90 F150 Engine dies when switched to front tank.
 

Hi,
Just bought a 90 F150 2WD (302 Fuel Inj) that has two fuel tanks & when I switch to the front tank the engine dies. Been searching this forum for a while & found post = https://www.ford-trucks.com/forums/1...nk-switch.html which has a great deal of info & seems to be pointing towards either a bad in-tank pump, dual function reservoir or a check valve in one of the fuel pumps (possibly bad gas too - don't know how long the gas has been in there). Have replaced the selector switch in the dash - no help.
Also found another post on another web-site, don't know if it's OK to mention another site here but found it interesting that subford was in both = http://www.fordf150.net/forums/viewtopic.php?t=70701.

Began to exihibit information overload & am somewhat of a novice when it comes to other than simple repairs but want to work on this truck myself. So before I tear into this gas tank can someone tel me if I'm heading in the right direction? Sounds like replacing the fuel tank selector valve would be an easy fix before dropping the tank? What is the FDM (Fuel Delivery Module-is that the pump?) & should I replace the check valve if the tank is removed?
Also is there a repository for F150 fixit stuff I can easily find that has repair instructions e.g. removing gas tank/replacing in-tank fuel pump. Guess I could get a Chilton's unless there's something better?

Your truck has the ITR pumps (in-tank reservoir) so you don't have that other stuff you were talking about. I'm betting it's your fuel pump that is bad - this is pretty common.

Thanks jas88,
Found a 1990 F150 Shop Manual (used) on Ebay for $93. Is the detail in the Shop Manuals what I'm hoping for? The Chilton's I've had for years doesn't go into a great deal of detail. See a lot of posters on this site that are hesistant to buy Shop Manuals because of the price. It seems to me if it makes the job easier the manual could pay for itself quickly?

Yeah the price is the reason I hesitate to buy tech manuals as well. My chilton manual tells me enough, and if it doesn't, I have FTE. :)

Which, by the way, welcome to FTE. And I second the bad fuel pump.

Also, good to see another "Gumby" floating around. My nickname in high school was Gumby. :)

Felt the tranny slip a couple days ago, AC doesn't work (not that important around the base of the Rocky Mtns), & of course the gas tank issue. Was hauling fence posts home from Lowes last week & became extreeeemly distressed when I scratched the tailgate on the Bronco. Bought this truck the next day. With a little time, $$ & TLC I'm sure this truck will be running great.
Be talking @ you guys soon.

Yea I also would say it was the fuel pump. I recently had the same problem on my '94 F150 with dual tanks, but the rear tank had problems. It turned out to be the fuel pump, but I changed out the fuel relay, and the 20 amp MAXI fuse, and then of course the fuel pump. Also when buying fuel pumps, I would suggest anything it originally came with. So like the Fuel Pumps should be Motorcraft, I replaced mine with Motorocraft. Delphi and Airtex I have heard good and bad about. Hope this kinda helped.

fuel trouble
 

Just a thought. Before you go taking every thing apart, it may be worth while to do some trouble shooting. Make sure you have power going to the pump, dont have a plugged line, (not that uncommon) blown fuse, ect ect. Im sure you may have already checked these things but, it really sucks when a person takes thing all apart, rebuilds and shat still dosnt flocken WORK! Changing fuel pumps is a bummer, especialy if it was an easy fix. Any way thought I would trough that out there. Best of luck to ya.

I agree with Stephenwightsfords. Perhaps that tank hasn't been used in years, hence the high gas prices. I agree about the bad fuel pump though. Also, as far as replacement pumps are concerned, I have replaced 3 original Motocrafts with Airtex pumps, and not one problem with either of them. That includes 2 front and one rear.

To check the fuel pump, short the Fuel pump lead of the DLC connector to a known good ground. Unfortuanely, I don't have a diagram for you. Perhaps someone else here can chime in with one. I belive Subford has one floating around on here. If you hear the pump whirring, could be a blocked fuel line.

Stephenwightsfords wrote: Im sure you may have already checked these things but:

No, I am a Gumby. That is why I joined this site, exactly for that kind of info, thanks. The easiest way to check would probably be to have someone turn the ignition key til the pump actuates & toggle the selector switch between tanks while I crawl around under the truck & listen?
Here's something else. The day after I bought the truck I switched to the front tank while driving & it ran fine for the next 5 mins until it was shut off. Then it would not start on the front tank. Find it a little hard to believe that the front tank decided to go awol the day after I bought it - Murphy's law? Have tried switching tanks while driving again (on an empty stretch of road) & the engine dies immediately. Read somewhere about the high pressure pump pulling out of the tank even if the in-tank pump was not working, probably not?
Going to contact seller to see if there was a problem with the front tank.
thanks for the info.

The in-tank pump will only run for 1-3 seconds. You only have (1) pump in each tank. There is no high pressure pump outside on the frame.

Do a search concerning user "SubFord" and "fuel pump" if you need a reference for jumping the F.P. lead frot he DLC connector. This may save you money, time and many headaches.

Yep, yer right. There's a current post addressing much this same issue = Fuel System Problems.... HELP!
I'll subscribe to that as well.

What is meant by "in-tank pump will only run for 1-3 seconds"?

thanks timbersteel

The 1-3 run is controlled by the computer, it shuts the pump off if you don't continue with starting the engine. You can make the pump run continuous for testing purpose by jumping 2 to 6 on the test plug.

Voltage check at the switch?
 

I had the same problem on my 88 before I sold it. As it turned out, when checking with a meter, I had no line side voltage on the switch for that tank, yet no bad fuse. I had to run another wire from a fused 12vdc source at the fuse panel to the line side pole of the switch for that tank, and solved it. Had an open somewhere!

Oh, so *that's* what is causing these high gas prices. I thought it was the gov't not letting our oil companies drill. Another lie from the dirty right wing. Gumby start using that front tank right away, I am due for a fillup soon! :-)

So I had the same issue with my 94 f150, except the front tank was rusted out and the fuel pump is bad as well. However when i switch the selector switch to the front now ( i know theirs no fuel) but the wires are loose underneath, the truck immediately dies like something else is shorted. I checked the switch and its good. Any feedback. i have a new fuel tank , just need a pump. Also I dont see the transfer valve that has been referred to before?