Afternoon all,

I have a 1990 E250 cargo van with dual tanks. I get the rear tank fuel pump energizing at key switch on. When I switch to the fron tank, no fuel pump noise at all coming from the front tank. I removed the selector switch and with continuity checks, it checks out fine. I am going to make sure I am getting signal to the pump from the selector switch tonight to make suer the wiring is good. i suppose grounds could be checked as well. After this all checks good hopefully, the only thing left is the pump. Questions:

i was reading the Ford electrical and vacuum manual last night and they speak of a fuel booster pump. What is that? That is not that big valve can mountde on the frame is it? I thought that was a mechanical valve that just routed the fuel from either tank to the fuel rail. Could this fuel booster be the problem why my front tank is not working or if it was neither tank would work? Right now, the only tank that works is the rear. Is there any maintenance or cleaning that I can do to the mechanical valve? Where can I get a selector switch just in case as an extra?

thanks

Sid

 

i believe your truck had low-pressure pumps in each tank, then a high pressure pump mounted on the frame, just forward of the tank selector valve. the tank selector valve has 6 ports, of which 2 go forward (supply and return), and 2 go back to each tank. following the fuel line forward of there, you find the "big valve can mounted on the frame" as you described it, this would be your high pressure pump. the fact that you can run on the rear tank tells me that your rear in-tank pump is fine, and this high pressure pump is fine, but your front tank pump is dead. if there isn't an obvious wiring problem, you need a pump. in my opinion, if you drop the tank only to find that a wire inside is damaged, you've already done all the work of a new pump, and may as well install a new one. dropping gas tanks is never fun, especially the second time

if you can reach the wiring connector to the tank without dropping the tank, connect a 9v battery to the wires that should run the pump. that'll be your final confirmation that the pump itself is the problem before you open it up.

 

Thank you very much for the reply. I am in the process of putting in a new floor. So all of the tanks, pumps, wiring and hoses are all exposed and right there for mne. I figured I'd fix them now while I can get to them. Are saying a little ole square 9 volt transistor radio battery?

Thanks

Sid

 

A high pressure fuel pump for the fuel injectors.
No it is not.
That is what it does but when fuel leaves it, it goes to the high pressure pump and the fuel filter before going to the fuel rail.
Yes if it was not working neither tank would work.
You can take the cup off the bottom and clean it out but you will have to replace the big "O" ring if you do.
Auto part store.







/

 

yes, i'm saying the little 9v batteries you use in the smoke alarm, battery backup for all kinds of things, yeah those. they have enough power to test your pump, light bulbs, relays, all kinds of stuff. they even make an adapter to use them to hold your car's computer memory while changing batteries on cars that lose critical memory when power is interrupted.
i like them because i don't have enough power to smoke anything, but still have enough power to test things

 

Evening guys,

Well as you can see by the front tank pump plug in the attached pics, there seems to be some sort of yellow gel on the pump contacts as well as inside the plug that goes to those contacts. I do not know if that is some sort of factory installed grease or insulate to shield the contacts from water or if it is gelled up old gas finding its way back up to the plug/contacts interface. I'm thinking maybe the latter. Question is, how did it find its way up there? I disconnected the plug from the pump and put a good 9 volt battery to the red and black pins on the pump. No noise at all. I tried the red and the other black pin. Still nothing. The schematic shows the red to be power to the motor and either black to be ground. The yellow and blue I think it was was the signal from the sending unit. Regardless, neither black and the red gave me a noise or any hint of life. I'm guessing to prove the pump good at this point, I should have heard something. No?
Last question, Advance Auto has several different pump manufacturers. From Bosch, to Nippon-Denso to Airtrex to a couple others. Any tips on a descent choice? They all seem to be somewhat in the same neighborhood as far as cost goes. Anything in particular I need to pay attention to upon installing the pump? I am still searching for a good deal on the Ford factory service manual set. I do have the Electrical and vacuum book but not the other two. I do have a Chiltons that I borrowed from the library though to hold me over.

Thanks again guys for all of your help.

Have a nice night.

Sid

Sorry, cannot post pics for some reason. DARN!

 

since the pump gave no sign of life, you just proved that your pump is indeed the problem.
as for brand, i've bought a number of airtex pumps for various cars and never had a problem. bosch and denso are also good names, though i lack direct experience with them.
as for installing the pump, its pretty straightforward, the only problem i've run into is the gasket slipping out of its groove. not long ago on a smaller ford, i had one that the locking ring was locked into all but 2 of its tabs, i thought good enough. well the first time she filled it full, it leaked like hell. came back and found the gasket had slipped out of its groove, causing a major leak when full. ever try taking out a fuel pump on a full tank? well i did, i made it work, but it wasn't fun.
other than that, just make sure it matches the old one and the locking ring gets in place easily, and you're good to go. the goo you found on the contacts in dielectric grease, used to prevent corrosion of the contacts. it seems that its hit-and-miss to decide whether or not the factory chose to use it on any given application.

 

Note that this has to be a new never used 9V battery and then it will just bearly run the pump with no load on the pump on the bench.
The pump draws 2 amps @ 12VDC running no load and will surge a lot higher than that at first with a bench power supply. The pump runs much faster with the bench power supply than the 9V battery.
I just did bench tests on this to check it all out.
The pump was out of a 1995 F-series truck.
The pump from an in-tank pump from an 89 draws 1 amp @12 VDC but runs about the same on the 9V battery.

 

Thanks guys.

Let you know how I make out. 1 more thing. What does it take to be able to post some pics for you all?

Sid

 

to post pics, see the how-to in the top of this forum. in short, put them on photobucket or another photo hosting site, then paste links to them into your post