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'91 Econoline 150, Fuel Pressure goes low

Here’s an update: I removed the reservoir/selector valve assembly. I tested to see if any fuel gets pumped out the feed lines from both tanks - not even a drop. I got the tank lowered onto the floor but haven’t yet disconnected what appears to be a vent hose close to where the fuel lines and electrical connector go. I decided to spend the next few hours looking for information on this hose and also information on where to get an o-ring for the reservoir. I haven’t yet found info about the hose, but I did find a website that gives a lot of information about the reservoir/selector valve assembly. According to this site, if the reservoir says “DO NOT REMOVE CUP”, then the reservoir does not contain a filter. The reservoir on this van must not have a filter then. The site also tells how to get a filter and o-ring, which according to this site, I won’t be needing. This is the site here: https://www.supermotors.net/registry/media/673878 There are 34 pages of info for this reservoir.

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Thanks for the update. Many of us here appreciate this kind of information.

I got the tank out yesterday and confirmed the in-tank pump doesn’t work. It took me a while to figure out how to get the vent hose out of the top of the tank. I grabbed hold of the vent valve and worked it out of the tank along with the rubber grommet, being careful not to break the plastic. The tank on the inside has no rust, but I rinsed it out really well with a water hose to get rid of the gas fumes. I didn’t want a fire hazard while waiting for parts. I got the new pump today and have it installed on the pump/sending unit assembly. It took me a while to figure out how to remove the filter from the bottom of the pump without destroying something. The instructions said “remove the filter” but didn’t tell how. There’s no picture of what the pump connection looked like and couldn’t find any picture of it on the internet. I found two or three videos on youtube of someone changing the pump, but they changed the whole assembly. I did find a few videos of removing the filter but it was different design, so not helpful. What I did was pry between the mounting and the rubber washer to get a look at what the filter connection looks like and then slowly pried the filter off with the screw driver. The filter has a tin cylinder piece that slides tightly over the plastic cylinder shaped piece on the end of the pump. I’m wondering if I should replace the in-tank filter because it’s clean and not at all deteriorated. The fuel tank had no sediment or anything in it. Tomorrow I’ll talk to the owner and see what he thinks about buying a new filter. I was planning to buy one today but I forgot to mention it when I ordered the pump. I’ve heard that the filter should always be replaced when changing the pump and I agree because it’s not easy to get in there. What do you think, should I change it?

When you say in-tank filter, do you mean the “sock” . . . ?

If that’s what you mean, definitely replace it

Yes, that is the standard practice

Yes, I mean the sock. I talked to owner about it last night and he agrees to change it, so I’ll be looking for a new one today.

The van is now repaired. The problem was the in-tank pump.
For anyone who might be reading this thread in the future for help on something similar, I’d like to add something that will open me up for criticism. If it does, then so be it. Hopefully those with experience will add to it. This is my first time to work on a Ford and the first time working on a fuel system, so I went through a learning curve on this system. I did a lot of research on the internet, watching videos and reading articles, and I borrowed books from the library before making this post in this forum. I made a mistake when working on this van. I read and heard that when pinching off fuel lines during the testing, never pinch off a steel line (for me that’s obvious) or a nylon line (for me that’s also obvious). Only pinch off a rubber line. When I was putting the fuel lines back onto the fuel reservoir, one of the lines didn’t want to go on all the way. As I was trying to force the fuel line on, it bent (put a kink in the nylon line). As that happened, I was looking at the rubber tubing around the nylon line and I suddenly realized the lines I pinched off with vice grips by the engine are actually nylon lines inside rubber tubing. I felt really stupid for the rest of the day and was really mad and kicking myself and don’t blame any of you for thinking or calling me exactly that (stupid). I hate it when I have to learn the hard way. I straightened out the kinks with pliers and there are no leaks, but those spots are now weak spots. I’m lucky the lines didn’t crack. They aren’t leaking but they are weaker in those spots. There aren’t any places on these lines that can be pinched off. If I work on such a system again, I’ll have to figure out a way of restricting flow in both the feed line and return line when I’m testing the system.
I figured out how to get the nylon line onto the reservoir. First of all, hold the line right at the connector. Holding it a few inches away from the connector where it’s easier to get a grip can cause the line to bend if there’s some resistance, as what happened to me. The line wouldn’t go on all the way if I tried pushing it straight on, but if I turned the connector back and forth, clockwise and counter clockwise, while pushing it in, then it went in.
I used a small flathead screwdriver to clean the dirt out of the connectors and then used a Qtip to spread engine oil inside, making sure to soak the o-rings. I read and heard that the only lubricant to be used on the fuel line is engine oil. The o-rings all looked good, but I wasn’t sure if they would seal. So far they aren’t leaking. I saw some articles that said never to replace the o-rings but replace the entire length of fuel line. Other people said to just replace the o-rings. I’d like to hear opinions about that from those with experience.
Thanks for your help.

Good info, thanks for posting. Glad you got the E150 back on the road. I was under the impression the problem occurred w/either of the tanks. Have you resolved why the other tank isn’t working? Or is the owner satisfied just having one tank working? For local driving, one working tank is plenty. Those fuel tank selector valves are a little pricey, glad it wasn’t that too.

I haven’t checked the problem with the other tank. The owner only wants the one tank working. The van is used for construction and only used as an emergency vehicle when his main vehicle has a problem. It will remain parked most the time. The previous owner didn’t say why they stopped using the rear tank. When I had the external pump disconnected, I wasn’t able to hear any pump noise at all. I put some fuel in the rear tank and the engine stalled exactly the same with either tank selected. There’s probably a lot of varnish build up in the rear tank as well as a result of not being used for 20 years. We can only assume the pump isn’t working in the rear tank.

All the information about the install will be helpful to someone else, and it’s one of the great benefits of the internet that we now have access to each other’s screw-ups as well as victories.

When I do a job that requires a big tear-down to get in I tend to replace everything I can reasonably do at the same time. I don’t pay me for my labor, but doing the same difficult job twice really makes me unhappy.

I don’t know precisely what materials are used in the fuel lines you are reinstalling, but in general I find heating up the end of the hoses with a hair dryer or a heat gun on low tends to soften them up a bit and makes the job go more smoothly.

On this van can you route the fuel line around the selector valve, so that whole second tank system is abandoned? It might avoid issues later.