Ignition Coil(s) (1). Figure 1. Refer to
Spark Plug Wire Replacement.
5. Verify proper operation.

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Figure 3:
Driver side Ignition Coils #1, #3 and #7 (1).
NOTE: Ignition Coil #5 removed to show Valve Cover
Coil Mount Bosses (5) and Coil Mounting Bolt (4).

488LPI Propane Autogas Engine
Electrical and Sensors Manual

Page 23 of 31

Manifold Absolute Pressure (MAP) Sensor
Replacement
DESCRIPTION AND OPERATION
The Manifold Absolute Pressure (MAP) Sensor is a three (3) wire sensor that provides a signal to
the Engine Control Module (ECM) based on pressure changes in the Intake Manifold. Pressure
changes occur dependent on a combination of engine speeds, throttle openings, air temperature,
and barometric pressure. The ECM supplies five (5) volts to the MAP Sensor on the 5 V Reference
Circuit and Ground on the Low Reference Circuit.
The MAP Sensor provides a signal to the ECM on the Signal Circuit relative to intake pressure
changes. The MAP Sensor Signal is low during idle or deceleration. The MAP Sensor Signal is
high during Ignition ON, Engine OFF, or at Wide Open Throttle (WOT). The MAP Sensor also
measures barometric pressure (BARO). This occurs with Ignition ON, Engine OFF. The BARO
reading may also be updated whenever the Throttle Position Sensor (TPS) is at Wide Open
Throttle.
REMOVAL PROCEDURE
1. Secure vehicle.
2. Verify engine is off.
3. Disconnect Manifold Absolute Pressure
(MAP) Sensor (1) Electrical Connector (6)
from Engine Harness Connector (not
shown). Figures 1 & 2
4. Remove MAP Sensor Mounting Bolt (3).
Figure 1.
5. Remove MAP Sensor (1) from Upper
Intake Manifold (4). Figure 1
6. Inspect MAP Sensor O-Ring Seal (5) for
tears, dryness, or cracks. Figure 2
If O-ring is damaged, the MAP Sensor
must be replaced.

4
3
1

6

Figure 1:
Manifold Absolute Pressure (MAP) Sensor (1),
MAP Sensor Electrical Connector (6),
MAP Sensor Mounting Bolt (3),
Upper Intake Manifold (4)
1
6

5

Figure 2:
Manifold Absolute Pressure (MAP) Sensor (1),
MAP Sensor O-Ring Seal (5),
MAP Sensor Electrical Connector (6)

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Electrical and Sensors Manual

Page 24 of 31

INSTALLATION PROCEDURE
1. Lightly coat MAP Sensor O-Ring Seal (5)
with clean engine oil before installing sensor.
Figure 2

2.
3.

4.
5.

Apply clean engine oil with a sponge or a
brush. To prevent sensor blockage, avoid
dipping MAP Sensor port directly into
liquid.
Install MAP Sensor (1) on Upper Intake
Manifold (4). Figure 1
Install MAP Sensor Mounting Bolt (3) and
tighten. Figure 1. Refer to Electrical
Component & Sensor Torque
Specifications.
Connect MAP Sensor Electrical Connector
(6) to Engine Harness Connector (2).
Figures 1 & 2
Verify proper operation.

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Electrical and Sensors Manual

Page 25 of 31

Mass Air Flow (MAF) Sensor Replacement
DESCRIPTION AND OPERATION
The Mass Air Flow (MAF) Sensor provides a variable signal to the Engine Control Module (ECM)
dependent on the amount of air that is moving through the sensor to the engine. Powered by
battery voltage and ground, the MAF Sensor also incorporates an Intake Air Temperature (IAT)
Sensor. The ECM supplies 5 V to the MAF Sensor on the Signal Circuit which the sensor uses to
produce a frequency signal for the ECM.
REMOVAL PROCEDURE
1. Secure vehicle.
2. Disconnect Mass Air Flow (MAF)
Sensor (1) from Engine Harness
Electrical Connector (2). Figure 1
3. Remove two (2) MAF Mounting Bolts
(3) and Washers (not shown). Figure 1
4. Remove Mass Air Flow Sensor (1)
from Air Intake Tube (4). Figure 1
Inspect MAF Sensor (1) O-ring (not
shown) for cracks, dryness or
tears; if damage is found, MAF
Sensor must be replaced.

1

4

2

3

Figure 1:
Mass Airflow (MAF) Sensor (1),
MAF Sensor Electrical Connector (2),
MAF Sensor Mounting Bolts (3),
Intake Air Tube (4)

INSTALLATION PROCEDURE
1. Apply a thin coat of clean engine oil to
MAF Sensor O-Ring (not shown).
2. Install MAF Sensor (1) on Air Intake
Tube (4). Figure 1
3. Verify MAF Sensor Flow Direction Arrow
(5) points at Throttle Body. Figure 2
4. Install two (2) MAF Mounting Bolts (3)
and Washers (not shown) and tighten.
Figure 1. Refer to Engine Electrical &
Sensor Torque Specifications.
5. Connect MAF (1) to Engine Harness
Electrical Connector (2) at MAF
Connector (6). Figures 1 & 2
6. Verify proper operation.

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Electrical and Sensors Manual

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5

6

Figure 2:
Mass Airflow (MAF) Sensor (1),
Air Flow Direction Arrow (5),
Electrical Connector (6)

Page 26 of 31

Spark Plug Inspection
INSPECTION PROCEDURE
1. Verify vehicle has correct spark plugs installed.
Incorrect spark plugs can cause drivability
issues. Refer to Ignition System Specifications
for correct spark plug heat range.
Incorrect heat range spark plugs can cause the
following conditions:
a) Spark plug fouling; replace with hotter plug
b) Pre-ignition causing spark plug and/or
engine damage; replace with colder plug

1

2

2. Inspect Terminal Post (1) for damage:
a) Bent or broken terminal post
b) Loose terminal; test post by twisting and
pulling the post, terminal should not move.

3

4

3. Inspect Insulator (2) for the following conditions:
a) Carbon tracking or soot. This can cause
the electrical charge traveling across the
insulator to detonate air/fuel mixture
prematurely. Figure 2
b) Cracks. Inspect porcelain at electrode for
cracks. Figure 3

Figure 1:
Spark Plug components:
Terminal Post (1), Insulator (2),
Center Electrode (3), Side Electrode (4)
5

4. Inspect Spark Plug Recess in Cylinder Head for
the following conditions:
a) Moisture such as coolant or engine oil
b) Debris, dirty or damaged threads which
can cause spark plug not to seat correctly

Figure 2:
Spark Plug exhibiting carbon tracking (5)

5. Measure Spark Plug Gap between Center
Electrode (3) tip and Side Electrode (4) for
correct gap. Refer to Ignition System
Specifications for gap.
An excessively wide gap can cause engine
misfires and poor vehicle operation.

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Figure 3:
Spark Plug with crack (6) in porcelain Insulator

488LPI Propane Autogas Engine
Electrical and Sensors Manual

Page 27 of 31

Spark Plug Wire Inspection
Spark Plug Wires carry high voltage from the Ignition Coils to the Spark Plugs.
To maintain peak engine performance, Spark Plug Wires should be inspected periodically
to identify conditions that may affect engine operation.
INSPECTION PROCEDURE
1. Inspect Spark Plug Wires for the following conditions:

3

a) Cuts or tears in outer Wire (1) insulation or Boots
(2) and (3)
b) Oil contamination of Wire (1) or Spark Plug Boot
(2)

1

c) Signs of electrical arcing
d) Signs of heat penetration (scorch marks or burns)
e) Loose terminals/connectors at Spark Plug Boot
(2) or Ignition Coil Boot (3)
f) Corrosion on terminals at Spark Plug Boot (2) or
Ignition Coil Boot (3)
g) Carbon Tracking on terminals at Spark Plug Boot
(2) or Ignition Coil Boot (3)

2
Figure 1:
Spark Plug Wire components:
Insulated Wire (1), Spark Plug Boot (2),
Ignition Coil Boot (3)

Never pull on Spark Plug Wires to remove wire from
Spark Plugs or Coils; always grasp the Spark Plug
Boot or Coil Boot to remove.
Use a Spark Plug Wire Boot Removal Tool to
remove Boots from Terminal Connectors.
2. If any of the above conditions are found, replace
damaged Spark Plug Wire and any component
connected to it.

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Electrical and Sensors Manual

Page 28 of 31

Torque Security Module (TSM) Replacement
DESCRIPTION AND OPERATION
The Torque Security Module (TSM) works with the Engine Control Module (ECM) to monitor and
direct engine and accessory operation. The TSM connects to the Engine Harness using a single
large electrical connector and attaches to the Upper Intake Manifold via a bracket.
REMOVAL PROCEDURE
1. Secure vehicle.
2. Ignition OFF.
3. Disconnect Torque Security Module
(TSM) Engine Harness Electrical
Connector (2) from TSM (1). Figure 1
4. Remove three (3) TSM Mounting Bolts
(4). Figure 1
5. Remove TSM (1) and TSM Mounting
Bracket (6) from Upper Intake Manifold
(7). Figure 2
6. Remove TSM (1) from Mounting
Bracket (6). Figure 2

3

7

4

2

1

Figure 1:
TSM (1), Engine Harness TSM Electrical Connector
(2), Engine Harness (3), TSM Mounting Bolts (4),
Upper Intake Manifold (7)

INSTALLATION PROCEDURE
1. Install TSM (1) on Mounting Bracket
(6). Figure 2
2. Install TSM to Upper Intake Manifold
(7) using three (3) TSM Mounting Bolts
(4) and tighten. Figures 1 & 2. Refer to
Electrical Component & Sensor Torque
Specifications.
Apply dielectric grease to connector.
3. Connect Engine Harness Electrical
Connector (2) to TSM Electrical
Connector location (5). Figure 2
Verify connector security locks are
firmly in place.
4. Verify proper operation.

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4

5

Figure 2:
TSM (1), TSM Electrical Connector location (5),
TSM Mounting Bolt (4), TSM Mounting Bracket (6),
Upper Intake Manifold (7)

488LPI Propane Autogas Engine
Electrical and Sensors Manual

Page 29 of 31

Electrical Components and Sensors
Torque Specifications
APPLICATION

SPECIFICATION
Metric
Standard

Camshaft Position (CMP) Sensor Bolt

12 Nm

9 ft-lbs

Crankshaft Position (CKP) Sensor Bolt

12 Nm

9 ft-lbs

Engine Coolant Temperature (ECT) Sensor

50 Nm

37 ft-lbs

Engine Control Module (ECM) Bolts

15 Nm

11 ft-lbs

Engine Harness Bracket Bolt

25 Nm

18 ft-lbs

Engine Harness Clip Bolt

12 Nm

9 ft-lbs

Engine Harness Ground Rings

F.S.N.S.*

Fuel Pressure/Temperature (FPT) Sensor

9 Nm

6.5 ft-lbs

Fuel By-pass Solenoid Nut

12 Nm

9 ft-lbs

Ground Strap Bolt

50 Nm

37 ft-lbs

Ignition Coil Bolts

12 Nm

9 ft-lbs

Ignition Coil Wiring Harness Bolt

12 Nm

9 ft-lbs

Manifold Absolute Pressure (MAP) Sensor Bolt

15 Nm

11 ft-lbs

Mass Air Flow (MAF) Sensor Bolts

4 Nm

3 ft-lbs

Oil Level Sensor

20 Nm

15 ft-lbs

Oil Pressure Sensor

30 Nm

23 ft-lbs

Spark Plug

30 Nm

23 ft-lbs

Throttle Body Bolt

15 Nm

11 ft-lbs

Torque Security Module Bracket Bolts

15 Nm

11 ft-lbs

*F.S.N.S. = Fully Seated, Not Stripped

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Electrical and Sensors Manual

Page 30 of 31

Ignition System Specifications
APPLICATION

SPECIFICATIONS

Ignition Type

Individual Ignition Coil

Firing Order

1–8–7–2–6–5–4-3

Spark Plug Wire Resistance

170-220 Ω per 25.4 mm (1.0-in)

Spark Plug Torque*

30 Nm (22 ft-Ibs)

Spark Plug Gap

1.14 mm (0.045-in)

Spark Plug Type

Hexagon Agility® p/n 69000567

*Hexagon Agility® does not recommend or promote the use any type of anti-seize
lubricant on spark plug threads. Plugs should be installed as boxed (dry).

Do not mix different types of spark plugs.

FRONT

Passenger
side

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5

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Driver
side

488LPI Propane Autogas Engine
Electrical and Sensors Manual

Firing order

1–8–7–2–6–5–4–3

Page 31 of 31