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Fuel Issues.

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jmadigan

Fuel Issues.

Hello all
I have a 1983 f250 460 4x4 4 speed with the in tank low pressure pumps. First winter owning it and im chasing a fuel problem. Carb stays full of fuel starts up fine then drains bowls I crank to refuel carb then it drains again i repeat this 3 or 4 times and then it will run just fine. It only happens in the cold. This is telling me the pumps dont prime the lines. Any ideas what could be causing this? Im thinking of running a momentary switch to prime the lines to prevent this from happening any ideas on where to hook a push button switch to turn on the pumps to prime? but shouldnt the pumps be priming in the run position?

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

Gary Lewis

Re: Fuel Issues.

Administrator

I'm confused. The carb stays full of fuel over night, but when you start it the carb loses fuel? Where does the fuel go - into the engine or on top of the engine?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

85lebaront2

Re: Fuel Issues.

Administrator

In reply to this post by jmadigan

Ok, first issue is Ford changed the "hot fuel handling package" which is what you have every year from 1983-1987 so the first thing is to find a good (don't trust Haynes or Chiltons) wiring diagram.

Basics of the system are found here: https://www.garysgaragemahal.com/460-fuel-systems.html however the wiring diagrams are not there for all years. The fact that it will prime indicates the pumps and wiring are there, priming is via the small blue fusible link on the starter relay (connected to the "I" terminal). On the back of the engine, there is a small switch teed into the oil pressure sender pipe:

Pay no attention to the automatic/standard transmission note, it should be with Hot Fuel and Without Hot Fuel.
From it a harness runs along the inside of the driver's side valve cover and over to the wiring on the inner fender. On the firewall is a fuel pump relay that this switch powers causing it to change from the priming wire to a battery power source. If the relay is clicking when the oil pressure comes up, then it is probably bad, if not then the oil pressure switch may be bad. If you unplug and jumper the plug terminals, the pump should come on and run, if you get a relay "click" and no pump, then it probably is the relay.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

grumpin

Re: Fuel Issues.

In reply to this post by jmadigan

The fuel pump should come once you start cranking the engine and stay on with oil pressure IIRC.

I wouldn’t think your carb is draining, I think it’s cold and didn’t stay running.

How is your choke adjustment?

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

jmadigan

Re: Fuel Issues.

In reply to this post by 85lebaront2

I will give this all a look and report back

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

jmadigan

Re: Fuel Issues.

In reply to this post by grumpin

Let me also say I put a quick fuel brawler with a manual choke on the truck it has sight glasses for the float levels so before I start in the morning I can see the float levels are fine it starts up fine but I can watch the fuel bowls empty while it runs crank the engine over refill the bowls and repeat 3 or 4 times (about the time the battery is throwing a white flag) then the bowls will refill on their own after a while. It happens every morning or after work if it’s below freezing. Above freezing this doesn’t happen.

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

jmadigan

Re: Fuel Issues.

In reply to this post by 85lebaront2

Blue fuseable link wire is on the starter wire on the terminal not in the “I” is this my problem?

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

Gary Lewis

Re: Fuel Issues.

Administrator

In reply to this post by jmadigan

Given that description, which helps my understanding a bunch, I'd guess that your oil pressure switch isn't closing and that causes the fuel pump not to run when in Run.

I would put a jumper across the switch to bypass it and see if that causes the truck to run.

Gary, AKA "Gary fellow": Profile

jmadigan

Re: Fuel Issues.

I think the oil switch is working because after the bowls finally fill on the 4th or 5th try it runs normal. Should I jumper the wires anyway and try it in the morning. I also put the fuseable link in the I position on the relay.

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

85lebaront2

Re: Fuel Issues.

Administrator

In reply to this post by jmadigan

That should make the pump(s) run continuously as it feeds the center contact in the relay, the fact that it isn't running continuously makes me suspect the relay. Here are the diagrams from my AllData Pro:

Bill AKA "LOBO" Profile

jmadigan

Re: Fuel Issues.

Makes you suspect the starter relay or one of the fuel pump relays?

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

85lebaront2

Re: Fuel Issues.

Administrator

The fuel pump cutoff relay. What bothers me is the way things are hooked up now the pump should be running even with the key off. The fact that it isn't makes my suspect that there is an open circuit somewhere between the blue fusible link and the tank selector relay.

Fuse link T is the blue fusible link, the way it is connected, the pink with a black hash wire should have battery voltage through the diode to the relay socket, you should also have power at the fuel pump cutoff relay

640, Red with Yellow Hash is powered by the oil pressure switch when closed; 57, black is ground; 37, Yellow is powered directly from the battery through the inertia switch (inside on the heater duct, passenger side); 787, Pink with Black Hash, is powered when the relay coil is powered by the oil pressure switch. If the power is on circuit 787, then the pump will run.

You need to check these items and figure out how hosed up the wiring is (

maybe) and then work on correcting it.

Bill AKA "LOBO" Profile

mat in tn

Re: Fuel Issues.

where "was " the blue fuse link before?

jmadigan

Re: Fuel Issues.

In reply to this post by 85lebaront2

I’ll do my best

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

jmadigan

Re: Fuel Issues.

In reply to this post by mat in tn

To the starter side of the starter relay it’s not on the I terminal and running the same. I haven’t checked to see if it starts better cold yet

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

mat in tn

Re: Fuel Issues.

on the starter terminal of the solenoid? the one the wire from the ignition switch goes to also? that would only be hot while holding the key in the start position. off as soon as you let go of the key.

jmadigan

Re: Fuel Issues.

The blue fuseable link wire was connected to the starter solenoid on the big terminal that goes to the starter so yes hot in run

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

mat in tn

Re: Fuel Issues.

the two large terminals are for the starter "only". one is battery voltage un switched. the other is switched to the starter only and is not energized once you let off the key. the two small terminals are different. the "s" terminal operates the solenoid(relay) from the key/ignition switch.
some circuits which require constant 12v will use the battery side of the solenoid/relay as a terminal point and that's where you will see two or more wires with ring terminals mounted there. like the voltage for the heavy side of the fan relay, fuel pump relay, ecu relay, headlamp switch etc. then those relays will be operated by the ignition switch,

Gary Lewis

Re: Fuel Issues.

Administrator

In reply to this post by jmadigan

jmadigan wrote

The blue fuseable link wire was connected to the starter solenoid on the big terminal that goes to the starter so yes hot in run

That is not correct. The big terminal that goes to the starter only has power in Start, not Run. So if that's where you have the blue wire then that is a problem. All fuse links that go to the starter relay go on the battery terminal, not the starter terminal.

Gary, AKA "Gary fellow": Profile

jmadigan

Re: Fuel Issues.

In reply to this post by 85lebaront2

Does this wire that should be connected to the “I” terminal have the diode on it as well? Last night I moved the blue fuseable link with the diode to the “I” terminal and there was no change in starting it was a pain to get going I had to manually fill the bowls with some gas until it picked up fuel. I swapped the relay with a spare I had that may also be questionable. The wiring is hacked in this truck there is a 5 pin relay in the fuel cutoff (relay without the resistance wire) with one of the wires clipped off that’s another potential issue I have seen I’m not sure which wire it is but I will check when I’m home. Overall same issue pain to get running but once it picked up fuel it drove fine.

Truck Norris: 1983 F250 460 4speed 4x4
Silver Bullet: 2001 F350 7.3L 6speed swapped 4x4

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