Ford Falcon. Manual — part 184

303-04c-24

Single Fuel LPG

303-04c-24

DIAGNOSIS AND TESTING (Continued)

Relief Valve

Condition

Source

Action

Leaking (Note:This is normal if tank

Foreign matter caught between seat.

Replace relief valve.

pressure is above 2.5 MPa)

Defective seat.

Replace relief valve.

Inadequate spring tension.

Replace relief valve.

LPG Gauge & Sender Unit

Condition

Source

Action

Inaccurate tank reading.

Defective sender.

Replace sender.

Misaligned gearing.

Replace float arm.

Remains at empty.

Defective sender.

Replace sender.

Defective float arm.

Replace float arm.

Wiring fault.

Check and rectify wiring.

Leaking gas.

Defective gasket.

Replace gasket.

Dash-mounted fuel gauge

Condition

Source

Action

No indication.

Empty fuel tank.

Refill tank.

Broken/disconnected wire.

Check wiring.

Grounded wire from sender.

Check wiring.

Sender not earthed.

Check earthing connection & PCM

Sender defective.

Replace sender.

Erratic reading.

Loose connection.

Tighten connection.

Defective sender.

Replace sender.

Reads full at all times.

Short in wiring.

Check wiring.

Defective sender.

Replace sender.

Inaccurate reading.

Defective sender or gauge.

Replace defective part.

Receiver incompatible with sender.

Check resistance in ohms.

Functional Diagnosis

Condition

Probable Cause & Rectification

Hints / Cautions

Driveability issues such Replace Ram-Air Balance Tube if

A small crack or hole in the Balance

as stalling, roughness

damaged. Refit if simply dislodged.

Tube, often difficult to see, will cause a

of operation, flat spots,

driveability issue.

hesitations, surges, etc.

Remove & clear Ram-Air Balance Tube

Ensure care is taken not to damage

of water, grass, etc. Refit.

Balance Tube during this process (see

above).

Replace Air Filter if dirty. Ensure Air

A dirty Air Filter will cause driveability

Cleaner & Springs are installed correctly. issues. Always reset KAM after it is

replaced.

Clear contaminant/blockage from idle jet. The idle jet plays an important role

Refit.

throughout the driving range – not just

at idle.

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303-04c-25

Single Fuel LPG

303-04c-25

DIAGNOSIS AND TESTING (Continued)

Condition

Probable Cause & Rectification

Hints / Cautions

Inspect & clean the mesh within the

This requires high pressure liquid LPG

Filter/Lock-off at Converter. Refit.

work and must, therefore, be conducted

by a registered technician.

Check for leaks in the Intake System

A small vacuum leak from the intake

between the Air Filter Element and the

Manifold or any vacuum assisted

Gas-Air Mixer, Intake Manifold or PCV

component will lean out the air/fuel

System. Rectify all leaks.

mixture causing driveability issues.

Check condition of PCV Valve. Replace if If the PCV Valve is broken, check the

damaged or faulty.

Valve Cover for fragments. They will be

held within a baffle.

If insufficient supply of LPG is making it

Prior to working on components

to the converter, ensure both Manual

associated with high pressure liquid

Isolating Valves on each LPG Tank

LPG, always run the vehicle with the

Service Valve are fully open and the

Manual Isolating Valve closed until the

condition and security of steel Bundy

engine stalls to ensure no LPG remains

tubes is satisfactory. Rectify any damage after the Service Valve.

or leaks. If there is no fault found

externally, the Service Valve and its

Strainer or a blockage within the Bundy

tubes could be the problem. Replace the

Service Valve or clear the blockage as

required.
Drain contaminant from converter whilst

Draining a hot converter will allow those

still hot from recent LPG operation. Refit

contaminants that solidify when cool to

both drain plugs.

be drained as well. However,

precautions must be taken against

burns.

Check Secondary Chamber within the

Gently pushing on the metal plate in the

Converter retains pressure for at least 10 centre of the Secondary Diaphragm

minutes after recent LPG operation. If

through the hole in the Converter

not, recondition or replace converter.

outboard shell should result in an

Note: Converter-related warranty claims

audible release of pressure. The metal

require a Ford Prior Approval No. to be

plate should move in without

issued.

notchiness, indicating that the pin

behind it isn’t sticking.

Contamination, damage or

Do not Key On with the Stepper Motor

electrical/mechanical fault within Stepper removed from its mounting body. It will

Motor leading to Stepper Motor seizure.

reset which involves full extension and

Replace Stepper Motor.

subsequent loss of the Pintle.

Wiring or connector damage or fault

The NGS has a built in Self Test to

between Stepper Motor and PCM leading check fuel control. Stepper Motor

to Stepper Motor seizure, reversal of

position can also be monitored - most

direction or stutter. Rectify wiring or

usefully with HEGO voltage.

connector problem.
PCM not providing correct signals to

Swapping PCMs to check for

Stepper Motor. Replace PCM.

functionality where PATS/BETS is

active cannot be done.

Check Ignition System components for

A slight ignition breakdown under load is

function and security.

significant with LPG.

Backfiring

Rectify problem with Ignition System.

A lean mixture increases the likelihood

Check spark plug specification, gap and

of a backfire with a poor Ignition

condition. Ensure COILS are in good

System, but is not the true cause of the

condition.

problem.

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303-04c-26

Single Fuel LPG

303-04c-26

DIAGNOSIS AND TESTING (Continued)

Condition

Probable Cause & Rectification

Hints / Cautions

Water comes out of

Repair or replace Converter. Note:

Cooling System maintenance is

vapour hose or

Converter - related warranty claims

extremely important in all

converter drain plugs

require a Ford Prior Approval No. to be

Converter-based LPG systems. Check

issued. Rectify Cooling System fault or

engine doesn’t overheat or run cool.

blockage. Check Coolant quality and

level.

Poor fuel economy

Monitor HEGO Sensor and Stepper

Engine Earth Straps and the HEGO

Motor position during idle, Acceleration,

Sensor are critical to efficient operation

Cruise and Deceleration. Ensure both are on LPG. Complete intake system

operating within normal ranges.

sealing and Air Filter Element condition

are also important for efficient operation

on LPG.

Poor starting

Check for deposits / contamination in the Refer above.

converter.
Verify Prime Valve operation on

Note that the Prime Valve operates

Cranking.

between 300-700 ms on Cranking but

there are certain situations where there

will be no prime operation.

All

Check sensitive diaphragm (under front)

The diaphragm must be free to move

cover for sludge or deposits

without sticking to the converter or being

weighed down.

NOTE: Leak test the LPG system after any

maintenance on LPG high pressure areas. Reset

KAM after any maintenance of the LPG system.

Connector Circuit Reference

LPG Converter C-913

Pin Number(s)

Circuit Designation/Description

Normal Condition/Measurement

1

Circuit 16H / (R-G)

0 voltage when ignition OFF, Greater than 10

Primary Lockoff power circuit

volts when engine cranking and running. Greater

than 10,000 ohms between lockoff and ground.

2

Circuit 57Y / (B)

0 voltage, less than 5 Ohms to chassis ground.

Secondary Lockoff ground circuit

3

Circuit 16X / (R-G)

0 voltage when ignition OFF, Greater than 10

Secondary Lockoff power circuit

volts when engine cranking and running. Greater

than 10,000 ohms between lockoff and ground.

4

Circuit 1500 / (B)

0 voltage, less than 5 ohms between solenoid

Primary Solenoid ground circuit

and EEC-C Pin C21 PRIM.

5

Circuit 57X / (B)

0 voltage, less than 5 Ohms to chassis ground

Primary Lockoff ground circuit

6

Circuit 592 / (W) S

12 volt square wave when measured across pin

tepper Motor Driver circuit

591 and 592. Greater than 10,000 ohms

between stepper motor and ground

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303-04c-27

Single Fuel LPG

303-04c-27

DIAGNOSIS AND TESTING (Continued)

Pin Number(s)

Circuit Designation/Description

Normal Condition/Measurement

7

Circuit 594 / (BR-B)

12 volt square wave when measured across pin

Stepper Motor driver circuit

593 and 594. Greater than 10,000 ohms

between stepper motor and ground

8

Circuit 361D / (R)

0 voltage when ignition OFF, Greater than 10

Primary Solenoid power circuit

volts when ignition ON and engine cranking and

running. Greater than 10,000 ohms between

solenoid and ground

9

Circuit 591 / (BR)

12 volt square wave when measured across pin

Stepper Motor driver circuit

591 and 592. Greater than 10,000 ohms

between stepper motor and ground

10

Circuit 593 / (BR-Y)

12 volt square wave when measured across pin

Stepper Motor driver circuit

593 and 594. Greater than 10,000 ohms

between stepper motor and ground

Stepper Motor C-910

Pin Number(s)

Circuit Designation/Description

Normal Condition/Measurement

1

Circuit 594 (BR-B)

12 volt square wave when measured across pin

593 and 594. Greater than 10,000 ohms

between stepper motor and ground.

2

Circuit 592 (W)

12 volt square wave when measured across pin

591 and 592. Greater than 10,000 ohms

between stepper motor and ground

3

Circuit 591 (BR)

12 volt square wave when measured across pin

591 and 592. Greater than 10,000 ohms

between stepper motor and ground

4

Circuit 593 (BR-Y)

12 volt square wave when measured across pin

593 and 594. Greater than 10,000 ohms

between stepper motor and ground

Primary Solenoid C-905

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