My 84 F250 has 460 engine. Running fine, cut it off and now won't start. You can usually hear the fuel pump or fuel tank selector valve hum when the key is on but no hum. Replaced fuel tank selector valve, nothing. I've checked all the fuses, ok. I'm getting power to the fuel tank selector valve, but it not pumping fuel. Anyone have any suggestions as to what I can try?

 

Did you check the condition of the relay's socket?

 

I have a 1982 f250 with the 400. I installed a rebuilt carb and I wasnt getting fuel. I ended up getting a new fuel pump and it solved the problem. The fuel tank selector valve doesnt pump fuel the fuel pump does. Mine was on the engine block(mechanical) and easy to replace. It only pumps when the engine is cranking/running. Maybe an even easier fix would be the fuel filter. When was the last time that was replaced. There might be water frozen in the line. Disconnect the line into the carb crank the engine over and see if you are getting strong spurts of fuel. Weak spurts mean a bad pump, blocked line or bad filter. Just a few ideas I came up with when I wasn't getting fuel.
-Evan

 

Does that model have some sort of impact switch (I forget its real name) that shuts off
power to the fuel pump(s) in the event of a crash? In some of these trucks, I think those
switches are located on the passenger side vehicle interior, down behind the vent/kick
panel. If you have such a switch, that could be your problem; you should hear the fuel pump
for at least a few seconds upon initially turning the key to RUN.

A voltmeter would be a really useful tool, e.g.:
http://www.harborfreightusa.com/usa/...o?itemid=92020

 

that would be the inertia switch.they are located on the trans tunnel just above the carpet on the passenger side fire wall.there will be a white piece of plastic on top,jsut press it down.some times these trip if you hit a big bump,or somebody bumps the truck or just slamming the door.
on my 86 i cannot here the pumps at all,never could with the stock exhaust and especially now with the turbo mufflers.LOL

 

I did reset that interia switch yesterday. Nothing. I was thinking of going there today and bypassing that switch and trying new relays. A post suggests changing the fuel pump. I haven't done that yet. Like I said, I changed the fuel tank selector valve because of the absent hum I normally hear under the drivers seat where the bed connects. Would a bad fuel pump cause it not to hum?

 

Quote:

Originally Posted by lovinmytruck

Would a bad fuel pump cause it not to hum?

Definitely; the hum is from the electric motor, and a motor that doesn't turn
won't hum.

Man, get yourself a cheap voltmeter at Harbor Freight or WalMart or sumthin',
use it to help you figure out what the actual problem is instead of merely
replacing parts *****-nilly....

 

yeah, I have checked the the selector valve and the switches and all that with the meter everythings got power. I went over and bypassed that interia switch, still doesn't work. Tried a new (I know, know) fuel pump relay still nothing. Going to try and search for a ground not connected, I just don't know.

 

like I said before I can't hear my pump,just before. my rear pump craped out it hummed really loud.an electric motor will hum if it's under load or it's locked up.under normal load it will hum a bit as it's pumping fuel.
as said in previous post get a multimeter.on the starter relay there should be 2 smaller wires,one is to engauge the relay,the other is to turn the intank pumps while the engine is cranking.use a jumper wire from the battery to this wire,then crawl under the tank and listen to see if the pump is running.if it's not drop the tank and check for power at the plug,it there is power at the plug the pump is bad,but I can't see both pumps going bad at the same time.

 

Quote:

Originally Posted by 86bigred

like I said before I can't hear my pump

Yeah, but that's with your engine running, correct? My comment is based on
what I know of my fuel-injected daily driver - I can turn the ignition on (but not
start the engine) and I can hear the pump run for a few seconds; I can even hear
the relay under the dash that turns it on & off. Not trying to nitpick or be a jerk,
just be clear.

Another thing he can do to test his pump with the tank dropped (in addition to
what you suggested) is to hook up an ohm meter to the two leads on the socket
that lead to the pump; if there are 0 ohms resistance, the pump is burned out.

 

your hearing the high pressure pump in the frame rails.yes when you turn the key it will pressure up the fuel rails and injectors so the engine will start (efi).these intank pumps will not energize until the key is in the start position.his truck has a carb ,and doesn't have the inframe high pressure pump that your daily driver has.you won't hear the pumps in the tank as they are submerged in gas.i'm not trying to be a jerk as well but the carb version is different from the efi,as the carb already has fuel in it to start the engine,and if not when you crank the engine that other wire on the relay will energize the pump to fill the carb while cranking.

 

Quote:

Originally Posted by 86bigred

your hearing the high pressure pump in the frame rails.yes when you turn the key it will pressure up the fuel rails and injectors so the engine will start (efi).these intank pumps will not energize until the key is in the start position.his truck has a carb ,and doesn't have the inframe high pressure pump that your daily driver has.you won't hear the pumps in the tank as they are submerged in gas.i'm not trying to be a jerk as well but the carb version is different from the efi,as the carb already has fuel in it to start the engine,and if not when you crank the engine that other wire on the relay will energize the pump to fill the carb while cranking.

OIC.

But....

My daily driver is a 1986 Ford Tempo with throttle-body EFI, the only fuel
pump it has is in the tank. I know this for a fact cuz I recently had to replace
the thing, a thoroughly sucky procedure when you don't have an overhead lift
and can't stand under the thing to drop the tank.

 

oops i though you were talking about a truck sorry.i have an 86 tempo as well and yes when the key is turned i hear the pump.when the fuel is pressurized it puts a load on the pump and thats why we here it.

 

Quote:

Originally Posted by 86bigred

i have an 86 tempo as well

Wow!!!!



Totally off-topic here, but I got mine from my parents about 15 years ago, they
used to give me their old cars after 10 years/100,000 miles. It has the 2.3L (VIN
code X I think) and the 5-speed manual; I keep fixing it and refuse to get rid of it
because it gets 26 MPG in the city, that means a lot at $4/gal.

 

I guess I should have named this thread not hearing fuel selector valve. I know I'm coming across like a dummy, that is why I asked the question from all of ya. The truck won't even start. See, normally, when ya turn the key on the selector valve hums. Then that in turn "pumps" the gas to and from the tanks or so I thought. Anyways, that valve is not humming like it has since the first day I got the truck. It's brokedown 30 minutes from here and now I'm broke buying that damn valve it obviously didn't need. This weekend-payday I'll go mess with it some more. Thanks guys for your help....I'll let ya know how it turns out. I still have a couple relays to check out and go through it to look for a ground wire not grounded. I think a for sale signs going on it when I get this problem solved.