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Discussion Starter #21
$60 vs $400.... I'll take my chance on the cheaper one since the Motorcraft version with the sending unit probably uses a Carter (or Denso, or some other brand) pump in their assembly.

I'll let you guys know how it works out. Chances are good that this is my issue, but it is also possible that it's something else.
 

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Yo Aggie,
I missed this thread a few times!
"Diagnosis in a 94 from 1994 PCED OBDI-A, SECTION 9A: Fuel Delivery Systems
Source: by Ford
miesk5 Note, I modified this to address your 96;
EXCERPT:
Truck Engines
5.0 & 5.8​
ENGINE MODE​
ENGINE APPLICATION​
ENGINE
RUNNING
28-45 PSI​
KEY ON
ENGINE
OFF
35-45 PSI​

Note: Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.

If fuel lines/systems have been drained or evacuated, it may take up to 15 seconds to obtain the pressure specified.

FDS2 FUEL PRESSURE TEST
WARNING: BEFORE SERVICING OR REPLACING ANY COMPONENTS IN THE FUEL SYSTEM, REDUCE THE POSSIBILITY OF INJURY OR FIRE, AS OUTLINED UNDER "NOTES, CAUTIONS AND WARNINGS."

  • Key off.
  • Before releasing fuel system pressure at the Schrader fitting, observe the Warning Instructions to avoid fuel spillage and injury.
  • Install the fuel pressure tester.
  • ➡miesk5 Note, deleted the EEC IV Method of Grounding the fuel pump lead of the Data Link Connector (DLC) with a jumper at the FP lead.
  • Key On, Engine Off, to operate the fuel pump
  • Verify that the observed fuel pressure is within specified limits for the engine being checked.
  • Specification: Fuel System Pressure (Key On, Engine Off) Refer to "Fuel Pressure Specification Table."
Is fuel pressure within specification?
YesNo
GO to FDS3.If low:GO to FDS10.
If high:GO to FDS11.

FDS3 CHECK FUEL PRESSURE LEAKDOWN
Observe the "Notes, Cautions and Warnings" to avoid fuel spillage and injury.
Connect the Fuel Pressure Test Kit at the fuel pressure test point.

Key on, engine off.
Run the fuel pump for 30 seconds minimum.
Remove the test lead ground and note fuel pressure on the gauge.
Verify whether the fuel pressure remains within the specified 5 psi for 1 minute after the test lead is ungrounded.

FDS4 CHECK PRESSURE REGULATOR DIAPHRAGM CONDITION
Key off.
Connect Fuel Pressure Test Kit at Schrader fitting on rail. Observe Warning Instructions to avoid fuel spillage and injury.
Start engine and run for 10 seconds.
Stop engine and wait 10 seconds.
Start engine and run for 10 seconds.
Stop engine and remove vacuum hose from pressure regulator.
Examine vacuum port in the pressure regulator for evidence of fuel leakage through the diaphragm.
Is vacuum port free of any fuel?
Yes GO to Group 10 of the Service Manual for leak test.
No REPLACE pressure regulator and RERUN test FDS2.

FDS5 CHECK FUEL PRESSURE WITH ENGINE LOAD
Fuel pressure test kit installed.
Disconnect vacuum hose at the fuel pressure regulator and plug it.
Observe fuel pressure while driving vehicle with heavy accelerations.
Does fuel pressure reading remain within ± 3 psi during the test?
Yes UNPLUG vacuum hose and connect it to fuel pressure regulator. GO to FDS6.
No GO to FDS8.

FDS6 CHECK FUEL PRESSURE REGULATOR
Fuel pressure test kit installed.
Install vacuum gauge to intake manifold.
Start engine and observe both gauge readings.
Accelerate the engine speed to lower the vacuum gauge reading.
Does fuel pressure gauge reading increase as the vacuum gauge reading decreases, and/or does fuel pressure gauge reading decrease as vacuum gauge reading increases?
Yes REMOVE vacuum gauge and fuel pressure test kit. GO to Section 2A for other possible causes.
No GO to FDS7.

FDS7 CHECK VACUUM SUPPLY
Key off.
Vacuum hose removed from the fuel pressure regulator and plugged.
Install a hand operated vacuum pump to the fuel pressure regulator.
Start engine.
Observe fuel pressure while applying vacuum.
Does fuel pressure reading change as the vacuum changes?
Yes SERVICE vacuum system. REMOVE plug from vacuum hose and RECONNECT to fuel pressure regulator.
No REPLACE fuel pressure regulator.

FDS8 CHECK FUEL FILTER
Observe Warning Instructions to avoid fuel spillage and injury.
Key Off.
Install a second fuel pressure tester on Schrader valve equivalent installed between fuel pump and the in-line fuel filter, as close to fuel pump as possible.
Operate fuel pump as in FDS2 and compare pressure observed at fuel rail with the pressure observed at the fuel pump.
Is pressure at fuel pump within 5 psi of fuel rail pressure?
Note: When fuel pump is not in operation, the fuel delivery system is at the same pressure, regardless of location of pressure tap. Therefore, both gauges should read the same pressure when pump is not in operation. Any difference in pressure readings when fuel pump is not in operation is pressure gauge error.

Yes GO to Group 10 of the Service Manual for additional Description, Diagnosis and Testing.
No REPLACE in-line fuel filter and RECHECK pressure as in FDS2. If pressure is OK, GO to FDS3. If pressure is not OK, RECHECK fuel lines for kinks or other restrictions. SERVICE and RECHECK as in Step FDS2.

FDS9 CHECK VOLTAGE AT BOTH PUMP SPEEDS
Key off.
Connect DVOM between Inertia Fuel Shut-off (IFS) and chassis ground.
Start and run engine.
Read voltage at idle and at 3500 rpm.
Is the voltage near 9 volts at idle and near 13 volts at 3500 rpm?
Yes CHECK fuel pump ground connection and service. If OK, REPLACE fuel pump.
NO CHECK CCRM/VCRM for proper operation. CHECK fuses of the fuel pump circuits high and low. RERUN FDS2.

FDS10 CHECK REGULATOR FOR LOW PRESSURE CAUSES
Key off.
Remove return fuel line at fuel rail and connect short hose from rail to measured container of at least one quart capacity.
Key on, engine off.
Record fuel pressure and note whether fuel is being returned to measured container. Unground FP lead after 10 seconds or if container is more than half full.
Is fuel being returned while pressure is still low?
Yes REPLACE fuel pressure regulator and GO to FDS2.

No REPLACE fuel pump assembly. GO to FDS2.
Note: When replacing fuel pump, clean out tank and replace fuel filter.
MIESK5 NOTE; check connector on top of tank for faults/corrosion, etc.


FDS11 CHECK REGULATOR FOR HIGH PRESSURE CAUSES
Key off.
Remove return fuel line at fuel rail and connect short hose from rail to measured container of at least one quart capacity.
Key on, engine off.
Record fuel pressure and note whether fuel is being returned to measured container. Unground FP lead after 10 seconds or if container is more than half full.
Is fuel pressure within specification?
Yes GO to FDS13.
No REPLACE fuel pressure regulator and GO to FDS2.

FDS12 CHECK FUEL RETURN SYSTEM
Observe the "Notes, Cautions and Warnings" to avoid fuel spillage and injury.
Check the fuel return system(s) for restriction due to blockage, kinking, or pinching.
Remove the fuel return line at the fuel pressure regulator.
Apply 3-5 psi regulated shop air to the fuel return line.
Do you hear air entering either tank?
Yes REPLACE in-tank unit where air is entering. RECONNECT fuel return line.
GO to FDS2.
No GO to FDS13.

FDS13 CHECK FUEL RETURN SYSTEM
Key off.
Observe the "Cautions and Warnings" to avoid fuel spillage and injury.
Fuel return line disconnected at the fuel pressure regulator.
Check the fuel return system(s) for restriction due to blockage, kinking, or pinching.
Disconnect the fuel return line near the fuel tank.
Apply 3-5 psi regulated shop air to the return line at the pressure regulator side.

Does air flow freely through the line?
Yes REPLACE fuel pump assembly. GO to FDS2.
No SERVICE the fuel return line. RECONNECT fuel line. GO to FDS2.

FDS14 CHECK FUEL INJECTOR FLOW AND LEAKAGE
Observe "Caution and Warning" to avoid fuel spillage and injury.
Verify that the fuel injectors flow within specification, using Rotunda Injector Tester 113-00001, SBDS Injector Flow Tester or equivalent.
Is flow rate for individual injectors within specification?
YesCHECK fuel lines for leaks. GO to Group 10 of the Service Manual, then REPEAT Pinpoint Test Step FDS2.
No REPLACE the defective injectors as required. RERUN test FDS14. REPEAT FDS3.

FDS15 CHECK PUMP NOISE
Fuel Pump Noise on 3.0L Taurus Flex Fuel
As 6Conditions that can produce noise are low Methanol fuel blends (less than 30%), high fuel volatility, low fuel level (quarter fill or less), and temperature greater than 75°F. Fuel system noise may become objectionable at start-up or at high engine speed if any of the conditions are present and are considered normal. The noise level can be reduced by taking corrective action. If the noise problem cannot be corrected following this procedure, refer to Group 10 of the Service Manual.

Key off.
Observe the "Cautions and Warnings" to avoid fuel spillage and injury.
Drain fuel tank to less than a quarter tank, then fill tank to at least half with M85 fuel (15% gasoline, 85% methanol).
Start engine and check for excessive fuel pump noise.
Was pump noise reduced by adding M85 fuel?
Yes ADVISE customer accordingly.
NO GO to FDS16.

FDS16 CHECK PUMP SPEEDS
Key off.
Connect DVOM into Inertia Fuel Shutoff (IFS) switch connector.
Start engine and monitor voltage at the IFS.
Is voltage between 12 and 14 volts during crank and initial idle speed, then drops between 7 and 10 volts after a short time?
Yes GO to FDS17.
No Dual voltage system may be damaged. PERFORM Quick Test and repair DTC codes.

FDS17 CHECK PRESSURE DIFFERENCE
Key off.
Observe the "Cautions and Warnings" to avoid fuel spillage and injury.
Install fuel pressure test kit.
Install a second fuel pressure tester on Schrader valve equivalent between fuel pump and the in-line fuel filter, as close to the pump as possible.
Disconnect and plug vacuum hose from fuel pressure regulator.
Start engine and observe fuel pressure difference between gauges.
Key off, compare gauge readings within 10 seconds. Both should read the same, or else one gauge is in error.
Is fuel pressure difference between gauges less than 10 psi?
Yes
REPLACE fuel pump assembly. INSPECT inside of tank for interference, contamination of fuel. SERVICE as necessary.
No REPLACE fuel filter. FILL tank with fresh fuel. REPLACE fuel filter and CHECK system per Group 10 of the Service Manual.

Now I forget if pump pressures are ok!
 

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YMMV, but when putting a rear tank in my 94 F150, i went with a spectra tank from Rockauto with a pump and sending unit already installed. I started having issues with that pump after roughly 500 miles on that tank. (I installed it for a 1500 mile trip to make it so i would stop less for fuel.) Due to the warmer climate and subpar pump, i would have issues with bogging down on acceleration that simply went away if i switched to the front tank.

TL: DR Don't skimp on a fuel pump unless you like changing it.
 

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Discussion Starter #26
UPDATE:

Changed the fuel filter out today and pressure jumped to 35psi. It sits nearly at 40 while it's running, and it actually increases now when you turn the engine off. Truck has been off for 5-10 minutes and the pressure is sitting at 55psi. It drops back down when you turn the key on. There is no change in pressure when removing the vacuum line from the regulator (you can feel the suction on your finger, so it should have adequate vacuum).

I set the timing to 10° and she is running much better, although I think she's still not quite optimal. Idle is somewhat erratic (not lopey... erratic) and she doesn't throw your head back much. With 4.88 gears, this thing should jump off the line with the new motor. I haven't driven much, but so far, no CEL.

I sprayed carb cleaner on each of my vacuum connections and nothing changed, so I don't think I have any major vacuum leaks.

What else should I be checking/adjusting? Do you think my pump is still an issue?
 

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Discussion Starter #27
Well, I want to completely rule out the fuel pump, so I'm dropping the tank tonight. Looks like I finally got lucky, because all 8 nuts turn fairly easily. I'll report back once I've got it replaced.

On another note, anyone know someone in the DFW area that tunes these things? I'd like to take her somewhere and have a pro take a look and make sure it's running like it should be (timing, fuel pressure, sensors, etc). Not sure if the ECM will need a tune, but it might need a little tweaking to get the most out of it. I've already spent a ton, so I'm ok spending a bit more to make sure it's right.
 

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Discussion Starter #28
Further update... got the tank dropped, but my locking ring on top of the pump is pretty rusty. I haven't been able to budge it, and I'm tearing the ears off of it.... it's not looking good!
 

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On another note, anyone know someone in the DFW area that tunes these things? I'd like to take her somewhere and have a pro take a look and make sure it's running like it should be (timing, fuel pressure, sensors, etc).
Try asking the DFW Bronco group on Facebook?

Or ask the Mustang 5.0 guys for recommendations.
 

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Man, I don't think this guy does tuning, but he's a hell of a mechanic. I've used him a few times over the last few years when he was recommended to me. He also rebuilt my transmission himself.

Specialty Unit Remanufacturing

727 N Merrill Ave, Duncanville, TX 75116
(972) 283-3013 Specialty Unit Remanufacturing - Google Search
 

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Problem solved. Just took a little more patience than I had last night. Running better than ever now, but I'm still not convinced that that it's as good as it gets. On to the next issue, which is finding where the oil leak is.... View attachment 154650
I hope you put a new filter "sock" on the bottom of that FDM (Fuel Delivery Module) before you buttoned it all back up.
 

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Discussion Starter #33
Indeed. It wasn't in the picture because I did some test fitting before putting the sock on.
 
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