Ford F150 Pickup. Manual — part 1396

10) Check Low Flow Injectors
Connect a 5-amp fused jumper wire between battery voltage and the low flow injector connector C1289F
terminal "D". While connecting the jumper wire, listen for an audible click from the low flow injector and
the sound of fuel flowing through the low flow injector. If no audible click is heard after connecting the
jumper wire, disconnect the jumper wire, wait five seconds, and repeat the step.

Connect a 5-amp fused jumper wire between the low flow injector connector C1289F terminal "A" and
ground. Listen for an audible click from the low flow injector and the sound of fuel flowing through the
low flow injector. If no audible click is heard after connecting the jumper wire, disconnect the jumper
wire, wait five seconds, and repeat the step.

Connect a 5-amp fused jumper wire between the low flow injector connector C1289F terminal "B" and
ground. Listen for an audible click from the low flow injector and the sound of fuel flowing through the
low flow injector.

If each low flow injector makes an audible click and flows fuel, perform COMPUVALVE CHECK
under QUICK TEST. If concern still exists, replace compuvalve. If each low flow injector does not make
an audible click or does not flow fuel, replace low flow injector(s) in question.

TEST DA: FUEL RAIL TEMPERATURE

Diagnostic Aids

Enter this test only when all steps under QUICK TEST have been successfully completed and engine still does
not start or if directed here from another test or chart. This test is only intended to diagnose:

z

Compuvalve.

z

Harness circuits.

z

Powertrain Control Module (PCM).

Fuel Rail Temperature (FRT) sensor is integral to compuvalve. It is mounted in fuel stream and is supplied a 5-
volt VREF signal from compuvalve. DTCs P0182 and P0183 are set when compuvalve receives a FRT signal
less than -79°F (-62°C) or a signal more than 260°F (127°C). Possible causes for these faults are:

z

FRT sensor circuit open.

"F"

(3)

(1)

See Fig. 26 .

(2)

See Fig. 23 .

(3)

LPG only.

CAUTION: Do not apply battery voltage and ground to the low flow injectors for

more than five seconds while performing the following steps or
excess fuel may accumulate in the intake manifold.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG

z

FRT sensor circuit shorted to VPWR.

z

FRT sensor circuit shorted to GND.

z

Damaged FRT sensor or compuvalve.

z

Engine overheating.

z

Coolant lines or coolant flow through the alternative fuel system.

Testing

1) DTC P0182 Or P0183 Monitor FRTMPAB PID
Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access AFCM and
select FRTMPAB PID from PID/DATA MONITOR & RECORD menu. Record FRTMPAB PID
temperature reading. If FRTMPAB PID is defaulted at 138°F (59°C), leave scan tool connected and go to
next step. If FRTMPAB PID is not defaulted at 138°F (59°C), go to step 3) .

2) Reset FRT Value

Turn ignition off for 5 seconds, then turn ignition on. Access FRTMPAB PID from PID/DATA
MONITOR & RECORD menu and record temperature reading. If FRTMPAB is not defaulted at 138°F
(59°C), leave scan tool connected and go to next step. If FRTMPAB PID is still defaulted at 138°F (59°
C), perform COMPUVALVE CHECK under QUICK TEST. If fault still exists, replace compuvalve.

3) Monitor FRTMPAB PID

Ensure ignition is on. Access FRTMPAB PID from PID/DATA MONITOR & RECORD menu and
record temperature reading. If FRTMPAB PID is between -79 to 260°F (-62 to 127°C), leave scan tool
connected, clear DTCs and go to next step. If FRTMPAB is not between -79 to 260°F (-62 to 127°C),
check for abnormal heat sources around compuvalve. If no abnormal heat sources exist around
compuvalve, perform COMPUVALVE CHECK under QUICK TEST. If fault still exists, replace
compuvalve.

4) Retrieve DTCs

Start engine and warm to normal operating temperature. Turn ignition on. Perform AFCM
CONTINUOUS MEMORY SELF-TEST . If DTC P0182 or P0183 is present, perform
COMPUVALVE CHECK under QUICK TEST. If fault still exists, replace compuvalve. If DTCs P0182

NOTE:

During bi-fuel diagnostics, intermittent failures are possible. Perform wiggle
test and tap lightly on relays during testing. Ensure vehicle has LPG before
continuing with diagnostics.

NOTE:

If DTCs P0182 and P0183 are set and Fuel Rail Temperature (FRT) sensor
is continually shorted, scan tool will show a default value of 138°F (59°C).
Turning ignition off for more than 5 seconds should reinstate FRT sensor
if it is functioning correctly and will display a sensor reading of actual
FRT.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG

or P0183 are not present, system is operating normally at this time. See INTERMITTENTS in
TROUBLE SHOOTING - NO CODES - BI-FUEL - GASOLINE/LPG article.

TEST DB: MAP/BARO SENSOR

Diagnostic Aids

Enter this test only when all steps under QUICK TEST have been successfully completed and engine still does
not start or if directed here from another test or chart. This test is only intended to diagnose compuvalve
MAP/BARO circuits.

Manifold Absolute Pressure/Barometric pressure (MAP/BARO) sensor is internal to compuvalve. DTCs P0107
and P0108 are set when compuvalve receives an excessively high or low voltage, a high voltage under light
load driving conditions, or a low voltage under heavy driving conditions through internal MAP/BARO
circuitry. Possible causes for these faults are:

z

Vacuum hoses between intake manifold and compuvalve are disconnected or clogged.

z

Faulty compuvalve.

z

MAP sensor elbow could be inserted too far, restricting MAP signal to compuvalve.

Testing

1) Check MAP PID

Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access AFCM and
select MAP PID from PID/DATA MONITOR & RECORD menu. If MAP PID value reads about local
barometric pressure, leave scan tool connected and go to next step. If MAP PID value does not read about
local barometric pressure, perform COMPUVALVE CHECK under QUICK TEST. If fault still exists,
replace compuvalve.

2) Check MAP/BARO Sensor

Start engine and allow to idle running on gas. Using scan tool, access AFCM and select MAP PID from
PID/DATA MONITOR & RECORD menu. Connect hand-held vacuum pump to MAP inlet on
compuvalve. Apply low, and then high vacuum to MAP sensor. If MAP PID reading changes from
atmospheric pressure with no vacuum applied to a low value with high vacuum applied, go to next step. If
MAP PID reading does not change from atmospheric pressure with no vacuum applied to a low value
with high vacuum applied, perform COMPUVALVE CHECK under QUICK TEST. If fault still exists,
replace compuvalve.

3) Check Vacuum Source To Compuvalve

NOTE:

During bi-fuel diagnostics, intermittent failures are possible. Perform wiggle
test and tap lightly on relays during testing. Ensure vehicle has LPG before
continuing with diagnostics.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG

Connect vacuum gauge to MAP vacuum supply line. Start engine and allow to idle. If vacuum gauge
reads manifold vacuum, perform COMPUVALVE CHECK under QUICK TEST. If fault still exists,
replace compuvalve. If vacuum gauge does not read manifold vacuum, repair vacuum supply line. Clear
DTCs and retest.

TEST DC: FUEL RAIL PRESSURE

Diagnostic Aids

Enter this test only when all steps under QUICK TEST have been successfully completed and engine still does
not start or if directed here from another test or chart. This test is only intended to diagnose:

z

Fuel rail pressure circuit.

z

Compuvalve.

Fuel Absolute Pressure (FAP) sensor is internal to compuvalve. DTCs P0192 and P0193 are set when
compuvalve receives an extremely high or low pressure reading of more than 60 psi, or less than 4.9 psi from
FAP. The FAP is monitored to make sure the ALT fuel regulator is functioning correctly. Possible causes for
these faults are:

z

FAP sensor circuit open, or shorted to GND or VPWR.

z

Damaged FAP sensor or compuvalve.

z

Inoperative regulator.

z

Inoperative vaporizer.

Testing

1) Check FRPREAB PID
Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool,
access AFCM and select FRPREAB PID from PID/DATA MONITOR & RECORD menu. If FRPREAB
PID reading is less than 6 psi, perform COMPUVALVE CHECK under QUICK TEST. If fault still
exists, replace compuvalve. If FRPREAB PID reading is more than 60 psi, go to next step. If FRPREAB
PID reading is 6-60 psi, system is operating normally at this time. See INTERMITTENTS in
TROUBLE SHOOTING - NO CODES - BI-FUEL - GASOLINE/LPG article.

2) Check FRPREAB PID Change

Turn ignition off. Release ALT fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE

NOTE:

During bi-fuel diagnostics, intermittent failures are possible. Perform wiggle
test and tap lightly on relays during testing. Ensure vehicle has LPG before
continuing with diagnostics.

WARNING:

High FRPREAB value indicates high pressure in system. Use
caution when working with components in system.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG