Fuel pump getting no power.

Tiny
JAMES W.
  • MEMBER
There is one thing here that puzzels me here. I've seen where 1 or 2 injectors will bleed down and when the engine is restarted a couple of cylinders will be flooded and will limp for a bit before they clear out. But I've never seen where all of a sudden "all" the injectors went bad to the point that the engine won't even fire. You may want to follow merlin2021's suggestion and run a fuel pressure bleed down test with a gauge. Keep us posted.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
LIL_DRUMMER2009
  • MEMBER
  • 1988 FORD F-150
  • 6 CYL
  • 4WD
  • MANUAL
  • 110,000 MILES
Electrical problem
1988 Ford F150 6 cyl Four Wheel Drive Manual 110000 miles

on 1988 ford F-150 what is the proper way for checking the fuel pump relay and its wires to diagnos the problem. When I jumper 12v on the fuel pumps they run. Also the EEC relay clicks and turns on, from my understanding that is what sends volts to relay.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Yeah I will do the test and keep you posted, I guess I forgot to mention this all started after I degreased and washed the engine bay. But I checked all connectors and they are all dry and look good
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
BLUELIGHTNIN6
  • EXPERT
To learn how to check a relay, check out our Popular Service Repairs page. A link is below for your convenience...

http://www.2carpros.com/how_to/how_do_i_check_a_relay.htm

To test the wiring you will need a volt meter.

Thanks for using 2CarPros.com!
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
JAMES W.
  • MEMBER
Degreased and washed, huh. Have you checked all your fuses. Just a thought.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Well the truck has about 36 lbs of pressure at the fuel rail, it lost 4 lbs in 5 minutes, I started it and its running at 30 psi consistently, I pulled the vacuum line from the regulator and it jumps to 40 lbs with no fuel in the vacuum line. Yet still after the truck gets to operating temp and I shut it off it still won't start back up. Weak coil or ignition module? I'm stumped I don't know what the deal is
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
(HELP)
  • MEMBER
Why would shutting fuel off help weak spark? After losing 4 lbs in 5 min - "I started it" you said - how much does it lose when fault occurs?
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
I don't know I was thinking to much fuel spark was to weak or not firing right under compresion. I'm out of ideas.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Oh and the fuel pump does not run with the key off, it runs how it supposed to
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
PANDA1
  • MEMBER
  • 1988 FORD F-150
Electrical problem
1988 Ford F150 V8 Two Wheel Drive Automatic

If the fuel pump relay switch goes bad will it prevent the vehicle from starting even when you bypass it?
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
JAMES W.
  • MEMBER
We're missing something here. We need to look "outside the box" so to speak. When the engine is warm and you unplug the FP relay, does it start right up, or do you have to crank for a bit? Do you need to floor board it to get it started? Do you get a cloud of smoke out the tailpipe when it starts. These are the type of problems that keep me awake at night. Please advise.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
When you bypass the relay, can you hear the fuel pump running?
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Well any ideas? The truck will start first thing in the morning, after its warm it won't start, it just cranks over and over(with spark) ne one, any ideas
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Um when I unplug the fp relay it does not start right up, it turns over 4 or 5 times then it starts. If I don't plug it back in right away it will stall again. Once I plug it in it runs good, no smoke, no misfiring, no rough idle, runs smooth as can be. It will run all day if I leave it running without any problems at all. But the second I shut her down, it does the same thing again.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
JAMES W.
  • MEMBER
OK, when we figure this one out, it will be for the record book. From what you've posted, the truck isn't flooding and the injectors aren't bleeding. You may have an injector or two that are weeping a little bit, but thats not why it won't start. Let's check injector pulse with engine warm and FP relay installed. If you have, or have access to, a "noid light", it just plugs into the injector connector, or you can use a regular "incandescent" test light. Try this and let me know if you get a pulse.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Well i'll get back to it tomorrow, thanks for the help and I will keep you posted.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Test pump and regulator like this:
HIGH PRESSURE FUEL PUMP 1. Check fuel tank(s) for adequate fuel supply. Check for fuel leaks at fittings and lines. Install jumper lead to fuel pump test terminal of VIP test connector. See Fig. 1 . Use a test lead long enough to reach under vehicle. Install fuel pressure gauge. Turn ignition switch to the "RUN" position. ground jumper lead and refer to FUEL PUMP PRESSURE WITH ENGINE RUNNING table. If fuel pressure is within specification, go to step 5). If fuel pressure is not within specification, go to step 2). Fig. 1: VIP Test Connector Courtesy of FORD MOTOR CO. FUEL PUMP PRESSURE WITH ENGINE RUNNING 2. If fuel pressure is low but greater than 3 psi (indicates pump is working), go to step 3). If not, go to step 4). 3. Check fuel system for plugged fuel filter or restricted fuel lines. Check for low voltage at the fuel pump (voltage should be with .5 volt of battery voltage). Disconnect fuel return line. If fuel is returning , adjust or replace pressure regulator. If filters are clear, voltage correct and no fuel return, replace fuel pump. 4. Ensure that battery voltage and ground are present at fuel pump connector. If circuits and voltages are correct, replace fuel pump. 5. Disconnect grounded test lead and note fuel pressure. Fuel pressure should remain within 2 psi for 3 minutes after disconnecting test lead. If fuel pressure holds, go to step 7). If not, go to step 6). 6. Inspect for fuel leaks. If no leaks are found, disconnect and plug fuel return line. ground test lead and raise pressure to normal level. If fuel pressure now holds, replace pressure regulator. If not, replace fuel pump. 7. Disconnect vacuum to fuel pressure regulator and start engine. Fuel pressure should within specification of FUEL PRESSURE WITH ENGINE RUNNING table. If fuel pressure is correct, go to step 9). If fuel pressure is not, go to step 8). 8. If fuel pressure is low, check fuel filter, fuel pressure regulator adjustment, fuel line restrictions or voltage to fuel pump. If all systems are normal, replace fuel pump. 9. With engine idling and fuel pressure regulator vacuum hose disconnected, measure fuel pressure. Accelerate rapidly and note fuel pressure. If fuel pressure drops more than 5 psi, repeat step 8). If fuel pressure does not drop, fuel system is operating correctly. CAUTION: Fuel system is under pressure. Before removing any fuel lines, depressurize fuel system. Disconnect inertia switch and crank engine for a minimum of 15 seconds to depressurize system. Application Pressure 2.3L 30-45 psi 2.9L 30-45 psi 3.0L 30-45 psi 4.9L 45-60 psi 5.0L 30-45 psi 5.8L 30-45 psi 7.5L 30-45 psi Page 1 of 1 FUEL PUMP - ELECTRIC -1988 Ford Pickup F150 3/6/2009


http://www.2carpros.com/forum/automotive_pictures/62217_vip_1.jpg

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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
DIXON1
  • MEMBER
  • 1987 FORD F-150
  • 200,500 MILES
My truck has dual tanks and which ever tank is selected and the inline pump continue to run with the switch off also the relay buzzs while the key is off I am totally at a loss over this issue any help will be greatly appreciated
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
I've made a new discovery, i'm not sure if it is normal or not. The truck starts up first thing in the morning and runs at a smooth 30 psi of fuel pressure. When it gets warm it runs at 30 psi but my needle shakes a little, then when I shut the truck off the fuel pressure goes from 30 to 37 in about 4 or 5 seconds. That may be normal i'm not sure. Any thoughts
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
CJ MEDEVAC
  • EXPERT
POSSIBLE FUEL PUMP RELAY'S CONTACTS ARE STUCK TOGETHER

SOMETIMES A GOOD THUMP WILL KNOCK 'EM LOOSE

IF SO, REPLACE IT ANYWAY---I'LL DO IT AGAIN

THE MEDIC
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)

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