Not sure where best to post this so feel free to move.

We're pretty sure it's time to change out the fuel pump on our van. We have no opposition to doing the work ourselves but being on the road full-time and living in the van has us limited on the following:

1) No place to comfortably park and do the work / spend the night.
2) Tool necessary to remove fuel pump (think we can rent that at Oreilly's) and socket for straps (borrowed last time)
3) Last time we dropped the tank it took three of us and a motorcycle lift to lower it.
4) No place to drain fuel to or neccessary items to facilitate drainage

Details:
About six months ago van started sucking air / sagging /lagging on hills or steep grades once it got to ¼ tank left. We solved problem by always filling up before we got that low.
Yesterday, at just above ½ tank it started same behavior while traveling from CO to WY and taking in moderate grades… no problems on flat. We solved it by filling up asap and have been filling up at ¼ tank down last few times.
Obviously, we don’t want to go another six months (if we got that) filling up at only ¼ tank down.
We’re pretty sure it is a fuel pump / sending unit issue as there are not other signs / symptoms and the change when going up a grade is consistent based on level of fuel.
Could it be anything else?
When tooling down the highway or around town she runs like a champ, doesn’t rough idle or act like stalling out or anything.

Long story short. We are not only independent and capable but we are also full-time vandwellers now. We would love to have the opportunity to do the work ourselves and of course to save money in the process.
Is there a vanner out there in our area (Laramie) who has the room and tools and know-how to give us assistance with this project??
Please email nicolespamcan(at)gmail(dot)com if you think you can help with the work because we’ll get it faster than here.
Thanks!

Niko, since your pump is in the tank what I'm going to suggest you check before tearing things apart is not the most likely culprit, but if it pans out this idea would sure be more pleasant than dropping a tank...

Have you changed any in-line fuel filter(s)? Sometimes people have installed more than one in line between the tank and the engine. If they get filled up with water or are clogged you'll experience fuel starvation symptoms. A lot of times going up or down hills aggravates the situation.

It sounds like you may spend significant amounts of time parked. It's more likely that your tank will experience significant amounts of condensation inside when it's only partially full. If it's an option for you, it would be best to keep your tank relatively full when parked. The less air inside, the less moisture can condense out.

Thanks. Good thoughts. Although we do stay parked for a week or so at a stretch, we almost always fill up before hand (just to ensure we're good in an emergency). Since having the problem six months ago we have also made a point to not let it drop less than 1/2 tank.

The first consistent culprit is that it only happens going up hills or steep grades. It does not happen at all just driving on flat surfaces.

Second consistency is that it is directly related to the amount of fuel in the tank. For six months we coudln't go 3/4 down or it would happen. Yesterday it started at between 1/4 and 1/2 down. We filled up and no more problems.

We were thinking pump was overheating when it was happening at 3/4 down but now it's got us confused.

No inline (added) filters by the way, just the primary which I changed not long ago. Figured that happening on only steep grades wouldn't be the issue with a filter as thought they were consistent in their affects.

I'm glad you changed the filter, that was a great move.

A water-logged filter is often grade-sensitive; if there's lots of water in a filter, it will flow towards the low side while driving on a grade, which at least in the case of horizontally-oriented in-line filters does interfere with fuel flow; I've had it stop me dead going up hills. I've been more careful since then, and try to get filters which are clear enough that I can see into them. I also run dry gas through once in a while.

If a fuel line has a substantial low spot in it, water can pool there too. This is what often gets folks in cold climates when it freezes. I gather freezing is not much of a concern for you!

Do you suppose there might be a bunch of water or sludge in your tank?

My next guess for the most simple things to check would be the fuel filler cap. If it's vents malfunction you'll draw a vacuum, which will starve your engine of fuel. I'm not sure how that could be grade sensitive, but it's really simple to try. Just gently open the filler cap after experiencing the issue and if you hear a whooshing sound from air rushing in, a vacuum had developed in your tank.

When you had the fuel pump changed last time, do you suppose that there might have been a hole punched in the pickup tube? That would allow air to be sucked in. I've heard of corrosion making pinholes in pickup tubes too.

Thanks for your responses.

I should clarify a few things.

I've probably mentioned the fuel pump being bad. What I mean to talk abuot is the 'pickup tube'?? Or whatever it would be called if you don't have an in-tank pump.

I have a mechanical pump.

On that note... someone had mentioned that tube could break off due to age?? If so, that could explain the change in fuel level i need in the tank to keep it from starving on hills?

I get what you are saying about the water in the fuel and filter and how it can change even in the filter with grade. Will be good if it turns out that simple :o) My filter, by the way, sits upright long ways.

We've been searching like crazy for pickup tube online but can't find one. In FSM it's called fuel gauge sending unit and has a float (even for vans with mechanical pumps).

Arg...

Almost wish I still lived in Laramie, you could park in my drive for days if needed, but alas I do not. BUT, on the NORTH side of town, there is a camp ground, they used to allow vans, school buses, ect to rent there. . . good luck!

It is behind the Pilot truck stop, and they have free wifi too, in the office area.

Thanks for the info. We're actually just biding our time until our campground volunteer job starts in a few weeks. We may choose to fix it there if 1) we can figure out what needs fixing and get the parts 2) figure out a way to drain the gas since we can't go below 3/4 of a tank 3) make it to our job as it requires another 1200 foot elevation gain ;o)

Okay, just a thought, but are you sure your float is not sticking? It could be sticking just enought to let you run when flat, but flood when on a tilt/ incline,......you can test this fairly easy, put a can of sea foam in the tank and run it out....this will clean out any gummy junk that might be sticking the float.

Remember, on a carved system, there are few parts, carb, filter, pump, lines, tank, and the fuel level float/ pick up tube. Start easy/cheap and go from there.

You replaced the inline filter, what about the brass one in the carb? Right where the fuel line threads into the carb. Careful, these threads are fine and delicate.

NIKO on my 90 there is a rubber line By the back axle that is for siphoning the gas tank. If yours has it there will be a plug on the end.

Fester... No, not sure the float isn't sticking. That actually had crossed our minds. and, yes, we are looking for the easiest (and cheapest) available.

Dr. Bob... Our FSM says that plug is only on 3.9 or 5.2. I'll still take a peek when I get a chance just in case. Thanks.