the video just bent the straps down instead of removing them (at least until the tank had been lowered a good bit.

 

[whtbronco]

It can be done with the driveshaft in place. I found it much easier to have removed it though. I lowered the tank and moved it over some so I had room on both sides of the tank to work on disconnecting stuff.

I put in a Bosch pump a year ago. I've had good luck with Bosch in the past, this item not so much. The pump still works, but sounds a bit odd. The issue is the fuel level sender is no where near accurate. It shows full even with 5-6 gallons burned and then the last 1/4 is good for less than 50 miles. So it's way the heck off. It is also a slightly different design than most of the others. This is on my list to address this year and I am debating getting a free Bosch replacement or a Delphi pump since it matches the OEM design. I can't find an OEM pump now.

 

[tedallen]

Thanks @whtbronco sonyou did remove the driveshaft? I have the fuel pump electrical connector, the filler neck hose and the tank vent hose left to disconnect, which I have heard is a pain to get to and is clamped on with a 6mm head bolt.

If you removed the driveshaft did you have issues getting it loose and then back in? Did you remove it completely at both ends? The service manual shows a specific area to pry on the rear connection and says not to use a hammer. I noticed grease/sludge all over the rear differential housing which I suspect must be coming from a seal where the driveshaft connects. Have you ever tried to replace it? I need to check the manual to see if it can be replaced fairly easily after the driveshaft is removed. So, I just checked the service manual and it looks like replacing the pinion seal is more work than I want to take on right now. I need get the Navigator running. It requires removing wheels, calipers, etc. I'll plan on taking that on when it warms up in a couple of months.

I also noticed an odd trail of what seemed to be a thick grease along the fuel filler hose coming down to the tank.

Thanks for the info on the Bosch pump.I was actually trying to locate one of those since I hadn’t found a Motorcraft one. I think a couple places had Delphi in stock.

 

[whtbronco]

Yes I did remove the driveshaft. It's not too bad to remove really. It's much easier to jack up the rear end and have a helper hold the brakes to remove 2 bolts. The put the trans in Neutral, rotate the driveshaft, hold the brakes again and remove the other 2 bolts. 12mm 12 sided bolts. It just slides out of the transfer case or transmission. I pull the bolts out and then use a small crow bar as a punch against the pry area, along with a hammer to tap it off the diff. Put a paint mark on the driveshaft and diff flanges to line them up on reinstall.

Yeah none of it easy per se, but the vent hose is a royal PITA to disconnect. I took the spare tire out and with the tank lowered like 3-4" I was finally able to wrestle it apart. Putting it back was worse. Some of my issue is my hands are in bad shape.

Yes I have replaced the front seal on the rear diff. In fact I replaced it 3 or 4 times, and it always leaked a little again in just a few months. Until I replaced the u-joints with Spicer SPL series, had the driveshaft straightened and re-balanced. No more front seal leak. The same process on the front driveshaft resolved that leak as well. Neither leaked much, just enough to cover some of the diff with oil and dirt. That said just replacing the seal and putting everything back together without a new crush sleeve is not the approved process, but it is commonly done. You will need a way to hold the pinion flange still to remove and reinstall the pinion nut.

I'm not sure off hand what the grease near the fuel filter might have been.

 

[tedallen]

Thanks @whtbronco I actually have the Expy supported on 4 jack stands with all 4 wheels off of the ground, floor jack on one side as an extra safety and a transmission jack under the tank. The odd trail of grease was actually on the fuel filler tube going to where you would fill the tank.

It was very cold here yesterday and snowed last night and was very cold again today and tonight. I don’t know if I will get to work on it again on Thursday afternoon or not.

You mentioned replacing the crush sleeve when replacing the pinion seal on the rear diff. I don’t recall that being mentioned in the service manual. It looks like it would go between the two pinion bearings on the shaft. Is it removable after removing the pinion seal and bearing on the driveshaft end of the shaft without further disassembly of the differential? Did you replace the cover gasket (I think the OEM ones were supposed to be reusable and made of metal and a silicone or rbber material and aftermarket ones are not)? Did you use Motorcraft differential fluid in it?

Did you find a machine or specialty shop to straighten and balance the driveshaft? Where did you purchase the replacement U-joints?

Thanks for all your assistance.

 

[whtbronco]

Hmm, you're right the suggested process for the 9.75 inch axle does not suggest replacing the crush sleeve. That's unusual to me. Anyway, the good news it is too much work any and requires differential disassembly. I have not replaced the the cover gasket on the rear diff, that is a fair amount of work since the cover is the mount as well. I have never even looked into the rear diff cover gasket on the Expedition.

I use Amsoil fluids, 100% synthetic, in everything except for Prestone coolant and brake fluid. For the rear diff I use 75W-140 gear oil and since I have a limited slip diff I also use a tube of Amsoil friction modifier. You should not use anything but synthetic gear oil in it.

I got the u-joints from RockAuto, not cheap, but these are arguably the best u-joints available. The single kit replaces all 4 u-joints and comes with several different sizes of spring clips and I needed them to get the perfect fit.

More Information for DANA SPL1007FK

This tool works pretty well for removal and install of the u-joints. It's certainly better than a large C clamp or hammer which can easily bend the flange.

The local heavy equipment repair shop also does driveshaft straightening and balancing in house. It was $300 for the rear, $200 for the front. I could have done them cheaper with "cheap" aftermarket replacements, but no thanks I'll keep the original parts instead.