Fuel pump wont run

JGarris95XLT

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I have scoured the other threads, and got some useful information, main thing I'm trying to figure out is where all the grounds are what color wire and how to find them. I'm only getting 8.3 volts to a new pump that I probably didn't need with a brand new battery that I probably did need.
 

miesk5

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I have scoured the other threads, and got some useful information, main thing I'm trying to figure out is where all the grounds are what color wire and how to find them. I'm only getting 8.3 volts to a new pump that I probably didn't need with a brand new battery that I probably did need.
Yo J
Fuel pump ground is G100. It's a black wire to top of radiator support.
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FYI,
No Start, Low State of Battery Charge or Buzzing or Humming Noise from the Fuel Pump after the Engine has been Shut Off Caused by Sticking Fuel Pump Relay TSB 90-18-3 for 83-90 Bronco, Bronco II, Econoline, F-150, F-250, F-350, Ranger & Many Others
 

JGarris95XLT

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Thanks @miesk5!
G100 is good.
Really not sure what to do next. Think I've got too many tabs open trying to figure it out.

10 volts 1 lead to ground at inertia switch, jumped it out, nothing.
8.3 volts on one of the leads at the pump, none at the others. This is weird.
 

JGarris95XLT

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I just remembered the fuel gauge did peg out once or twice a day or so before the breakdown.

Broke down at highway speed. Engine shut off, that was it.
Found that the front two bolts holding up the tank had apparently backed out, causing tank to sag. There wasn't much fuel in it, so I jumped to the conclusion that the pump had to have gone out.

Secured the tank.
Cut access (need to find the best way to cover that back.)

Installed new pump

Swapped relay, good.
Connections at relay look good.

Pump still won't prime or anything.

KOEO codes 542 and 543.

New battery.
 

miesk5

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I just remembered the fuel gauge did peg out once or twice a day or so before the breakdown.

Broke down at highway speed. Engine shut off, that was it.
Found that the front two bolts holding up the tank had apparently backed out, causing tank to sag. There wasn't much fuel in it, so I jumped to the conclusion that the pump had to have gone out.

Secured the tank.
Cut access (need to find the best way to cover that back.)

Installed new pump

Swapped relay, good.
Connections at relay look good.

Pump still won't prime or anything.

KOEO codes 542 and 543.

New battery.
 

miesk5

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Yo J,
  • Note: Due to the internal circuitry of the PCM, a left/front HO2S signal short to power could produce a DTC 542 or 543.

DIAGNOSTIC TROUBLE CODE (DTC) 542:​

  • DTC 542 indicates that one of the following has occurred:
    No Start:
    • Inertia Fuel Shutoff (IFS) switch not reset or electrically open (if in secondary circuit).
    • Open circuit between the fuel pump and FPM circuit connection to the power-to-pump circuit.
    • Poor fuel pump ground.
    • Fuel pump electrically open.
  • Engine Starts:
    • Fuel pump secondary circuit short to power.
    • Fuel pump relay contacts always closed.
    • Open in FPM circuit between PCM and connection to the power-to-pump circuit.
    • Left/front HO2S short to power (dual HO2S applications).
    • Damaged Powertrain Control Module (PCM).
Does the engine start (for trucks with dual fuel tanks, verify tank selector is in the same position it was when KOEO DTC 542 was received)?
YesNo
GO to J11.GO to J15.

J11 VERIFY THAT FUEL PUMP IS OFF​

  • Key on, wait five seconds.
  • Listen for motor noise from fuel pump (it may be necessary to listen by fuel tank).
Is fuel pump off?
YesNo
GO to J13.GO to J12.

J12 CHECK FOR FUEL PUMP RELAY
ALWAYS CLOSED​

  • Key off.
  • Locate and disconnect fuel pump relay.
  • Key on.
Is fuel pump off with relay disconnected?
YesNo
REPLACE fuel pump relay. RERUN Quick Test.SERVICE short to power in power-to-pump/FPM circuit. (For applications with Relay Block, also CHECK fuel pump prime plug circuit (if equipped). REFER to schematic). RECONNECT fuel pump relay. RERUN Quick Test.

J13 CHECK FPM CIRCUIT CONTINUITY​

  • Key off.
  • Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
  • Install breakout box, leave PCM disconnected.
  • Disconnect fuel pump relay.
  • Measure resistance between Test Pin 8 (Test Pin 19 for ******/Tracer) at the breakout box and power-to-pump circuit at the fuel pump relay vehicle harness connector.
Is resistance less than 5.0 ohms?
YesNo
For dual HO2S applications:
RECONNECT fuel pump relay. GO to J25.
All others:
REPLACE PCM. REMOVE breakout box. RECONNECT fuel pump relay. RERUN Quick Test.
SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.

J15 CHECK INERTIA FUEL SHUTOFF (IFS) SWITCH​

  • Key off.
  • Locate and disconnect Inertia Fuel Shutoff (IFS) switch (verify that switch is reset).
  • Measure resistance between the C and NC pins of the IFS switch. (For ******/Tracer and Probe, measure between GND pin and FP pin).
Is resistance less than 5.0 ohms

YesNo
RECONNECT IFS switch. REFER to Fuel/Engine Group in Service Manual, (Electric Fuel Pump) for open in power-to-pump circuit, poor fuel pump ground, open in fuel pump, etc.REPLACE or RESET IFS switch. RERUN Quick Test.

5A)
 

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miesk5

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Yo Part 2 due to a so called frigging "exceeding 10,000 post count" violation

J20 DIAGNOSTIC TROUBLE CODE (DTC) 543: DOES ENGINE START?​

  • DTC 543 indicates a fuel pump secondary circuit failure between the B(+) supply and the FPM connection to the power-to-pump circuit.
    Possible causes:
    No Start:
    • Open circuit between the B(+) supply and the FPM connection to the power-to-pump circuit.
    • Fuel pump relay contacts always open.
  • Engine Starts:
    • HO2S short to power (dual HO2S applications).
    • Damaged Powertrain Control Module (PCM).
Does the engine start?
YesNo
For dual HO2S applications:
GO to J25.
All others:
REPLACE PCM. RERUN Quick Test.
GO to J21.

J21 CHECK FOR B(+) TO FUEL PUMP RELAY​

  • Key off.
  • Disconnect fuel pump relay.
  • Measure voltage between B(+) circuit at the fuel pump relay vehicle harness connector and battery negative post.
Is voltage greater than 10.5 volts?
YesNo
GO to J22.VERIFY integrity of fuse/fuse link for B(+) supply to fuel pump relay. If OK, SERVICE open in B(+) circuit. RECONNECT fuel pump relay. RERUN Quick Test.

J22 CHECK POWER-TO-PUMP CIRCUIT CONTINUITY​

  • Key off.
  • Fuel pump relay disconnected.
  • Measure resistance between power-to-pump circuit at the fuel pump relay vehicle harness connector and the battery negative post.
Is resistance less than 10.0 ohms?
YesNo
REPLACE fuel pump relay. RERUN Quick Test.SERVICE open in power-to-pump circuit between FPM splice and fuel pump relay. REFER to schematic. RECONNECT fuel pump relay. RERUN Quick Test.

J25 CHECK LEFT/FRONT HEATED OXYGEN SENSOR (HO2S) FOR SHORT TO POWER​


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  • Note: Due to the internal circuitry of the PCM, a left/front HO2S signal short to power could produce a DTC 542 or 543.
  • Key off.
  • Disconnect left or front HO2S sensor.
  • Measure resistance between HO2S signal pin and KEY POWER pin at the HO2S sensor connector.
Is resistance greater than 10,000 ohms?

  • HO2S Connector
YesNo
GO to J26.REPLACE HO2S. RERUN Quick Test. CLEAR Keep Alive Memory (REFER to Quick Test Appendix, Section 5A).

J26 CHECK HO2S CIRCUIT FOR SHORT TO POWER​

  • Key off.
  • Left or front HO2S disconnected.
  • Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary. Leave PCM disconnected.
  • Key on.
  • Measure voltage between the HO2S signal at the HO2S vehicle harness connector and chassis ground.
Is voltage less than 2.0 volts?
  • HO2S Vehicle Harness Connector
YesNo
REPLACE PCM. RECONNECT HO2S. RERUN Quick Test.SERVICE short circuit. RECONNECT PCM and HO2S. RERUN Quick Test. CLEAR Keep Alive Memory (REFER to Quick Test Appendix, Section

FYI;
Found this 1995 Bronco EVTM, partial by Seattle FSB @ https://www.supermotors.net/registry/20487/76451-2
 

JGarris95XLT

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Man this is awesome thank you! I've got something to go on now. I'll let you know what I find thanks a lot!
 

JGarris95XLT

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This is where I'm at. So there's no power to any of the terminals where the relay plugs in. I found two fusible links by the starter solenoid, both have continuity. Not sure how to trace power between the battery and the relay box, or could it be anywhere between the fuel pump and the battery and the relay?
 

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JGarris95XLT

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Okay I tried that test again. I do have 12 volts at one of the terminals with the key on, some lower voltage at another terminal, but still no voltage to the terminals with the key off.
 

JGarris95XLT

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Looks like one of the two capacitors on there is burst, and the 56ea chip? Has some burn discoloration on the outside of the board?
 

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miesk5

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Looks like one of the two capacitors on there is burst, and the 56ea chip? Has some burn discoloration on the outside of the board?
Yo J,
I have very poor vision so let lets call in others with better vision.
My much-better-half says that one capacitor is leaking; and board burn discoloration is a suspect because the board is covered with a conformal coating to protect it against moisture and contamination, but the electrolyte has seeped under or through that coating and discolored the board in places.
 

JGarris95XLT

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Great, so I've got the PCM out as you can see. I would like to run a test on it, just for my own peace of mind. I changed a lot of control boards doing residential air conditioning work, of course they don't have the conformal coating. Anyway so I would like to hit it for my own peace of mind if nothing else. From what I have read on other threads, there is only one pin that goes to the fuel pump correct? So I should be getting what resistance from that pin to ground? Any other way I should test it to make sure?
 

JGarris95XLT

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Miesk5 can I run a pcm with GB instead of JB at the end of the serial nomenclature? Looks the same best i can find TIA!!
 

miesk5

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Yo J,
What engine and trams do you have in the 95?
For a YARD SEARCH on-line, I use;
Hollander Quality Replacement Parts | Find Used Auto Parts | Online Locator
A yard that uses Hollander Interchange can search other yards and have it shipped including some Canadian yards.
"...For over eighty years, Hollander has been making the best tool for fast, interchangeable part matches. The new Edition Hollander Interchange contains more interchangeable options than ever before.
The Hollander Interchange provides auto recyclers and auto collectors, rebuilders, and others with the easiest and most comprehensive solution for identifying interchangeable auto parts..." See their yard Directory @ Seller Directory | Used Auto Parts | Hollanderparts
Can select a certain part, such as in this instance,

Search By: 1995 >Ford > Bronco > Electrical > Engine Ecm > Fitment​

You must be registered for see images attach
or contact autocomputerexchange.com for rebuilding your EEC AS LONG AS CIRCUIT BOARD IS N0T BURNT.
 

JGarris95XLT

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Yo J,
What engine and trams do you have in the 95?
For a YARD SEARCH on-line, I use;
Hollander Quality Replacement Parts | Find Used Auto Parts | Online Locator
A yard that uses Hollander Interchange can search other yards and have it shipped including some Canadian yards.
"...For over eighty years, Hollander has been making the best tool for fast, interchangeable part matches. The new Edition Hollander Interchange contains more interchangeable options than ever before.
The Hollander Interchange provides auto recyclers and auto collectors, rebuilders, and others with the easiest and most comprehensive solution for identifying interchangeable auto parts..." See their yard Directory @ Seller Directory | Used Auto Parts | Hollanderparts
Can select a certain part, such as in this instance,

Search By: 1995 >Ford > Bronco > Electrical > Engine Ecm > Fitment​

You must be registered for see images attach
or contact autocomputerexchange.com for rebuilding your EEC AS LONG AS CIRCUIT BOARD IS N0T BURNT.
Thanks man hope your eyes are doing well! I've got a powertrain control module with the matching numbers coming from a truck with the same drivetrain 5.0 with the e4od. Should be in before 7 this evening, looking forward to it! I'll check these guys out because I want to get my module rebuilt if possible to have one in the glove box for a spare
 

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