Engine Controls - Remove/install/overhaul - 5.2l Cng Dodge Ram Wagon B3500

INTRODUCTION

Note. For component location, see THEORY/OPERATION - 5.2L CNG article in the ENGINE PERFORMANCE section.

Removal, overhaul and installation procedures (when given by manufacturer) are covered in this article. If component removal and installation is primarily an unbolt and bolt-on procedure, only a torque specification may be provided. The following components are similar or identical to gasoline-powered version. See the REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE article in the ENGINE PERFORMANCE section.

1. Throttle Body
2. MAP Sensor
3. Engine Coolant Temperature Sensor
4. Intake Manifold
5. Throttle Position Sensor
6. Idle Air Control Motor
7. Crankshaft Position Sensor
8. ASD Relay (Different Function)
9. Heated Oxygen Sensor
10. Vehicle Speed Sensor
11. All Ignition Components (Except PCM)

IGNITION SYSTEM

Note. For servicing information on this system, see REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE article in the ENGINE PERFORMANCE section.

SAFETY PRECAUTIONS

FUEL SYSTEM PURGING

Fuel system must first be purged of natural gas if any of following components are to be removed or repaired.

1. Fuel Tube Or Fuel Tube Fitting
2. Fuel Injector Rail Assembly
3. Fuel Temperature Sensor
4. Fuel Low-Pressure Sensor
5. Fuel Gauge Pressure Sensor
6. Fuel Fill Receptacle
7. Fuel Cylinder
8. Manual Shutoff Valve
9. Fuel Filter
10. Fuel Injectors
11. Low-Pressure Fuel Shutoff Solenoid
12. Fuel Pressure Regulator
13. Fuel Fill Check Valves
14. High-Pressure Fuel Shutoff Solenoid

Fuel Tubes Purging

Use this procedure if servicing fuel system components OTHER THAN fuel cylinders. Close control valve (clockwise) on all fuel cylinders. Open manual shutoff valve. (Scheme 4) Start engine and operate until engine runs out of fuel. Attempt 3 more engine starts. Very slowly loosen both inlet and outlet fuel tube fittings on the pressure regulator until all pressure is relieved.

If servicing check valve or fuel fill receptacle, slowly loosen inlet side of fuel fill tube fitting at check valve. (Scheme 11) Pressurized natural gas may flow from loosened fitting. All fuel tubes are now purged of natural gas between fuel cylinders and engine; fuel system may be opened for repair.

Scheme 4

Fuel Cylinder Purging

1. Open manual shutoff valve. (Scheme 4) Open fuel control valves (counterclockwise) only on fuel cylinders to be serviced. Close all control valves (clockwise) on fuel cylinders not being serviced.
2. Start engine and operate until it runs out of fuel. Attempt 3 more engine starts. All fuel tubes and opened cylinders are now purged of natural gas between fuel cylinders and engine; fuel system may be opened for repair.
3. If engine will not start, move vehicle outdoors. Loosen fuel tube at cylinder to be serviced. Wait until all pressure has been released. Fuel cylinder may now be removed.

Service Precautions

Due to high-pressure requirements of CNG system, stainless steel, double-ferrule, compression-type fuel tube fittings are used. Following precautions should be observed when servicing these fuel tubes

1. Use only OE standard replacement parts.
2. DO NOT allow fuel tube ends to become scratched. Leaks will occur.
3. Check and remove burrs from end of fuel tubes.
4. DO NOT attempt to loosen or tighten fitting with fuel system under pressure.
5. NEVER attempt to force fuel tube into fitting or ferrule. Tubes should fit easily.
6. Fuel tubes are under EXTREME high pressure. DO NOT substitute tubes made of any other material other than OE equipment.
7. ALWAYS use a back-up wrench when loosening or tightening fuel fittings to prevent fuel tube from twisting.
8. Two sizes of fuel tubes are used, 1/4" and 3/8". ALWAYS use proper size.

Removal (Double-Ferrule Type Fittings)

See SAFETY PRECAUTIONS . Use a back-up wrench to loosen fittings to prevent fuel tube from twisting.

Installation (New Fittings)

1. See «SAFETY PRECAUTIONS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__safety-precautions). Install tube into fitting assembly. (Scheme 5) Tighten fitting finger tight. Scribe a mark at 6 o'clock position on fitting. (Scheme 6)
2. Using a wrench and a back-up wrench, tighten fitting 1 1/4 turns. Scribe mark should be at 9 o'clock position. (Scheme 6) Check fitting using go/no-go gauge. (Scheme 7) Fitting is properly tightened if go/no-go gauge does not fit between fitting and fitting body. CAUTION: DO NOT install go/no-go gauge to fitting while tightening; use gauge only for fitting check.
3. If go/no-go gauge fits between fitting and fitting body after tightening fitting 1 1/4 turns, slowly continue to tighten fitting in small increments until gauge no longer fits. DO NOT overtighten fitting. Leak test fitting.

Scheme 5

Scheme 6

Scheme 7

Installation (Used Fittings)

1. Install tube with pre-swaged, collapsed ferrule into fitting body until ferrule is seated. Tighten fitting by hand. Using a wrench and a back-up wrench, tighten fitting until increase in resistance is felt.
2. Slowly tighten fitting an additional 1/12 turn. DO NOT overtighten fitting. Check fitting using go/no-go gauge. If go/no-go gauge still fits between fitting and fitting body, replace fitting. When complete, leak test.

Removal (High-Pressure "O" Ring Type Fittings)

Certain fuel fittings use "O" rings. (Scheme 8) When removing 90-degree type fittings, loosen lock nut first to prevent "O" ring damage. (Scheme 9)

Installation

Apply Parker O-Lube(R) to NEW "O" rings. On 90-degree fittings, back off lock nut as far as possible. Thread fitting into port until back-up washer contacts port face. (Scheme 9) Rotate fitting to desired position. DO NOT unscrew fitting more than one full turn. Hold fitting in position, and tighten lock nut.

Scheme 8

Scheme 9

FUEL INJECTOR & RAILS

Note. Fuel rail sections are connected with a non-serviceable flexible connecting hose. DO NOT attempt to separate rail halves from connecting hose.

Removal & Installation

1. Remove engine cover. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging) . Disconnect fuel injector harness connector at each injector. CAUTION: Fuel injector harness connectors are numbered and MUST be reinstalled on correct injector.
2. Remove throttle body. Refer to «REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-gasoline) article in the ENGINE PERFORMANCE section. Remove intake manifold-to-fuel rail retaining bolts. Remove A/C compressor support bracket.
3. Disconnect harness connectors from fuel low-pressure sensor, fuel temperature sensor and low-pressure fuel shutoff solenoid. Disconnect fuel tube from low-pressure fuel shutoff solenoid. Fuel line to solenoid utilizes a copper washer.
4. Remove low-pressure fuel shutoff solenoid support bracket. Remove fuel tube from rail. Remove fuel rail retaining bolts, and lift rail straight up and out of manifold using a rocking motion. To remove injector, remove clip retaining injector to fuel rail. CAUTION: To prevent fuel rail misalignment, install fuel tube before installing intake manifold-to-fuel rail retaining bolts.
5. To install, reverse removal procedure. Clean all components thoroughly. Install NEW "O" rings (CNG type), and apply Parker O-Lube(R) to "O" rings as components are assembled.

Release fuel system pressure. See FUEL SYSTEM PURGING . Disconnect harness connector at sensor. Remove sensor from fuel rail. To install, reverse removal procedure.

Release fuel system pressure. See FUEL SYSTEM PURGING . Disconnect harness connector at sensor. Remove sensor from fuel rail. To install, reverse removal procedure.

1. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging). Raise and support vehicle. Clean area around fuel tubes and fittings at fuel pressure regulator and manual shutoff valve.
2. Disconnect fuel tube at fuel pressure regulator and manual shutoff valve. Remove fuel tube fitting from fuel pressure regulator. Remove filter retention spring, filter and "O" ring. (Scheme 10) NOTE: DO NOT let foreign material enter fuel pressure regulator.
3. To install, reverse removal procedure. Apply anaerobic sealant containing Teflon(R) to threads on fitting. DO NOT get sealant in fuel system. Check fuel tube for proper tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng).

Scheme 10

1. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging) . Drain a small amount of coolant from radiator. Raise and support vehicle.
2. Place a drain pan under fuel pressure regulator, and disconnect coolant hoses. Disconnect regulator harness connector. Clean area around fuel tubes and fittings. Disconnect fuel tubes. Remove 4 regulator-to-frame rail mounting bolts, and remove regulator.
3. To install, reverse removal procedure. Tighten fuel pressure regulator-to-frame rail mounting bolts to specification. See «TORQUE SPECIFICATIONS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__torque-specifications) . Connect fuel tubes, and check for tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng) .

LOW-PRESSURE FUEL SHUTOFF SOLENOID

1. Low-pressure fuel shutoff solenoid is located on fuel injector rail. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging) . Remove engine cover. Remove air filter assembly. Remove TP sensor harness connector and power brake booster vacuum hose at intake manifold.
2. Disconnect solenoid harness connector. Remove fuel tube from low-pressure fuel shutoff solenoid. Note direction of copper washer when removing fuel line. Remove solenoid from fuel injector rail. To install, reverse removal procedure. Apply thread sealer to solenoid pipe threads.

HIGH-PRESSURE FUEL SHUTOFF SOLENOID

High-pressure fuel shutoff solenoid is integral to fuel pressure regulator. If solenoid is defective, fuel pressure regulator must be replaced. See FUEL PRESSURE REGULATOR .

1. Valve is located inboard of frame rail, near right rear wheel housing. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging) . Raise and support vehicle. Remove rubber or steel (as equipped) shield around valve.
2. Clean area around fuel tube fittings, and disconnect fuel tubes. Remove manual shutoff valve handle. Remove valve mounting bracket retaining bolts, and remove valve assembly. Remove valve from mounting bracket.
3. Install valve mounting bracket and valve assembly to frame rail. Tighten manual shutoff valve mounting bracket retaining bolts to specification. See «TORQUE SPECIFICATIONS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__torque-specifications) . Apply thread locking compound to valve mounting nut and tighten. Check fuel tubes for proper tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng) .
4. Install valve handle, and tighten set screw. Check tubes and fittings for leaks. To complete installation, reverse removal procedure.

FUEL FILL CHECK VALVES

Note. CNG vehicles use 2 fuel fill check valves. One check valve is located on frame rail near top of left rear shock absorber. Other check valve is integral to fuel fill receptacle. If this check valve is defective, fuel fill receptacle MUST be replaced. See FUEL FILL RECEPTACLE .

Removal & Installation (Frame-Mounted Check Valve)

1. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging). Raise and support vehicle.
2. Disconnect fuel tube fittings from either end of check valve. (Scheme 11) Note direction of valve mounting, and remove check valve. To install, reverse removal procedure. Check fuel tube fittings for proper tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng).

Scheme 11

1. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging) . Remove shield(s) as needed. Disconnect fuel tube from fuel fill receptacle. Remove receptacle mounting nut. Remove receptacle.
2. Install receptacle in mounting bracket. Apply thread locking compound to receptacle threads, and install mounting nut. Connect fuel tube. Check fuel tube for proper tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng) .

FUEL CYLINDER CONTROL VALVE

Note. Fuel cylinders need to be removed or lowered to gain access for control valve removal. See FUEL CYLINDER CONTROL VALVE ACCESS table. For fuel cylinder lowering or removal procedures, see FUEL CYLINDERS .

FUEL CYLINDER CONTROL VALVE ACCESS

Removal

Release fuel system pressure. See FUEL SYSTEM PURGING . Ensure cylinder is empty. Clean area around fuel tube fitting, and disconnect fuel tube. Disconnect fuel gauge pressure sensor harness connector (if applicable). Remove fuel cylinder control valve (counterclockwise).

1. Apply Parker O-Lube(R) to NEW "O" ring, and install "O" ring on fuel cylinder control valve. Install control valve. Loosen cylinder strap, and rotate cylinder until control valve is in horizontal position. Tighten cylinder strap bolts.
2. Apply Parker O-Lube(R) to NEW "O" ring, and install "O" ring on fuel gauge pressure sensor. Install pressure sensor and sensor harness connector. Connect fuel tube, and check for proper tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng) . Install cylinder guard, and tighten bolts.

FUEL CYLINDERS

Note. U.S. Department Of Transportation (DOT) requires fuel cylinders be retested every 3 years from date of manufacture. Fuel cylinders expire and must be removed from service 15 years from date of manufacture. A label affixed to fuel filler door states first cylinder retest date and cylinder expiration date.

Note. For model specific removal and installation procedures, see appropriate SPECIFIC REMOVAL & INSTALLATION PROCEDURES under FUEL CYLINDERS .

General Removal & Installation Procedures

1. Release fuel system pressure. See «FUEL SYSTEM PURGING»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__fuel-system-purging) . Raise and support vehicle. Remove all applicable heat shields, rock guards and cylinder guards. Clean area around all fuel tube connections. Disconnect applicable fuel tubes.
2. Disconnect fuel gauge pressure sensor harness connector. Support fuel cylinder or cylinder carrier assembly using appropriate jack. Ensure cylinder(s) are balanced and secure on jack lifting surface. Remove cylinder carrier or strap mounting bolts.
3. Lower cylinder or cylinder assembly from vehicle. If cylinder carrier assembly is being held in place by adhesive, gently pry assembly loose using a wide-blade screwdriver. Mark cylinder-to-cylinder carrier position for reassembly reference. Remover carrier strap nuts, and remove cylinder from carrier (if applicable). If cylinder is being replaced, remove fuel cylinder control valve. Ensure cylinder is empty before removing control valve.
4. To install cylinder(s), position cylinder in carrier (as applicable). Raise cylinders in position, and install cylinder carrier straps in parallel position. Secure cylinder assembly as needed in reverse order of disassembly. Tighten cylinder carrier strap nuts to specification. See «TORQUE SPECIFICATIONS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__torque-specifications) .
5. If fuel cylinder control valve was removed, install valve using NEW "O" rings. Apply Parker O-Lube(R) to NEW "O" rings. Tighten fuel cylinder control valve to specification. Proceed to «TORQUE SPECIFICATIONS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng__torque-specifications) . Connect fuel tube and check for proper tightness using go/no-go gauge. See «FUEL TUBES & FITTINGS»(/dodge/ram-wagon-b3500/1991-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul-52l-cng) . Connect fuel gauge pressure sensor harness connector. Apply thread locking compound to fuel control valve guard mounting bolts. Install guard, and tighten bolts. Install heat shield.

Specific Removal & Installation Procedures

1. 2 rear cylinders are removed as an assembly by removing carrier assembly bolts located under carpeting (if equipped). Rear seat and spare tire may also need removal. Support cylinders with appropriate jack before bolts are removed.
2. Left side cylinder is removed as an assembly with carrier bracket assembly. Two carrier bracket bolts are located inside vehicle, behind driver's seat, and 2 bolts are on frame rail. Ensure reference marks are used to return cylinder and control valve to original position. The right cylinder is removed as an assembly from frame rail. Securing bolts are threaded into weld nut plates in interior of frame rail. To access weld nut plates, remove access plugs in floor of vehicle near step well.

HEATED OXYGEN SENSOR (HO2S)

See REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE article in the ENGINE PERFORMANCE section.

THROTTLE BODY

See REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE article in the ENGINE PERFORMANCE section.

THROTTLE POSITION SENSOR

See REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE article in the ENGINE PERFORMANCE section.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• COMPUTER RELEARN PROCEDURES
• THEORY/OPERATION - 5.2L CNG
• REMOVE/INSTALL/OVERHAUL - 5.2L GASOLINE
• COMPRESSED NATURAL GAS SAFETY PRECAUTIONS
• FUEL TUBES & FITTINGS
• SAFETY PRECAUTIONS
• FUEL SYSTEM PURGING
• TORQUE SPECIFICATIONS
• FUEL CYLINDERS