I'll start, with this novel I wrote.
My adventures have been spread out over almost a year. (I'm a busy guy and spread fairly thin.) That said, I love little more than coaxing recalcitrant old machinery back to life and hopeful reliability. So there was pain AND pleasure.
1. Bought and limped home a '93 460 Newmar. Seller said he thought the catalytic converter was stopped up and warned it would lose power as I went. He wasn't kidding. Idled beautifully but that last hill before home I was tempted to get out and push. Seller swore up and down he had replaced the entire fuel pump assembly with a genuine Ford assembly
2. It was NOT the catalytic converter. The exhaust system is just fine with no back pressure to speak. (It wants header though. I just know it.)
So I thought to buy a fairly generic replacement fuel pump online and a new sock filter. (Note, I am fairly hard-headed and a determined DIY'er). I added a big ground strap from a pump assembly bolt to the frame since whoever had been in there before had broken the old ground strap and neglected to replace it. All that seemed to help but power still was lacking. The pump I pulled out has spot rust on the outer housing and was obviously not very new. No traditional Ford part number stamping on it or in fact any markings on it at all.
3. Fuel pressure gauge from Harbor Freight that I have used for other things leaked fuel at the "Ford" adapter and I judged it unsafe. Tossed to the side. Kind of crippled my troubleshooting.
4. Found out 1991 or so E350 460 vans used external pumps. Bought one online. Ford part #D5UZ112155OB but it is some off brand replacement. Cut up the original Ford inline fuel filter (thicker metal than the off-brand replacements) and made quick connectors for the inline pump so I could swap it in place of the filter if needed. Seemed to work OK drawing fuel through the in-tank pump during testing but I can't imagine the in-tank pump NOT being a restriction to fuel flow nor that the inline pump wouldn't pose at least some restriction to fuel flow from the in-tank. Already apparently having troubles with over stressed pumps I chose to leave it disconnected in favor of the correct filter for the time being.
5. Took a short camping trip. Power dropped off some just as we arrived. On the way home power dropped dramatically. Stopped and installed the backup pump. Power regained but dropped slowly away again. Close to home I was limping along terribly slowly on some back roads. Happily there was hardly any traffic and the hills were going mostly down. Stopped a couple of times for shopping, ice cream, and such and having a cool off break seemed to help. The worst behavior was pretty close to home and within range of help if we needed it so not so worrisome. I told wifey I regretted not bringing the bicycles. We could unload hers and she could race me home with a fair chance of winning.
6. Later found the inner fuel sock of the in-tank pump to be pretty stopped up with what appeared to be rust. But I lost faith in the cheap pump anyway and tossed it. I was rather cynical about how it might perform to start with.
7. Went to buy what was listed as the correct lower pump complete assembly. (White plastic with pump inside). Got home with it and it resembled what I have not at all. No way it would fit. Didn't have provision for the generator feed either. But it sure looked familiar. Went to my spare parts shelf for my 1995 F150 and pulled out the box I marked "front tank". Blew off the dust and pulled out the EXACT same unit. After staring at it a bit I realized it wouldn't fit the F150 either. (I previously had stale gas issues with that truck). Blast. Disassembled it for a looksee to find the pump by itself couldn't be used in the coach either. Too different a design. Returned the new assembly for a refund and tossed the other back on the shelf to gather some more dust.
8. Word I found online is that the original Ford pump had a design problem and at some point should have been changed for another updated design. Also rumor had it the newer pump was made by Delphi. Found the local parts store had a Delphi brand pump in stock. About $89. Bought and installed it even though it looked very suspiciously like the first generic pump I had bought but with Delphi lightly printed on the side. Borrowed a decent fuel gauge and test drove with the hose snaked out under the engine cover so I could see it while driving. Did OK for about 10 miles then power started dropping off, along with fuel pressure. Swapped inline pump on but it split an o-ring, gushed some fuel, and I had to swap the filter back on and pretend like that puddle in the parking lot was there when I got there to a passing homeless guy. He wasn't impressed. Tossing funky old coveralls into a luggage compartment way back when was a really good move. Limped back home again. Faulty pump? More rust? Big positive that I did make it home though, up hills even. Class A tows are pricy even from a buddy.
9. Tank back down. Still some rust but not enough in the filter to really plug it this time. Cleaned it anyway and tank back up again. Borrowed fuel gauge again for a test drive with it. Didn't even make it out of the drive. Fuel pressure dropped off so bad I barely got it parked again. No more limping, this was failure mode.
10. Looking for wiring so I could test for voltage drop, like I should have already done but have no excuse at all for not doing. I soon saw some "green death" on the back of the fuel pump relay. Well I'll be a .... One connector on the back of the relay socket was so corroded it snapped off in my fingers. Cut all the wiring right off, crimped new terminals, and used a new Bosch relay. Ordered an ammeter to put on the dash so I could actively look for voltage drop.
11. Bought a decent fuel pressure gauge that won't leak. (Mac tools) Attached to the fuel rail and left it there. Ammeter came in. Meant more for a solar setup it also reads volts and watts. It came with a shunt. Part of my issue was I wanted to measure the power close to the pump and that was 30 feet away from me driving. The leads of my Vantage Pro aren't quite that long.
This thing came with a shunt and I installed that as close to the pump as I could get. It plumbed into the ground side and the ground ran off into the harness somewhere. I said bump it and added a new ground right there into the frame rail. Made it lots easier to wire in the shunt and that way I only had to run a small wire back to the meter. Anyway, fired up and saw the pump had solid system voltage and was drawing 2.38 amps. Seemed kind of low. Fuel pressure was only around 35 psi too. Hmmm. Test drove around the block, literally, and fuel pressure under load would drop down to 10 psi. Went straight back home.
12. Bail. People on this forum and elsewhere say buy a new replacement complete Ford pump assembly for $400 or so and be done with it. Not real happy about that but bounced it off the wife. We have a family camping event coming up in a few weeks and she wants to be there. She said do what I had to and get big booty Judy ready for the road. Well, I had already found the pump on Rock Auto the night before. Put it in my "cart" but didn't actually buy it. It said there would be a two day delay or something which sort of raised my hackles. Not really sure what they meant and haven't seen that on Rock Auto before. Anyway I went back the next day to buy it and it was gone. They cleared my cart. Gone from the entire site. They no longer even listed it. Went on the hunt, no one listed it. Ebay, Lakeland Ford, no one that I could find online. Bright side was that I really didn't want to spend that much anyway.
13. In between times, the rust in the tank bothered me. I managed to get a lot out with a pocket magnet as big flakes of rust are still somewhat magnetic. Gas fumes were awful draped over the tank though, I could feel brain cells dying. Got a better idea. I've had a big old speaker magnet from a dead speaker for years. I put it down in the tank bottom. Hopefully it will grab and hold some rust.
14. Got to do something to get this thing going so I hunted some more online. I've had good luck with Walbros as a brand. Guys in EFI Mustangs use them because they have upgraded capacity to feed hot rodded engines. Looked for one of those. Found a place in Florida. The pictures on their website showed a couple of harnesses do it would fit a couple of applications. The pump itself LOOKED like what I needed. It was listed as fitting an F53 but if you've read all this you know I've been burned by that one. Crossed my fingers and and tossed out about $150 (some extra for speedy shipping). One reason for buying out of a place in Florida is that I have ordered things from that area before and it's basically a 500 mile straight shot north to here so things arrive fairly promptly. They shipped. Went straight 500 miles past here north to Indianapolis according to tracking. I started to worry about my blood pressure. But somehow it made it another 500 miles back here and did indeed arrive on the second day I paid for. Yay, hotrod parts!
15. Installed the pump. Not a Walbro as advertised but an "A1" or something. Nice "made in USA" stamp on the side of it though and it's still supposed to be the uprated 255 lph unit so I went with it. Specifically a "TCA900HP High Performance Fuel Pump Kit" is what they call it at fuel-pumps.net.
Gave up on what they had for the quick and easy plug-in though. The adapter plug-in was there but incompatible with what they had apparently glued to the pump. Reluctant to try and pry that off and possibly damage the pump I just clipped the wires and used crimp style butt connectors so it then plugged neatly into my unmolested factory harness. Tank back up, umpteenth time. Key on about three times and the psi was right on 40. Fired up and it stayed there. Put it in gear and gassed it against the brakes. Pressure spiked up to like 120 psi and blew the return line off at the tank. Son of a.....
16. Tank back down. Replaced the plastic clips on the lines with the new ones I should have changed out in the first place that came with the pump. One wouldn't fit and I had to go get another properly sized one. While wrestling with all that I pulled back the plastic covering over the lines some and noticed that as-is the fuel line was almost crimped. Simple enough to make sure it had a straight shot by rotating the entire pump assembly in the bolt pattern. Previous owner probably put it back in wrong and I had been putting it back in the same way the entire time. Doh! Be nice if it was the return that looked almost kinked, would have made a good explanation for the pressure spike.
17. Test drive 5? 6?....I lost count. Pressure goes up to 42 under high load and idles at about 35 psi. Voltage normal and this pump draws 5.32 amps, almost double what the Delphi pump did and more in line with what I would expect from such a pump design. Drives like a big gawky and somewhat underpowered truck. Success! Then going over a dip the fuel gauge dropped from half a tank to 1/8 and stayed there. I semi-freaked, having visions of another popped fuel line spewing all over. Still running fine though. There was a gas station right handy and I zoomed in. But saw no fuel dripping or gushing. Not trusting anything and hoping to get back home I put ten gallons in and ran for it. About halfway home and observing that the fuel gauge did not move at all where usually there was a bit of sway I twigged to what the problem was. I had rotated the fuel pump assembly around. When the fuel sloshed down the fuel level arm came down on top of the big speaker magnet and bigod stayed there. Son of a ....
18. Dropped the tank again. Bless this motorcycle jack, I swear. Pulled the magnet out. Cleaned the rust particles off of it and figured since it appeared to be having a good effect I put it back in instead of overhanding it into the woods. Positioned well away from the sending unit. It did look like there was less rust floating around in there. Fired the coach to make sure I hadn't borked anything else and it seemed OK.
19. Now. Three weeks until camping trip. All seems good but I still have no clue what caused that nasty pressure spike that one single time. Even though it's kind of heavy I'm thinking of taking the motorcycle jack and other related tools with me camping. I've got the drop and raise a 70 gallon fuel tank bit down pretty pat. Still need to rebuild the fitting on my backup frame rail pump though. Readying a car dolly and plan to drag a toad around a bit for my final test drive before we leave. Four hour drive so not a really
big deal I guess.