The Summer of Ven: IDI Fuel System Teardown and Electric Fuel Pump Retro-mod

This series of posts will detail the first major system modification I perform to the IDI 6.9 liter engine of Spool Bus, inspired by the work of other enthusiasts like Nick Pisca.

After finishing the brake system work and getting it driving well, I noticed that it suffered from a pretty badly aerating fuel system. As I mentioned in the Murdervan post, the IDI engine family depends on a fuel system that is fully primed and free of air, or they tend to have severe starting issues. Coupled with a mechanical fuel pump that’s crankshaft driven, and it means a lot of work is dropped upon the starter (and therefore batteries and heavy power wiring) to turn over and keep cranking an all-original engine with dried or cracked rubber hoses to pressurize the system. Spool Bus definitely exhibited this problem along with a non-functional glow plug circuit, making things even worse.

To make up for it, I would do the unspeakable thing and feed it a tiny puff of ether (starting fluid) if cold starting. It would always getup and go immediately, which indicated to me there wasn’t really anything wrong besides the aerating fuel lines. With fall and winter on the horizon, I decided to go for the mod both as a quality of life improvement and because the system needed addressing anyway.

The changes entail removing much of the OEM fuel delivery system and replacing it with an electric low-pressure pump to feed the high-pressure injection pump unit, as well as relocation of the fuel filter mount from its basically-impossible-to-service OEM location under the engine cave ceiling.

See, a lot of these parts would be perfectly reasonable from a service perspective with overhead access in the pickup truck line. But when you shove all of it 2 feet backwards with the engine squarely under the dashboard, those OEM locations just make you go what. how. WHY. I keep saying Ford (and other manufacturers!) should have just committed and kept the van line cab-over, but I say that as a die-hard defender of the Church of the Cab-Over Van.

So here we go! Part 1 will focus on deconstructing the original fuel system, basically acting as a pictorial guide if you might ever want to fix one. Next will be the installation of the new electric fuel pump, and then I’ll clean and wrap up everything with new glow plugs and return lines.

Up in the “Service Position” it goes! I promise, this is far less sketch than it looks, as for some reason the slope of the driveway is exaggerated by the framing of the picture. That’s also what wheel chocks are for. The previous renter of this place left these big cut up railroad ties that worked suspiciously well as ramps, so maybe we had the same idea!

We’ll start with the underbody inspection. So, Spool Bus has no less than three fuel filters. I think people just added more fuel filters as they got clogged or something, not gathering that’s not how it works. I’d been getting some fuel feed problems before this where it feels like it’s running out or pulling air, losing some power while cruising. Having experienced this in Mikuvan back in the old’ dirty gas disaster days, I figured this was another impetus to finally making the mods, which is basically another chance to dig through what previous owners had done. The state of service of a van always tells a story, often a tragedy.

The item shown above and to the right of the yellow (new!) from shock absorber is the OEM fuel-water separator fitment. I figured it was OEM, as it was located in a spot that only Ford could have installed BEFORE they put the van part of the van on the van.

Next, moving just a few feet back, on the frame was another fuel-water separator unit. This is plumbed in right before the fuel tank selection valve, just inboard of the frame rail from it.

….and I know it’s hard to see exactly what I mean, but the white object immediately behind the A/C compressor shown at the bottom is the OEM fuel filter and its mounting fitting. Yes, far as I can tell, to remove this thing and replace it you have to actually unbolt the A/C compressor.

I always felt like the van line of any car company got the most disposability treatment. I mean, why not? They’re generally the most vocational of the product line. Buy them for your contractor, plumbing, environmental disaster response, etc. fleet, run them for 50,000-70,000 miles, and then throw them away before anything becomes a problem.

So the OEM water separator has a little cable coming out of it that leads to this knob under the driver’s seat. You pull it to pull up on a plunger inside, and theoretically with water being heavier than oil, all the water collected at the bottom will drain out. Pull the plunger too long and you drain out your fuel system as well ¯\_(ツ)_/¯

I decided to dismount and mess with all the filters to see if they were exceptionally clogged or something to cause the fuel feed issue. I mean, the answer was Probably Yes, but I wanted to be thorough and see it firsthand anyway.

I yanked off the frame-mounted filter and… eww. It was chunky inside from an uncertain source of brown. I read that algae and other simple life forms can begin growing in situations where oil and water sit together too long. Whatever, I don’t care. Obviously, we needed a replacement here.

With a bit of hose following, I found out that the OEM water separator was actually no longer in the picture. I might uninstall it one of these days, but not right now.

To uninstall the OEM filter, I had to remove the intake hose and luckily was able to sneak a strap wrench in there just enough to start breaking it loose. There was just barely enough vertical volume to wiggle it out afterwards!

So here we have the two “Original-to-me” filters. I decided that the existing frame-mounted filter head was fine and dandy for anything I wanted to do – no use to purchase a new one, even if it’ll be fancy. I’d mount the electric fuel pump right next to it on the frame, and just run a hose straight from there to the engine.

There does need to be an air purge method located at the highest point of the fuel system. For that I brewed up a plan to use an electric solenoid valve connecting that point to the fuel return system, and so I can activate the P U R G E from inside if need be, instead of having a manual fitting like the Schrader valve on the OEM filter head.

Time to start deconstructing from the back side in order to remove the rest of the fuel system. Remember, this bullshit is what I’m dealing with. There is a LOT going on inside the engine cave of the Ford van chassis, even without Dashboard Turbo giving me the side-eye here like he owns the place. Nick’s assertion that the most valuable real estate on a van is under the hood and inside the engine cave is absolutely correct – whatever I can remove from here is added service access and airflow.

First to go is this torn up plastic coated metal coil intake hose. So it’s just been pulling air from wherever the hell it felt like all this time, huh? I’ll order a proper new one when I get to that point.

This is the view from the driver’s side of the engine cave, out towards the front. On the left, the shiny cylinder is the rear of the A/C compressor. To the right of that is the OEM filter head location, and to the immediate right, the black casing is the turbo compressor’s outlet adapter to the intake.

That’s right, there is NO blow-off valve or intercooler here. Just straight in…. as well as straight out. There’s no wastegate attached to the turbo either. It’s just “sized right” and with a 1000 pound blob of cast iron underneath it.

The view going the other direction, peeking in just under the hood apron. At the end of this adventure, the metal tower that is the OEM filter mount will be gone.

I’ve got a bunch of other hoses removed now, and also have removed the crankcase pressure regulator (the can at the bottom), which I’m led to believe works like a very overgrown PCV valve. This was enough volume for me to get a read on where to route and mount everything.

Fast forward a few days, and a combination of Papa Bezos and RockAuto have #delivered. I also just took the old filter to an O’Reilly and held it up to them and went ? ? ?, picking up a combined filter and water separator (that little knob at the bottom loosens to drain and also cover you in diesel-water poop)

Also in the order is the electric pump itself. I went for the near universally recommended one, a Facet DuraLift unit, and also ordered a bunch of brass fittings to match.

I also picked up a “fuel pump block-off plate”, seen in the middle of the fuel hose coil. I obviously didn’t know this, but it seems like every mechanical fuel pump for decades was the same hole pattern in the side of the engine, so there’s like only 2 products that cover up the hole for every American vehicle ever.

Step one of this whole disaster: Remove the mechanical crankshaft-driven fuel pump. Apparently the diaphragms inside these pumps can eventually (or prematurely) fail, which then dumps fuel into the crankcase. Great!

This photo makes it look like a reasonable service position. It is in fact not. I’m looking upward from just inside of the front passenger side wheelwell. The structure at the left is the engine cradle/crossmember. The orange b u l g e is an aftermarket coolant filter some previous owner installed (hmm, this is a good idea in general) which was absent on Murdervan and made this whole adventure that much harder to navigate.

Of course you can’t see the bolts either. If you ever want to work on vans of any sort, you have to be really comfortable with “Braille Servicing” out of sight and only having your proprioception and tactile feedback to let you know if you landed the socket or started the thread.

Face Down, Ass Up, That’s the Way We Like to [adjust the power steering belt tension on a 1975-1991 Ford Econoline]

I got a start on it with removing the fuel feeder line coming from the switchover valve (rubber, bottom nipple) and unscrewing the rigid line going to the OEM filter head (flare nut, upper fitting). The bolts holding the pump on are standard 3/8″ with 9/16″ wide heads.

I went ahead and pulled up the rigid line from the front of the hood after undoing a few clamps holding it to the engine.

The rigid line has a heater element attached to it that’s powered from a fusible link system coming from the passenger-side (primary) battery. I have no particular use for this, but will be tapping the power for the fuel pump later.

To remove the fuel pump, I actually found it easy enough to use a standard box end wrench. I didn’t have a ratcheting-end box wrench or a socket that would actually fit in these confines, so I just suffered through it with the initial loosen, and then the removal by hand was easy enough.

And here it is dumped out the bottom. Installation of the block-off plate was far more pleasant, as there was now nothing in the way.

Next up is to remove the OEM filter head and its fittings, also easy enough with a 9/16″ ratcher, though the approach angle is better from the front-right position (shown here).

Here we have the pile of scrap generated from this evening’s operation. Well, I suppose the intake pipe adapter isn’t scrap, but it happened to be laying here as well. Some of these rigid tubes will be harvested for their fittings and make it back into the operation.

Next up, re-plumbing the engine fuel feed and adding the electric lift pump!

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