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5.4 l 2v P071 & P0174 high lean long term fuel trims bank 1 & 2, Low power under load

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5.4 l 2v P071 & P0174 high lean long term fuel trims bank 1 & 2, Low power under load

 
  #1  
Old 07-06-2019, 02:34 PM
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5.4 l 2v P071 & P0174 high lean long term fuel trims bank 1 & 2, Low power under load

I own a 1998 E350 5.4 l 2v van. It started throwing the p071 & p0174 lean long term fuel trim codes banks 1 & 2 after I replaced the DPFE pressure sensor and lines for throwing another code. Hopefully, they are not related.

I get the code under load only while driving up grades. Long term fuel trims on bank 1 and 2 are 21% and higher. I recorded this using OBD Fusion. The van feels sluggish while driving up grades. It used to climb the same grade easily in 3rd gear. It now shifts into second gear on the same grade.

I have not checked the fuel pressure as I don't have the gauge and am looking for a decent gauge for this test.

The MAF sensor was replaced in January by the previous owner. However, it's still fair game for known suspect(s). I cleaned the MAF yesterday. I plan on removing it today and cleaning it outside the vehicle. My MAF gauge reads .85 lbs/min. Anyone know what it's supposed to read?

i checked for obvious vacuum leaks with propane. The PCV and hose is new.

I drove a 6.0 diesel van before this, so I cannot compare the power or throttle response. After driving the diesel for years, everything seems sluggish.
 
  #2  
Old 07-07-2019, 12:50 AM
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Originally Posted by coolfeet View Post
.... I have not checked the fuel pressure as I don't have the gauge and am looking for a decent gauge for this test. ....
Harbor Freight has a basic fuel pressure gauge, 62623, for $20, less with a 20% off coupon.
I've used it several times, works fine.
It's listed as a "Fuel Injection Pump Tester" instead of fuel pressure test gauge.
It hooks up to the fuel rail test port valve.
 
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Old 07-07-2019, 01:04 AM
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Originally Posted by R&T Babich View Post
Harbor Freight has a basic fuel pressure gauge, 62623, for $20, less with a 20% off coupon.
I've used it several times, works fine.
It's listed as a "Fuel Injection Pump Tester" instead of fuel pressure test gauge.
It hooks up to the fuel rail test port valve.
Thanks for the tip. Harbor Freight is 10 minutes from my place. I need to systematically check all suspected problems before replacing parts.
 
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Old 07-07-2019, 04:02 AM
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Do keep in mind there's a procedure for proper FP testing---its not just hooking the gauge to the rail and staring the engine. You'll want to test the fuel pressure regulator too.

If someone doesn't have the printable PDF view of that procedure ready to share I can dig mine from a 2000 E250 that I could email to you CoolFeet. It might take a day or so please keep that in mind---I'd not want to delay your testing.
 
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Old 07-07-2019, 10:56 AM
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JWA, I have time on my side for testing everything. We do not have any big camping trips planned. Dig up the testing procedures at your leisure. It will be helpful to many folks here. I believe there are Key on key off tests.

Sorry to hear about your COP inserts going bad! Plastic and aluminum are not the best combinations. I hope you don't have to remove the manifolds.
 
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Old 07-07-2019, 10:20 PM
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I replaced the fuel filter in May with a Motorcraft. The van started throwing codes about 1000 miles into a 3500-mile trip. I thought I may have filled the tank with bad gasoline. Most of the time I filled the tank at Costco, Chevron, or Sinclair. The suspect fuel was at a small filling station in Utah with brand name gasoline. I am thinking of changing the fuel filter to eliminate it as a suspect.

My main Ford MasterTech diesel mechanic said he will take the vehicle for repair if I cannot figure it out. I will be embarrassed if the problem is the fuel filter. On the other hand, he would be pleased and paid well. He is an experienced gas and Powerstroke diesel tech.

I drove the van over 2 mountain passes today and it felt sluggish. Normally, the van will downshift into 3rd gear and easily climb the passes. Today, the van downshifted into second gear.
 
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Old 07-09-2019, 06:26 PM
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I have an exhaust leak on bank 1. Stud broke.

Could this cause bank 1 and 2 LTF trim to be lean?
 
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Old 07-10-2019, 05:05 AM
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Originally Posted by coolfeet View Post
I have an exhaust leak on bank 1. Stud broke.

Could this cause bank 1 and 2 LTF trim to be lean?
I have much the same condition (just one stud broken) on my '03 5.4 with just over 285K miles---LTFT's are fine even with that small leak. I'd have to say that leak doesn't seem to affect LTFT's.

Also I have the diagnosis testing for fuel pressure I mentioned earlier--should be able to copy and print this. Also have it in a .doc format I could email you---if that's needed PM me.

HTH

2000 PCED OBD II
SECTION 5: Pinpoint Tests
Procedure revision date: 08/01/2002
HC: Fuel Delivery System

HC1 CHECK SYSTEM INTEGRITY

  • Visually inspect the complete fuel delivery system for damage; including fuel lines, connections, relays, fuel tank, fuel pump, fuel pressure regulator, fuel pulse damper and fuel injector areas for leaks, looseness, cracks, kinks, pinching, or abrasion caused by a collision or mishandling.
  • Visually inspect electrical harness and connectors for loose pins, corrosion, abrasion, or other damage from collision or mishandling.
  • Check electrical connectors for proper mating.
  • Verify vehicle has followed maintenance schedule.
  • Verify inertia fuel shutoff (IFS) switch is set.
  • Verify battery is fully charged (12.5 volts or greater).
  • Verify electrical/fuse integrity.
  • Verify fuel level in the tank is sufficient.
Are any concerns present?
YesNo

REPAIR as necessary.GO to HC2 .

HC2 CHECK VOLTAGE AT FUEL PUMP HARNESS CONNECTOR

  • Connect battery charger.
  • Verify IFS switch state. Follow the IFS switch reset procedure at the beginning of this pinpoint test.
  • Disconnect the fuel pump harness connector at the fuel pump.
  • Key on, engine off.
  • Connect a digital multimeter between the fuel pump power circuit and fuel pump ground circuit at the fuel pump harness connector (refer to the Wiring Diagram Manual for correct pin location).
  • Access Output Test Mode (refer to Section 2 ) and turn on the fuel pump circuit and monitor the voltage reading.
Was the voltage greater than 12.5 volts?
YesNo

KEY OFF. EXIT Output Test Mode. GO to HC3 .KEY OFF. FOR vehicles with electronic returnless fuel systems:GO to KB70 .

ALL others: CHECK for opens and shorts in the fuel pump power and ground circuits.

HC3 CHECK FUEL FILTER FOR PROPER MAINTENANCE

  • Locate and inspect the vehicle maintenance schedule and fuel filter. Check for last repair date.
Was the fuel filter replaced within the last 48,280 km/30,000 miles?
YesNo

GO to HC4 .REPLACE fuel filter. GO to HC4 .

HC4 CHECK FUEL PRESSURE

[img]VY2~us~en~file=ani_caut.gif~gen~ref.gif WARNING: BEFORE SERVICING OR REPLACING ANY COMPONENTS IN THE FUEL SYSTEM, REDUCE THE POSSIBILITY OF INJURY OR FIRE BY FOLLOWING DIRECTIONS IN FUEL SYSTEM CAUTION, HANDLING AND WARNING AT THE BEGINNING OF THIS PINPOINT TEST.
  • Install fuel pressure tester.
  • Release fuel pressure.
  • Key on, engine off.
  • Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure. (GO to Pinpoint Test HC to refer to the Fuel Delivery System Test Information/Specification Chart.)Note: The fuel pump will only operate for approximately 8 seconds when Output Test Mode is selected and activated.
Is the fuel pressure within the specified pressure range as stated in the Fuel Delivery System Test Information/ Specification Chart?
YesNo

KEY OFF. For Electronic Returnless Fuel Systems : Concern is elsewhere. RETURN to Section 3 , Symptom Charts for further direction.

KEY OFF. For Mechanical Returnless Fuel Systems :GO to HC12 .

All others: GO to HC5 .KEY OFF. For Mechanical Returnless Fuel System with fuel pressure greater that 448 kPa (65 psi). REPLACE fuel pressure regulator in fuel tank.

For Mechanical Returnless Fuel System with fuel pressure less than 310 kPa (45 psi): GO to HC6 .

For Electronic Returnless Fuel Systems with fuel pressure less than 207 kPa (30 psi). GO to HC13 .

For Electronic Returnless Fuel Systems with fuel pressure greater than 448 kPa (65 psi). RERUN Quick Test. Other DTC's should be present if fuel pressure is out of range..

All others:

Fuel pressure greater than 280 kPa (40 psi) (Cougar 415 kPa (60 psi) on returnable fuel systems , GO to HC10 .

Fuel pressure less than 240 kPa (35 psi) (Cougar 310 kPa (45 psi) on returnable fuel systems , GO to HC13 .


HC5 CHECK FUEL PRESSURE LEAKDOWN

  • Observe Warning, Caution and Notes.
  • Fuel pressure tester installed.
  • Key on, engine off.
  • Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure.
  • Key off.
  • Verify fuel pressure remains within 34 kPa (5 psi) of the maximum fuel pressure for 1 minute after the fuel pump is turned off.
Does the fuel pressure remain within 34 kPa (5 psi)?
YesNo

GO to HC7 .GO to HC6 .

HC6 CHECK PRESSURE REGULATOR AND PULSE DAMPER DIAPHRAGM

  • Fuel pressure tester installed.
  • Start engine and run engine for 10 seconds.
  • Key off, wait 10 seconds.
  • Start engine and run engine for 10 seconds.
  • Key off, remove vacuum hose from fuel pressure regulator or pulse damper port.
  • Inspect for fuel in the vacuum hose or regulator port or pulse damper.
Is fuel present in the vacuum hose and regulator or pulse damper port?
YesNo

REPLACE fuel pressure regulator.

For Mechanical Returnless Fuel System:

Replace pulse damper.GO to HC12 .

HC7 CHECK FUEL PRESSURE, ENGINE RUNNING

  • Fuel pressure tester installed.
  • Disconnect vacuum hose at the fuel pressure regulator and plug it.
  • Drive vehicle with heavy accelerations while observing fuel pressure gauge reading.
Does fuel pressure reading hold steady within 21 kPa (3 psi) during test?
YesNo

GO to HC8 .GO to HC13 .

HC8 CHECK FUEL PRESSURE REGULATOR RESPONSE

  • Fuel pressure tester installed.
  • Install vacuum gauge to intake manifold.
  • Start engine and observe both gauges.
  • Accelerate and decelerate engine speed to vary vacuum gauge reading.
Does the fuel pressure gauge reading increase as vacuum gauge reading decreases or decrease as vacuum gauge reading increases?
YesNo

Concern is elsewhere. RETURN to Section 3 , Symptom Charts for further direction.GO to HC9 .

HC9 CHECK VACUUM SUPPLY

  • Fuel pressure tester installed.
  • Vacuum hose disconnected and plugged at the fuel pressure regulator.
  • Install a hand held vacuum pump to the fuel pressure regulator.
  • Start engine, remain at idle.
  • Observe fuel pressure while applying vacuum.
Does the fuel pressure change as the vacuum changes?
YesNo

REPAIR vacuum source.REPLACE fuel pressure regulator.

HC10 CHECK FOR RESTRICTED FUEL RETURN LINE

  • Fuel pressure tester installed.
  • Remove fuel return line at the fuel rail and connect a short hose from the fuel rail to a measure container of at least 1.1 liter (1.0 quart) capacity.
  • Key on, engine off.
  • Access Output Test Mode and run the fuel pump to obtain maximum fuel flow (one cycle of the fuel pump is all that is required).
  • Record fuel pressure and observe if fuel is being returned to the measuring container.
Is fuel pressure between (Contour/Mystique, 2.5L Cougar 310 and 415 kPa (45 and 60 psi) or 240 and 280 kPa (35 and 40 psi) on all others and is fuel returning to the container?
YesNo

KEY OFF. GO to HC11 .KEY OFF. Fuel pressure greater than 415 kPa (60 psi) on Contour/Mystique, 2.5L Cougar or all others 290 kPa (45 psi). REPLACE fuel pressure regulator.

HC11 CHECK FUEL RETURN SYSTEM

  • Observe Warning, Caution and Handling at the beginning of this pinpoint test.
  • Disconnect fuel return line at the fuel rail.
  • Disconnect fuel return line at the fuel pump.
  • Check the fuel return line for restrictions due to blockage, kinking or pinching.
  • Apply 21 to 34 kPa (3 to 5 psi) regulated shop air to the return line pressure.
Does air flow freely through the line?
YesNo

REPLACE the fuel pump module.REPAIR the fuel return line.

HC12 CHECK FUEL INJECTOR FLOW AND LEAKAGE

  • Observe Warning, Caution and Handling at the beginning of this pinpoint test.
  • Check injectors for leakage and flow rate using Injector Flow Tester.
Are test results satisfactory?
YesNo

For symptoms without DTCs and Electronic/Mechanical Returnless Fuel Systems: RETURN to Section 3 , Symptom Charts for further direction.

All others: VERIFY no other leak exists. REPLACE fuel pump module.REPLACE the failed fuel injector(s).

HC13 CHECK FUEL SUPPLY LINE FOR RESTRICTION

  • Observe Warning, Cautions and Handling at the beginning of this pinpoint test.
  • Disconnect fuel supply line at the fuel rail.
  • Disconnect fuel supply line at the fuel pump.
  • Check the fuel supply line for restrictions due to blockage, kinking, or pinching.
  • Apply 21 to 34 kPa (3 to 5 psi) regulated shop air pressure to the supply line.
Does air flow freely through the line?
YesNo

Air flows freely. REPLACE fuel pump module.REPAIR cause of restriction.






















 
  #9  
Old 07-10-2019, 08:18 AM
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Thanks for this procedure for checking the fuel delivery system. I will get out my manuals and check this weekend.

How loud is your manifold leak?
 
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Old 07-10-2019, 01:00 PM
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How do I access the Access Output Test Mode

[img]VY2~us~en~file=ani_caut.gif~gen~ref.gif WARNING: BEFORE SERVICING OR REPLACING ANY COMPONENTS IN THE FUEL SYSTEM, REDUCE THE POSSIBILITY OF INJURY OR FIRE BY FOLLOWING DIRECTIONS IN FUEL SYSTEM CAUTION, HANDLING AND WARNING AT THE BEGINNING OF THIS PINPOINT TEST.
  • Install fuel pressure tester.
  • Release fuel pressure.
  • Key on, engine off.
  • Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure. (GO to Pinpoint Test HC to refer to the Fuel Delivery System Test Information/Specification Chart.)Note: The fuel pump will only operate for approximately 8 seconds when Output Test Mode is selected and activated.
Is the fuel pressure within the specified pressure range as stated in the Fuel Delivery System Test Information/ Specification Chart?
YesNo"
 
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Old 07-10-2019, 02:40 PM
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According to this fuel trim video posted by JWA on another thread, my problem is either MAF or a fuel delivery problem. When the LTF trim goes up when under a load and then comes down again at idle, it's probably MAF or the fuel pump. Further investigation needed.

 
  #12  
Old 07-11-2019, 05:28 AM
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Originally Posted by coolfeet View Post

How loud is your manifold leak?
I can hear it as a "louder" puffing noise--listening from outside the van. Inside its not noticeable, not over the typical road noise anyway.

I think I have just one stud broken on the #2 cylinder, bottom of the exhaust manifold. I "hope" this particular van will be gone by the end of this year so for now it's not something I'll address.
 
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Old 07-11-2019, 08:23 AM
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How To Test The Ford MAF Sensor (4.2L, 4.6L, 5.4L)

I found a simple procedure on How To Test The Ford MAF Sensor (4.2L, 4.6L, 5.4L). I have a multimeter. I am hopeful that the MAF is bad. If the MAF is good, then it's probably the fuel pump.

My buddy had a clogged fuel screen on his E350 diesel van. The screen is located in the fuel tank. Probably the same place that Ford puts the fuel pump for the 5.4. He cut a hole through the floor to gain access to the screen for cleaning. Next, he made a cover for the hole to access it every time the screen needed cleaning. Genius! If my fuel pump is bad, then I will perform surgery on the floor. I don't want to pay $500 for removal of the fuel tank.
 
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Old 07-11-2019, 10:24 AM
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Much like an SMB or adventure vehicle I have too much built in over top of that area. Even so I'd never cut the floor away like that---it opens that area up to rust being formed and spreading rapidly.

When my fuel pump failed I paid for the new Motorcraft part, new fuel filter and two new OEM tank straps. As luck would have it one of the straps had worn a small hole that was relatively easy to fix. Had I not done this no telling how long the undetected leak would have remained plugged by the tank strap insulators.

Yeah dropping the tank is not the cheapest way to go but I think its the best route for higher reliability.

Motorcraft fuel pumps can be found on eBay for just about $100 or more less than I paid at the dealer. I didn't have the luxury of waiting time so had to spring a full $430---Ouch!
 
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Old 07-11-2019, 12:36 PM
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Originally Posted by coolfeet View Post
I found a simple procedure on How To Test The Ford MAF Sensor (4.2L, 4.6L, 5.4L). I have a multimeter. I am hopeful that the MAF is bad. If the MAF is good, then it's probably the fuel pump. ....
Have you checked out the fuel pump relay?
If the relay contacts are badly pitted the power the pump receives can be be reduced.
 

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