89 F250 SuperCab 4x2 460 with FI and dual tanks 19 gal front and 18.2 gal rear.

Okay guys, the midship tank pump was dead. My truck has the 2 pump (3 actually I guess) system with pumps in the tanks and one on the frame. The rear tank pumps great, but the front tank was dead as could be.

I replaced the front tank pump this evening with an Airtex E2487 purchased from Advance. It's the only pump option available at AutoZone also. That's just the pump, not the entire assembly, for what it's worth.

The new pump works, but, it apparently doesn't pump sufficient flow. I can drive up to about 45-50mph on flat ground before feeling the engine start to starve for fuel. Anything more than 1/4 throttle at any speed will cause the engine to bog down. Full throttle is more like applying the brakes, lol.

The way the system works is that the high volume pumps in the tanks supply fuel through the tank selector switch to the high pressure pump on the frame. From there it goes through the fuel filter and on to the fuel rail.

When I switch to the rear tank, I get perfect performance, so I'm sure there's no problem with the high pressure pump or the fuel filter. But when I'm on the front tank, it bogs down like I described.

I'm 99% sure it has to be a defective pump, or that the pump simply wasn't designed to put out the amount of flow that big 460 needs. However, I have no idea how long the front pump's been bad. I wonder if the tank selector valve could be gummed up or partially restricted. I've never had a truck with dual tanks, so all this is a bit new to me.

I'm open to any suggestions or your experiences on the matter. Are the Airtex pumps just junk? I'd be surprised if they are with the volume of pumps they sell through Advance and AutoZone, but I suppose it's possible. Have any of you dealt with this problem before? Is it possible that the tank selector valve isn't opening all the way? I don't really know what type of valve is in there; it may not even be possible for it to open only half way.

Thanks in Advance, or in whatever store you're in.

 

I purchased a Bosch frame rail pump from Advance Auto and the engine would stall after letting it idle in the drive way for 15 minutes. They exchanged the pump.

You can test the questionable pump by doing the following.
First disable the frame rail pump by unplugging the electrical connector at the frame rail pump. You don't want the pump running with no fuel.

Disconnect the hose going to the input of the frame rail pump, Place the hose in a bucket. Ground the Tan/Light Green wire on the diagnostic test connector (Ford calls it the VIP connector) located on the driver side fender well. Turn the ignition on. The in tank pump should pump 16 oz or more of fuel in 10 seconds.

A picture of what the test connector looks like is in the top right of this schematic.



There have been people that had the valves in the reservoir not switch due to a valve jamming. It appears the design of the switching valves makes them impossible to fix.

A new selector valve is around $77.00 from ford. F1uz-9b263-b called a fuel system service kit.

If you can get enough slack in the four hoses on the back of the tank selector valve you can swap them around. The selector valve is mechanical and switches by the pressure from the in tank pumps. The larger diameter hose is the supply the smaller one is the return line. If you do this test you can determine if the in tank pump is bad or if the problem is in the selector valve.

 

That's excellent information. I think the quickest of the two tests you suggested would be to swap the hoses at the selector switch, if I can get the slack, like you said. If the front pump still bogs and the back still doesn't, it would have to be the new pump.

Thanks so much for the quick, thorough reply. In the mean time, I'm going to put some Seafoam in the tank just in case there's some cruddy stale fuel deposits in the works somewhere.

 

when ihave to switch to my rear tank i have to go under the hood and ground the self test connector and let the pumps run for a min or two or i have symptoms as u describe. I am just too lazy to change the valve.

 

So you're sure it's the valve? What would running both pumps do to the valve to make it run right? I'm not doubting you, just trying to picture it all.

Thanks

 

I am not real sure, from what i understand mine is either a bad seal or a sticky valve.But whenever i have to use my rear tank,if i dont do what i previously stated, it will not run very long before it starves. I actually found this out makin sure that my rear pump actually worked. So i unhooked the wiring to thefront pump and the line at the back of pump,and jumped the connector. After about a min of the pump running fuel started to flow. reconnected everything was great till i switched tanks,and then tried to switch back,after a brain fart and fillimg the wrong tank. It died out after about a mile. switched back to front,and drove home and jumped the self test. after about a min u could hear a big air bubble in the tank and was good to go. Cant really explain why this worked but it did.

 

Well, I'm beginning to think it is the valve. I haven't had the chance to test the valve in any way (my 3 y.o. daughter is in the hospital and my wife is having surgery in a few days).

The thing is, the more I drive it, the more flow I get from the front tank. When I first changed the pump, I couldn't give the truck more than 1/4 throttle, and struggled mightily to drive 60 on flat ground. Now, after 3 tanks and 3 cans of SeaFoam, I can give it at least 1/2 throttle and have no struggles keeping up on the interstate. The only stumbles are when I'm trying to accelerate rapidly from a stop or to pass on the interstate.

Not only that, but I've noticed that when I drain the front tank and switch to the back one, the back tank has been drained to about 7/8ths of a tank. I fill the back one 100% when I fill the front, but apparently some fuel is getting sucked out of the back tank when the valve is switched to the front. That would lead me to believe that the valve isn't moving fully to the right position.

Anyone who can confirm or destroy my logic? I'd really appreciate it before I spend $80 on a valve I don't need. Also, is there any chance that I could take the old valve off and clean it with throttle body cleaner?

 

am new user accidently posted other day on someones.anyway have 88f20 4x4 351 auto dual tanks.that selector is pressure operated always used front tank--run awhile then quit--after wasting lots of time put line in gas can pump gas okay--pump good(main)disconnected each tank hoses rear smelled like turpentine--so hooked fuel lines from front tank directly to front tank---no vavle runs good now. somehow siphoning fuel from back tank even though switch front tank---cheap fix for me--hope this helps you...........

 

I would say that the valves gone or it may just have some crud in it. Ive seen articles on tearing them apart and replacing the seals but?????? Google it maybe ull come up with something. Id sure give it a try before puttin out the money for a new one