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No fuel to carb

Tiny
IRONHORSE
  • MEMBER
  • 1984 FORD F-250
  • V8
  • 4WD
  • MANUAL
  • 103,000 MILES
No fuel or very little to carb, truck starts if you pour fuel in carb. Has frame mounted fuel tank selector valve. I can hear relay on fire wall and tank selector valve click when key is turned on. I do not hear either fuel pump hum. Can I test the selector valve? How can I test the fuel pumps while still in the tank?
What wires (color) would I connect a jumper to.
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Saturday, January 16th, 2010 AT 11:39 AM

19 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Dual Tanks With ignition switch in "START" position, current flows to tank selector relay. Depending on which position the fuel tank selector switch is in (FRONT or REAR), current then flows to front or rear fuel pump. With ignition switch in "START" or "RUN" position and oil pressure switch closed (engine running), the fuel pump cut-off relay is energized and current flows to either pump. With ignition switch in "RUN" position, the voltage to fuel pump is reduced by means of a resistance wire. This provides extra fuel pressure during engine starting. The inertia switch will open on impact and cut-off power to fuel pump cut-off relay in the event of a collision. TESTING ELECTRICAL CONTINUITY 1. Check fuel tank for adequate fuel supply. Check for leaks at all lines and fittings. Disconnect connector to fuel pump just forward of fuel tank. Connect a voltmeter to body wiring harness connector. 2. Turn ignition "ON". Battery voltage should be present, voltage should return to zero after approximately 1 second. Turn ignition switch momentarily to "START". Voltage should be approximately 8 volts while cranking. If voltage is not within specifications, check electrical system. Fig. 1: Ford Electric Fuel Pump Wiring Diagram FUEL PUMP OPERATION 1. Disconnect fuel return line at throttle body. Connect hose from throttle body fitting to a calibrated container of at least 1 quart capacity. Connect pressure gauge (T80L 9974 A) to fuel diagnostic valve on fuel charging assembly. 2. Disconnect connector to fuel pump just forward of fuel tank. Connect an auxiliary wiring harness to fuel pump. Energize pump for 10 seconds by connecting harness to a fully charged 12 volt battery. If fuel pump does not run, check connection at fuel pump. 3. Fuel pump is operating properly if fuel pressure is 35-45 psi (2.5-3.2 kg/cm 2 ) and if fuel flow is a minimum of 10 ounces. Fuel pump must maintain a minimum of 30 psi (2.1 kg/cm 2 ) immediately after de-energization. If all 3 conditions are met, fuel pump is operating properly. Check for engine and electrical problems. 4. If pressure conditions are met but flow is not, check for blocked filter(s) and lines. After correcting blockage, retest fuel pump. If flow is still not met, replace fuel pump. If fuel flow is met but pressure is not, check for worn or damaged pressure regulator valve on throttle body. 5. If both pressure and flow conditions are met but pressure cannot be maintained after de- energization, check for leaking injector valve(s), and/or pressure regulator valve. If both check okay, replace fuel pump. INERTIA SWITCHIn the event of a collision, contacts in inertia switch will open and shut fuel pump off. The fuel pump will shut off even if engine continues to run, engine will stop after fuel pump is off. It is not possible to restart engine until inertia switch is manually reset. The inertia switch is located behind instrument panel. To reset inertia switch, depress button on top of inertia switch.
1/16/2010 ...


https://www.2carpros.com/forum/automotive_pictures/62217_wdf_1.jpg


Schematic for color ID's.
Look for Carb Id tag if you need more info, post tag and if 2 or 4 barrell.


https://www.2carpros.com/forum/automotive_pictures/62217_carbtag_1.jpg

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Saturday, January 16th, 2010 AT 11:47 AM
Tiny
NOISYNICK
  • MEMBER
  • 2 POSTS
  • 1987 FORD F-250
  • V8
  • 4WD
  • AUTOMATIC
  • 129,000 MILES
This truck runs great if you let it warm up for 15 minutes. But it won't move a foot if you just start it and go with a reasonable warm up say 1 minute it will just die. And it becomes harder to start after it starts initually. If you give it a shot of ether it will pop right off if not you have to pump it alot if its sat 12 hrs or more. It will start fine if it doesn't cool off too much once you give it the initial warm up.
The emission controls and such are missing but i'm not sure that has helped or hurt it.
Any help would be greatly appreciated.
Thanks Nick
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Let me first say don't use ether on a vehicle it is hard on them use carb cleaner it is less volital. Now I need some info on this. Which engine is in it and does it have injection or carburation? As on the F-250 it can come both way's depending on the engine. How old is the fuel filter? Get back to me and we will go from there. Thanks and have a great day.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
NOISYNICK
  • MEMBER
  • 2 POSTS
It haS a 351 windsor with a 4 barrell carb made by holly for motorcraft. 1987 with an automatic transmission and 4 wheel drive.
If I were to install a new carb would you suggest One?
Fuel filter is new as is the air cleaner doesn't seem to make any difference if the air filter is there or not same trouble. Oh and BTW the choke is functioning and I have physically observed it opening and its closed for a cold star as well
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok it sounds like the accelorator pump in the carb is what is bad. Now if you step on the gas after it is running does it hesitate? I would either rebuild the Holley on it or I would buy a 650 CFM Holley to replace it with as Holley and Ford like each other very well. Let me know how it goes ok. Thanks
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
BLITZ50GH
  • MEMBER
  • 1 POST
  • 1972 FORD F-250
  • V8
  • 2WD
  • MANUAL
  • 54,000 MILES
When trying to crank my trunk it wont turn over. I checked the fuel lines, the fuel pump, and the fuel filter, they are all operational. I replaced the spark plugs. Its a new carburetor and the choke settings are right. If an ignitor is sprayed into the carburetor the engine will start but not stay running. It bogs down and stops.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Hi there,

Remove the fuel line into the carby and place a length of rubber hose over it and place open end into a jar, crank engine. If fuel pumping you will have a faulty needle and seat valve in the carby, if no fuel either the pump is not working, the pick up line is damaged or the tank is empty. Check all these things carefully.

Mark (mhpautos)
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
KHELLENDROS082208
  • MEMBER
  • 1 POST
  • 1969 FORD F-250
  • 83,430 MILES
I rebuilt the carb and she starts and runs like a champ. However after she warms up and I disengage the manual choke on my 1405 edelbrock carb, she sometimes pops up back through the carb. I give her a little gas and she's good for awhile. But inevitably pops back through the carb once in awhile. I've changed the plugs, wires, cap and rotor, replaced the factory fuel filter and installed an after market in line fuel filter. I've flushed the cooling system, brake system and power steering and trans. I've replaced the coil, thermostat, fuel line and pcv valve. Other than the occasional backfire through the carb, she runs awesome! Any help woild be much appreciated. Thank you, Will Fish.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,757 POSTS
Two things to look at. The ignition timing and make sure the accelerator pump is giving a steady stream when the throttle is opened slowly.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
JEFFROHOTROD
  • MEMBER
  • 31 POSTS
  • FORD F-250
I have a 79 ford granada with a 250 1 barrel carb. It is running rich and I can't seem to get the mixture right. How do I get the air/fuel mixture right? Thanks
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
RUDPRO
  • MECHANIC
  • 224 POSTS
I'm not familiar with your car but the correct way is to first make sure your timing is correct. Warm up the car to operating temperature. Turn the car off. Disconnect the vacuum hose from the distributor, if it has one, and plug the hose. Connect a vacuum gauge with a tee fitting to a vacuum line. Turn the idle mixture screw on the carburetor all the way in and back it out 2 turns. Start the car and adjust the screw until you have the highest steady vacuum reading possible. It should be about 20 inches of vacuum.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
BIG_JON_1
  • MEMBER
  • 1 POST
  • 1981 FORD F-250
Engine Performance problem
1981 Ford F250 V8 Four Wheel Drive Automatic

hi I have a 81 f250 full size 4x4 with a 6.6 v8 400 motor just took it from propane back to gas. Just wanted to know if I have to rebuild the carb on it as the last time it had fuel was in 91. Right now it will not start unless you use ether.

Please help.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Hi there,

The carby will need a total re build and chemical clean, corrosion will have built up in the carby and all the seals will be useless now, it should come back to life with a total re build.

Mark (mhpautos)
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
SHERIDAN65
  • MEMBER
  • 1 POST
  • 1979 FORD F-250
1979 Ford F250 V8 Two Wheel Drive Automatic

I have a 1979 Ford F250 Ranger that's really hard to start and often runs roughly. When I first start it, it starts and then dies; it often does this three or four times before it will finally keep running. I think that would be a choke problem, right? It has an automatic choke.

When I accelerate, it hesitates and sputters a little bit, but when I push the accelerator down further, it picks up speed like it should. When I floor it, the truck accelerates fast, with no apparent problem at all. Sometimes, it runs more smoothly than other times, but rarely as well as it should. I've tried adjusting the fuel mixture screws, but that didn't correct the problem. I've also put on new spark plugs, a new fuel filter, and a new air filter.

I had the truck repaired just over three weeks ago; at the time the carburetor was flooding so badly that gas was running out the top and sides. Gas still leaks out the driver's side of the carburetor a little bit, though it doesn't drip. Before the flooding started, the truck ran really well, as well as it's run since I've had it.

I would appreciate help with this problem. Thanks.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Hi there,

yes I feel that your problems are all concerned with the carby, if it is leaking fuel, there is a problem. Check the choke by removing the air cleaner top, with the engine cold, depress throttle once and see if choke butterfly activates, if not there is a problem, also there should be a choke fast idle as well, this steps up the idle while the choke is on, all these must be working. I feel that you need to get the carby sorted first.

Mark (mhpautos)
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
FORDMAN1971
  • MEMBER
  • 2 POSTS
  • 1979 FORD F-250
  • V8
  • 2WD
  • AUTOMATIC
  • 148,000 MILES
I have a 1979 Ford F-250. I just replaced the engine, with only minor modifacations made(dual exhaust, and 600 cfm edelbrock carb w/ spacer plate). Now, I have a "popping" or, hick-up when I try to accellerate, and also during sustained speed a crackle coming from the exhaust. Nothing happens at idle. What could cause this? The timing is set at about 8 degrees( not orig. Distributor, vacc adv. Seems to work.)New plugs also.
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the accelerator pump, main metering and power valve of the Carb. All okay test the ignition system if its within specs such as coil, magnetic pick-up, sparkplug gap and wire resistances

Type of Dizzy-electronic or points?
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
FORDMAN1971
  • MEMBER
  • 2 POSTS
Thank you for replying rasmataz. The carb is brand new. What is weird, is that when shutting the air/fuel mix screws- nothing happens. It should try to die. The ign. Box is also new. Perhaps a faulty part? How do I test these parts to narrow the problem down from fuel, timing, or ign?
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
You need to check the Carb, Adjusting the A/F mixture screw should drop or raise the idle speed-Also pull the throttle back and watch the accelerator pump squirting fuel if not -the pump is no good
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Wednesday, October 30th, 2019 AT 6:56 PM (Merged)

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