4
5
Figure 4:
Install removal tool (4) on
Harmonic Damper (2)

2

6

Figure 5:
Harmonic Damper (2) and
Crankshaft snout (6)

2

7
Figure 6:
Tighten nut on special tool (7) to seat
Harmonic Damper (2) on Crankshaft
snout (6)

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and Fuel Components Service Manual

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INSTALLATION PROCEDURE
RECOMMENDED: Replace Front
Crankshaft Seal prior to reassembly. Refer
to Front Crankshaft Seal Replacement.
1. Install Alignment Key (not shown) and
Harmonic Damper (5) on Crankshaft
snout (6). Figure 5
Position Harmonic Damper as straight
as possible on Crankshaft. Apply a
coat of clean engine oil to Crankshaft
snout and inside Harmonic Damper to
prevent galling during assembly.
2. Install special tool (7) on Harmonic
Damper (5). Figure 6
Lubricate tool threads with antiseize grease before each use.
3. Using special tool (7), press Harmonic
Damper on Crankshaft nose.
4. Tighten special tool nut until Harmonic
Damper is completely seated against
Crankshaft Timing Sprocket and remove.
5. Install new Harmonic Damper Flanged
Bolt (1). Figure 2. Refer to Engine
Mechanical Torque and Clearance
specifications.
6. If equipped: Install Dual A/C Drive
Pulley. Refer to Front End Accessory
Drive Components Replacement.
7. If equipped: Install Air Compressor Belt.
Refer to Air Compressor Belt
Replacement.
8. Install Main Accessory Belt. Follow OEM
procedure.
9. Install Cooling Pack. Follow OEM
procedure.
10. Raise vehicle.
11. Remove Flywheel Holding Tool. Figure 1
12. Install Transmission Adapter. Refer to
Flexplate & Transmission Adapter
Replacement.
13. Fill engine fluids. Follow OEM
specifications.
14. Verify proper operation.

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and Fuel Components Service Manual

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Lower Intake Manifold Replacement
REMOVAL PROCEDURE

Drain fuel lines prior to towing or pushing
vehicle into shop. Refer to NPFA 58 Fuel Line
Bleed Procedure.

10
1

11

Remove air filter housing bracket (along with
filter housing and hose) from the firewall by
removing the four T40 Torx bolts.

If the vehicle is equipped with single or
dual A/C compressors Refer to A/C
Compressor Removal Procedure.
1. Loosen Air Intake Tube hose clamps,
remove the air filter housing bracket (along
with the filter housing and hose) by
removing four T40 Torx bolts.
2. Drain engine coolant. Follow OEM
procedure.
3. If equipped with Air Conditioning:
a. Remove upper Dual A/C Compressor
(not shown), OR
b. Remove Single A/C Compressor (not
shown). Follow OEM procedure.
4. Remove Upper Intake Manifold and Air
Intake Tube (both not shown) as an
assembly. Refer to Upper Intake Manifold
Replacement.
5. Disconnect Fuel Supply and Fuel Return
Hoses (not shown) at respective Fuel
Distribution Blocks (16) and (17). Figure 4.
Refer to Fuel Supply and Return Line
Replacement.
6. If equipped: Remove Air Compressor
Coolant Feed Line Flare Nut (8) from rear of
Lower Intake Manifold (1). Figure 1. Refer
to Air Compressor Replacement.

8
Figure 1:
Air Compressor Coolant Feed Line Flare Nut (8) at
Lower Intake Manifold (1) rear; Electrical Bulkhead
Connector Bracket (10), Retaining Bolts (11)
21

7
19
1
3

20

Figure 2:
Lower Intake Manifold (1), Coolant By-Pass Adapter (20),
Heater Coolant Feed Line Flare Nut (3),
Upper Radiator Hose location (7),
Thermostat Housing (19),
Upper Intake Manifold Mounting Studs (21)

Collect coolant for reuse or proper
disposal.

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and Fuel Components Service Manual

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7. Disconnect Upper Radiator Hose (not shown)
from Thermostat Housing (7). Figure 2. Refer to
Thermostat Replacement.
8. Disconnect Coolant By-pass Hose (not shown)
at Lower Intake Tube Adapter (20). Figures 2 &
3
9. Disconnect Heater Coolant Feed Line Flare Nut
(3) at Lower Intake Manifold 90° Nipple Adapter
(not shown). Figure 2
10. Remove twelve (12) Lower Intake Manifold
Retaining Bolts (12) and Washers (13). Figure
3
11. Remove Lower Intake Manifold Assembly (1)
from Engine. Figure 2
12. Remove Lower Intake Manifold Gaskets (4) and
discard. Figure 3

12
1

13

19
25

4

20

15

16

14

18

1

FRONT

Figure 3:
Lower Intake Manifold (1), Lower Intake Gaskets (4),
Bolts (5), Washers (6); Coolant By-pass Hose
Adapter (20), Thermostat Housing (19),
Valley Pan (25)

17

Figure 4:
Lower Intake Manifold (1), Fuel Rails (18),
Fuel Distribution Block Bracket (14), Bolts (15),
Fuel Supply Distribution Block (16),
Fuel Return Distribution Block (17).
NOTE: Fuel Supply and Return Lines not shown.

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and Fuel Components Service Manual

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INSTALLATION PROCEDURE

23

4

1. Remove any RTV Silicone residue from
Lower Intake Manifold, Cylinder Head and
Engine China Wall sealing surfaces.
Figure 5
6

Use care around ports to avoid
contamination.

2.
3.
4.
5.

Lower Intake Manifold is aluminum;
use care in removing gasket/RTV
material.
Clean all Lower Intake Manifold mating
surfaces with isopropyl alcohol. Figure 5
Verify Valley Pan (25) is in place. Figure 3
Apply a 0.25-in (6mm) to 0.50-in (12.5mm)
bead of engine RTV Silicone around Lower
Cylinder Head Coolant Ports (22). Figure 5
Install new Lower Intake Manifold Gaskets
(4) on Cylinder Heads (24).

24

22

5

FRONT

Figure 5:
Lower Intake Manifold Gasket (4), Gasket Alignment
Tabs (6), Gasket Coolant Ports (23)
Cylinder Head Coolant Ports (22); China Walls (5)

Verify Gasket Alignment Tabs (6)
are fully seated. Figure 5
6. Apply 3 beads 0.25-in (6mm) to 0.50-in
(12.5mm) of High Temp RTV Silicone to
the Engine China Walls, 2 beads along the
China wall and the 3rd bead on top of the 2
beads on the China Walls (5). Figure 5
7. Apply a 0.25-in (6mm) to 0.50-in (12.5mm)
bead of High Temp RTV Silicone to Lower
Intake Manifold Gaskets (4) around Gasket
Coolant Ports (23). Figure 5
8.

It is recommended that two people
carefully center Lower Intake Manifold
(1) when placing on engine; this will
prevent High Temp RTV from being
dislocated from China Wall and allow
for a proper seal. Figure 2

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and Fuel Components Service Manual

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If not pre-applied: Apply Loctite® 565
PST Pipe Sealant to Lower Intake
Manifold Bolts (12). Figure 3
10. Install Lower Intake Manifold Bolts (12)
and Washers (13). Figure 3

5

Start all bolts by hand and run
down until hand tight.
Tighten Intake Bolts (12) following
torque sequence in Figure 6. Refer to
Engine Mechanical Torque and Clearance
Specifications.
12. Connect Upper Radiator Hose to
Thermostat Housing (19) at location (7).
Figure 2. Refer to Thermostat
Replacement.
13. Connect Heater Core Coolant Feed Line
Flare Nut (3) at Lower Intake 90° Nipple
Adapter (not shown). Figure 2
14. Connect By-pass Hose (not shown) at
Lower Intake Manifold Tube Adapter (9).
Figure 2
15. If equipped: Install Air Compressor Coolant
Feed Line (8) to Lower Intake Manifold (1)
rear. Figure 1
16. Connect Fuel Supply and Fuel Return
Hoses at respective Distribution Blocks
(16) and (17). Figure 4. Refer to Fuel
Supply and Return Line Replacement.
17. Pressurize fuel system to prepare for leak
check as follows:
a. Open Fuel Tank Supply and Return
Valves. Refer to OEM procedure.
b. Use a Power Probe or similar tool to
apply power to two wires of the Fuel ByPass Solenoid (11) Electrical Connector
(12) to pressurize fuel system. Figure 7
17. Perform leak check. Refer to Fuel System
Leak Check Procedure.
18. Install Upper Intake Manifold (not shown).
Refer to Upper Intake Manifold
Replacement.

12

10

®

7

FRONT

9.

3
1

11.

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4

6
8

9

11

Figure 6:
Lower Intake Manifold Retaining
Bolt Torque Sequence
(numbered locations)

18

27

26

Figure 7:
Fuel By-Pass Solenoid (26), Electrical Connector (27),
Fuel Return Distribution Block (18)

488LPI Propane Autogas Engine Mechanical
and Fuel Components Service Manual

Page 79 of 117

19. If equipped:
a. Install Single A/C Compressor, OR
b. Install Dual A/C Compressor.
Follow OEM procedure.
20. Fill cooling system. Follow OEM
procedure; refer to 488LPI™ Owners
Manual for coolant specifications.
21. Clean any spilled fluids from engine.
22. Bring engine up to operating temperature
and verify proper operation.

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and Fuel Components Service Manual

Page 80 of 117

Main Front End Accessory Drive (FEAD)
Bracket Replacement
REMOVAL PROCEDURE
1. Secure vehicle.
2. Ensure engine is off and cool.
NOTE: For Steps 4 & 5, refer to OEM
Main Accessory Drive Belt Replacement
to remove tension on respective belts.
3. If equipped: Remove A/C Drive Belt.
4. Remove Main Accessory Drive Belt.
5. Remove Air Compressor. (not shown)
Refer to Air Compressor Replacement.
6. If equipped: Remove Air Compressor
Bracket (3). Figure 1. Refer to Air
Compressor Bracket Replacement.
7. Remove Power Steering Pump (not
shown) from Main Front Engine
Accessory Drive (FEAD) Bracket position
(5). Figure 1. Follow OEM procedure.
8. Remove Alternator (not shown) from Main
FEAD Bracket position (4). Figure 1.
Refer to Alternator Removal.
9. Remove three (3) Upper Bolts (2) and
Washers (6) and Lower Bolt (7) and
Washer (8). Figure 1.

4

2
3
1

6

7

8

5

Figure 1:
Main Front End Accessory Drive (FEAD) Bracket (1),
Air Compressor Bracket (3); Upper Bolts (2) and
Washers (6), Lower Bolt (7) and Washer (8),
Power Steering Pump location (5),
Alternator location (4),

Bolt (7) and Washer (8) are different
from (2) and (6).
10. Remove Main FEAD Bracket (1) from
engine. Figure 1
Bracket is heavy, and accessory drive
pulleys will remain attached. Please
take necessary precautions when
handling to prevent personal injury or
component damage.

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and Fuel Components Service Manual

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INSTALLATION PROCEDURE

Bracket is heavy, and accessory drive
pulleys will remain attached. Please
take necessary precautions when
handling to prevent personal injury or
component damage.
1. Thread one (1) Upper Bolt (2) and
Washer (6) through Main FEAD Bracket
(1) and into engine block. Figure 2.
2

Bolt holds Bracket temporarily and
eases alignment.
2. Align Main FEAD Bracket (1) to engine
(not shown). Figure 1
3. Install remaining two (2) Upper Bolts (2)
and Washers (6) and Lower Bolt (7) and
Washer (8) (not shown). Figure 1.
4. Torque all four (4) Main Accessory Drive
Retaining Bolts (2 & 7). Figure 1. Refer
to Front End Accessory Drive Torque
Specifications.
5. Install Power Steering Pump. Follow
OEM procedure.
6. Install Alternator. Refer to Alternator
Removal Procedure.
7. If equipped: Install Air Compressor
Bracket. Refer to Air Compressor
Bracket Replacement.
8. If equipped: Install Air Compressor.
Refer to Air Compressor Replacement.
9. Install Main Accessory Drive Belt. Follow
OEM procedure and route belt according
to OEM diagram.
10. If equipped: Install A/C Drive Belt. Follow
OEM procedure and route belt according
to OEM diagram.
11. Verify proper operation.

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1

Figure 2:
Thread one (1) Upper Bolt (2) and Washer (6) to
locate Main Accessory Drive (1) on engine.
NOTE: Accessory Pulleys and optional Air
Compressor Bracket not shown.

488LPI Propane Autogas Engine Mechanical
and Fuel Components Service Manual

Page 82 of 117

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