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Discussion Starter #1
Im new to this site and in need of some advice,, i recently bought a rock crawler that is a 90 model Bronco with a Bronco II body that would not start due to build up at the an fitting on the fuel cell, drained the tank cleaned everything out, replaced fuel line from tank 2 fuel rail and fuel pump with a new filter and a new regulator with no results. My next step I did was take all the injectors out and checked in with a tester to see if they had good spray with carb cleaner and all looked in good shape and pulsed fine,, I have checked the timing and it is at 10 degrees btdc and have fixed any vacuum leaks on the motor so where is the next thing to look at,,,would the distributor pickup cause fuel pressure to go low????
 

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No on the pickup causing fuel pressure issues. One these trucks (the stock bronco stuff) the fuel system is basically independant from the ecm, with only the ecm turning on the fuel pump relay to turn the pump on.
The fuel pressure is low, I will agree with that. You should be able to have full pressure even with truck off and fuel pumps running, with the harness for the relay jumped, or possibly just turned on. Not sure what your working with. The fuel pressure should be 38-40 pending if the vacuum line is connected or not.

Do you know what the current fuel pump setup is??? 90 likely had a pump in the tank, and a pump in the line on rail. It is possible one of those has failed, or is not installed. You may have something completely different as well, running with a fuel cell.
 

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Yo @Take-it-to-the-top 416
Welcome!
Some of the Following by Ford with my editing;
"...When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link attached to the starter solenoid (battery side). From the fuse line, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM)."

➡Inspect wiring at IFS switch & IFS switch itself for loose mounting, poor wire connection, defective switch.
152749

Location in Full Body Diagram in a 90 by Seattle FSB

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

➡After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."
➡Does ignition key feel loose in key cylinder? Test the mechanical operation by rotating the Key through all positions of the ignition switch. The movement should feel smooth with no sticking or binding. The key should return from the START position back to the ON position without assistance (spring return). If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ensure switch is securely mounted

➡Accessories that fail to operate with the key in RUN, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.*

Ignition Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in 87-91 @ Started just fine, AAAHHHHH!! It won't turn off!!!
➡ Any misfiring?
➡Or is check engine light on or self test reveal codes?
■●■

Here is Ford's fuel system tests in full. I tried to post just the salient tests, however my screen jumps around while I try to copy just what you need, but had to stop.

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."
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.

System Diagnosis
152748

Note:
Grounding the FP lead at the DLC will allow the pump to run continuously with the ignition switch on.
Is fuel pressure within specification?
Yes GO to FDS3.
No, 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.
Connect a jumper to the FP lead of the DLC.
Key on, engine off.
Ground the test lead using the jumper wire to run the fuel pump.
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.
On dual tank system, perform test for both tanks.
Does fuel pressure remain within 5 psi for 1 minute after the test lead is ungrounded?
Yes GO to FDS5.
No GO to FDS4.

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.
On Type 2 (Dual Tank System) perform test for both tanks.
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 For 3.0L Taurus Flex Fuel and Mark VIII:
GO to FDS9.
All others:GO to Group 10 of the Service Manual for additional Description, Diagnosis and Testing.
Miesk5 Note; screen is jumping much more now, so I have to stop inserting ➡
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.
Ground FP lead as in step FDS2.
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 For type 2: CHECK both pumps. If both are low, CHECK voltage at both pumps before replacing pumps.
All others: 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.
Ground FP lead as in step FDS2.
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 For type 2: GO to FDS12.
All others: 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.
On Type 2 system block return line at fuel tank on one tank and test through remaining line. Perform test for both tanks.
Does air flow freely through the line?
Yes For Type 2:
GO to Group 10 of the Service Manual for Description, Diagnosis and Testing of the FDM System.
For Type 1:
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

Conditions 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."

Wlll bbl, need to do some work
 

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Discussion Starter #7
No on the pickup causing fuel pressure issues. One these trucks (the stock bronco stuff) the fuel system is basically independant from the ecm, with only the ecm turning on the fuel pump relay to turn the pump on.
The fuel pressure is low, I will agree with that. You should be able to have full pressure even with truck off and fuel pumps running, with the harness for the relay jumped, or possibly just turned on. Not sure what your working with. The fuel pressure should be 38-40 pending if the vacuum line is connected or not.

Do you know what the current fuel pump setup is??? 90 likely had a pump in the tank, and a pump in the line on rail. It is possible one of those has failed, or is not installed. You may have something completely different as well, running with a fuel cell.
With key on engine off my fuel pressure gauge is reading 36 and is fine there at idle it's when you throttle it up pressure goes down like there's a clog in the system but all hoses are new, I do not have the stock tank I'm running an aluminum fuel cell with only fuel pump on the frame about drivers door.
 

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Registered
Joined
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8 Posts
Discussion Starter #8
Yo @Take-it-to-the-top 416
Welcome!
Some of the Following by Ford with my editing;
"...When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link attached to the starter solenoid (battery side). From the fuse line, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM)."

➡Inspect wiring at IFS switch & IFS switch itself for loose mounting, poor wire connection, defective switch.
View attachment 152749
Location in Full Body Diagram in a 90 by Seattle FSB

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

➡After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."
➡Does ignition key feel loose in key cylinder? Test the mechanical operation by rotating the Key through all positions of the ignition switch. The movement should feel smooth with no sticking or binding. The key should return from the START position back to the ON position without assistance (spring return). If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ensure switch is securely mounted

➡Accessories that fail to operate with the key in RUN, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.*

Ignition Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in 87-91 @ Started just fine, AAAHHHHH!! It won't turn off!!!
➡ Any misfiring?
➡Or is check engine light on or self test reveal codes?
■●■

Here is Ford's fuel system tests in full. I tried to post just the salient tests, however my screen jumps around while I try to copy just what you need, but had to stop.

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."
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.

System Diagnosis
View attachment 152748
Note:
Grounding the FP lead at the DLC will allow the pump to run continuously with the ignition switch on.
Is fuel pressure within specification?
Yes GO to FDS3.
No, 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.
Connect a jumper to the FP lead of the DLC.
Key on, engine off.
Ground the test lead using the jumper wire to run the fuel pump.
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.
On dual tank system, perform test for both tanks.
Does fuel pressure remain within 5 psi for 1 minute after the test lead is ungrounded?
Yes GO to FDS5.
No GO to FDS4.

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.
On Type 2 (Dual Tank System) perform test for both tanks.
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 For 3.0L Taurus Flex Fuel and Mark VIII:
GO to FDS9.
All others:GO to Group 10 of the Service Manual for additional Description, Diagnosis and Testing.
Miesk5 Note; screen is jumping much more now, so I have to stop inserting ➡
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.
Ground FP lead as in step FDS2.
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 For type 2: CHECK both pumps. If both are low, CHECK voltage at both pumps before replacing pumps.
All others: 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.
Ground FP lead as in step FDS2.
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 For type 2: GO to FDS12.
All others: 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.
On Type 2 system block return line at fuel tank on one tank and test through remaining line. Perform test for both tanks.
Does air flow freely through the line?
Yes For Type 2:
GO to Group 10 of the Service Manual for Description, Diagnosis and Testing of the FDM System.
For Type 1:
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

Conditions 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."

Wlll bbl, need to do some work
Yo @Take-it-to-the-top 416
Welcome!
Some of the Following by Ford with my editing;
"...When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link attached to the starter solenoid (battery side). From the fuse line, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM)."

➡Inspect wiring at IFS switch & IFS switch itself for loose mounting, poor wire connection, defective switch.
View attachment 152749
Location in Full Body Diagram in a 90 by Seattle FSB

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

➡After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."
➡Does ignition key feel loose in key cylinder? Test the mechanical operation by rotating the Key through all positions of the ignition switch. The movement should feel smooth with no sticking or binding. The key should return from the START position back to the ON position without assistance (spring return). If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ensure switch is securely mounted

➡Accessories that fail to operate with the key in RUN, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.*

Ignition Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in 87-91 @ Started just fine, AAAHHHHH!! It won't turn off!!!
➡ Any misfiring?
➡Or is check engine light on or self test reveal codes?
■●■

Here is Ford's fuel system tests in full. I tried to post just the salient tests, however my screen jumps around while I try to copy just what you need, but had to stop.

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."
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.

System Diagnosis
View attachment 152748
Note:
Grounding the FP lead at the DLC will allow the pump to run continuously with the ignition switch on.
Is fuel pressure within specification?
Yes GO to FDS3.
No, 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.
Connect a jumper to the FP lead of the DLC.
Key on, engine off.
Ground the test lead using the jumper wire to run the fuel pump.
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.
On dual tank system, perform test for both tanks.
Does fuel pressure remain within 5 psi for 1 minute after the test lead is ungrounded?
Yes GO to FDS5.
No GO to FDS4.

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.
On Type 2 (Dual Tank System) perform test for both tanks.
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 For 3.0L Taurus Flex Fuel and Mark VIII:
GO to FDS9.
All others:GO to Group 10 of the Service Manual for additional Description, Diagnosis and Testing.
Miesk5 Note; screen is jumping much more now, so I have to stop inserting ➡
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.
Ground FP lead as in step FDS2.
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 For type 2: CHECK both pumps. If both are low, CHECK voltage at both pumps before replacing pumps.
All others: 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.
Ground FP lead as in step FDS2.
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 For type 2: GO to FDS12.
All others: 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.
On Type 2 system block return line at fuel tank on one tank and test through remaining line. Perform test for both tanks.
Does air flow freely through the line?
Yes For Type 2:
GO to Group 10 of the Service Manual for Description, Diagnosis and Testing of the FDM System.
For Type 1:
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

Conditions 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."

Wlll bbl, need to do some work
Thanks for the ford diag procedure, i will check the flow of return line as mentioned and see how much i have.
 

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How far from the fuel cell is the fuel pump? Is the cell higher or even with the pump? What brand of pump? You may have too much suction draw causing the pump to starve.
 

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Discussion Starter #10
How far from the fuel cell is the fuel pump? Is the cell higher or even with the pump? What brand of pump? You may have too much suction draw causing the pump to starve.
Pump is at drivers door and fuel cell is sitting where cargo area would be and is higher than pump.
 

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Discussion Starter #11
PROBLEM SOLVED,THANKS FOR THE HELP. first thing i replaced was the pump and regulator then fuel lines so i switched back the old pump and fuel pressure rises when throttle is applied,, ford has 2 pumps so the new i bought would not keep volume at higher rpms.
 
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