Took a small road trip in my Decommissioned ambulance to Pittsburgh and back (around 650mi round trip) and had a little trouble about 100 miles from home. It's a 1991 Ford E350 w/ the 7.3l IDI diesel engine. Has 70k miles. So I burned the first tank down to almost E then switch to the rear tank, burned that one down to almost 1/2 when I noticed a significant loss of power. The engine was surging going down the highway. When I let off the gas it would pull for a second then coast, pull for a second then coast. When I floored it it was very sluggish and was having a hard time climbing hills. Actually broke down on the side of the highway. Could'nt get it to start. I went and put 5 gallons into the first tank and managed to start it back with a little ether lots of cranking and by pressing the schrader valve at the fuel filter housing to bleed air. She's been running fine off the first tank ever since. This makes me think I either have a hole in the pickup line for that second tank or the switch could be faulty? Switching maybe only halfway so pulling from both tanks until it gets air in the pump? Anyone have any ideas? Planning to fill the first tank then switch to the rear. Guess that would tell me if there's a hole in the line in the second tank if it surges and dies again..Maybe someone who reads this has experienced this and any info is appreciated.

 

The pickup tube in the tank probably broke off, its a common problem with these trucks. I'm not sure if the tanks in an ambulance are any different, but it sure looks like you'll either have to drop the tank to fix it, or just remember to not let the rear tank get that low and live with it.

Also, don't use ether if the glow plugs are working (unless you disable the glow plugs) Next time you run out like that, drop the fuel filter, refill it, then try to get it going, will hopefully start a bit faster.

 

Sonny. Glad to hear your rescued an IDI Van. They are the best. I specialize in the van part of the IDI, since there wasn't much on the net for resources. I'll use a bunch of links from my site to help explain my thoughts, and you can find lots more info there.

The "cone of failure" has broken off from your fuel pickup, and it won't reach the last 1/4 tank. You can see the old and new fuel pickups in this image below. the new one has the cone, and the old one is broken off.



One solution is to just run the vehicle with always a half tank of fuel. But if you wanted to fix yours up, it's simple. Just put a section of fuel hose on the end of the straw, and cut a notch out of the bottom of the tube.

I have two tutorials for replacing the fuel pickup (and the differences in the IDI van and IDI truck fuel level senders) here: Center Van Tank: https://www.nickpisca.com/diesel/fue...r-replacement/ Rear Van Tank: https://www.nickpisca.com/diesel/fue...ment-tutorial/

If your van is always sluggish, that is just the nature of the non-turbo IDI engine. Up the hills, it usually maxes out at 45-50mph. It's not very fast, but it's always going to get you there. If you want to bump up your IDI power, getting a van turbo would be fun: https://www.nickpisca.com/diesel/tur...ord-clubwagon/

You are really lucky you didn't have to bleed the injector lines. Whenever you get air in the IP or injector lines, you usually have to crack the lines and purge the air in addition to the air at the schrader valve. Lucky for you, it didn't come to that. https://www.nickpisca.com/diesel/fue...diesel-engine/

From my experience, I don't think the fuel selector valve (FSV) is air tight. So if you have air coming in from one tank, even though you are switched to the other, I think it causes some air intrusion. It's always best to make sure you have some fuel in both tanks, just in case.

You can find

 

pieces of broken pickup often end up in the Tank select Valve and can often cause Headaches


BTW nothing like the fun of a Shop Rag in the tank either ... Yeah I've seen it

 

 

WHAT!

There's no way the lift pump, much less the IP could pass a shop rag. I don't even think the engine in an M35 2 1/2 could pass it.

 

Because it does it around half a tank I think it's more than likely a pin hole in the pickup tube

The trick for the showerhead if you don't want to buy one is to build a bowl around the hose you use to extend it with aluminum window screen, that was my rememdy after those little pieces clogged my sending unit tube. It was a pita to get them all out. Luckily the selector valve survived

 

yeah there is often Filter screens in the pickup and return tubes but not always.

there is also check valves on return and on the shower head .....

 

I'm willing to bet his fuel senders are worn down and aren't reading the proper fuel level on the van. It was really bad on my van and I could never really know if I had a 1/2 or 1/4 tank left because the gauge was never right.

 

my 93 is like this the Gauge reads all over the place depending on the level in the tank so you never really how much is actually there... I know both my senders need replacement or at least need some out of tank TLC

 

Never tried this on a fuel sender but one really handy trick I learned for contacts in electronics such as ram sticks, CPUs that don't have pins ect is a cheap ol pencil eraser. Cleans em right up with minimal pressure!

 

ya we used erasers for years on switch gear and in old Teletype machines... you couldn't work on a Flexowriter without one

and yeah handy on edge connectors, but nowadays it is considered Taboo and you will be beat very severely if you attempt this.
IF you mention it at Stack Exchange they will Ban you

The Key to using the pencil eraser is Common sense which isn't so common anymore.... today's erasers are often made from different materials than we had years ago and can cause static damage to today's sensitive PCB not to mention the gold plating is so thin if you look at it hard you will scrape it off...

but Triboelectric Effect is very real today....





and I still use Erasers for many things and a Gas Tank Sender is probably a fine place for it

 

I use the little ones that slide over the end of a pencil. There still really soft and I've gotten fairly aggressive with some vintage ram I had and it didn't take the gold off.

I'll keep in mind to avoid any other type of erasers

 

I still have a bunch of the old eraser pencils with the Brush on one end made by Koh-I-Noor early 60's still in good shape after all these years too, I'm surprised they ain't all dried out.

Deoxit Products are my Go To


But of course being inside a tank and covered with diesel contacts you would think are self cleaning

 

Thanks for the info...OK so I switched over to the secondary tank that I initially broke down on at 1/2 after driving 100 miles on the primary tank that I filled to get it running again and it was pretty much EMPTY! This suggests that the valve that switches pickup tubes must be stuck in a position where it's pulling from both tanks at once. Now that both tanks are full I will switch tanks at 3/4 and if the other tank is at 3/4 this is 100% the problem.