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Engine Controls - Remove/install/overhaul: Other GMC Vandura P3500

Removal & Installation 1 illustration ~432 words

CONTROL UNIT

CAUTIONWhen certain materials rub together, a transfer of electrons from one material to another may occur under special conditions. This causes electrostatic charge (static electricity) build up in one of the materials. When any conducting material comes in contact with the charged material, electrostatic discharge occurs, transferring electrons to the third material. Electronic components used in control systems are designed to carry very low voltages; a 30-volt charge created by static electricity can cause a total or degrading failure in ECM or other electronic components containing integrated circuits. Before servicing ECM, ground yourself, and ground the work area to discharge stored electricity.
MovementRelative Humidity 10-20%Relative Humidity 65-90%
Walking Across Carpet35,0001500
Handling Clear Plastic Bag20,0001200
Sliding Across Velour Seat15,000400
Walking Across Tile/Vinyl12,00050
Handling Vinyl Envelope7000600

STATIC CHARGE (VOLTS)

CAUTIONStatic electricity can destroy integrated circuits within ECM. Before servicing ECM, ground yourself and the work area to discharge stored electricity.
CAUTIONDO NOT remove ECM from packaging until ready to install. Ground static-proof package BEFORE opening. DO NOT touch electrical terminals of components unless properly grounded. DO NOT lay electrical components on car seat, carpeting or dashboard. Use electrostatic protection mat and ground strap whenever possible. (Scheme 7)

Replacing ECM While Using 3M Anti-Static Mat. Scheme 7

Scheme 7: Replacing ECM While Using 3M Anti-Static Mat

Note. Before replacing ECM, carefully inspect all wiring and control components. Ignition switch must be in OFF position when connecting or disconnecting ECM connector.

ELECTRONIC SPARK CONTROL (ESC) MODULE

Note. The ESC is located on a bracket behind the distributor, mounted to firewall.

FUEL SYSTEM PRESSURE RELIEF

Fuel system is under pressure. Fuel pressure may be relieved by 2 different methods.

Method 1

Disconnect fuel pump electrical connector. Start engine and allow to run until it stops. Operate starter for 3 seconds to remove remaining fuel from fuel lines.

Method 2

Install Fuel Pressure Gauge (J-34730-1) on fuel pressure connection. Wrap shop towel around pressure connection when installing fuel pressure gauge to absorb fuel leakage. Place gauge bleed hose in container. Open bleed valve to bleed fuel pressure.

FUEL RAIL & INJECTORS

Note. Upper intake manifold must be removed in order to remove fuel rail and injectors.

TBI Unit Model 700

Place transmission gear selector in Park (Neutral on M/T). Set parking brake and block drive wheels. Loosen fuel filler cap to relieve tank pressure. Disconnect 3-terminal electrical connector at fuel tank. Start engine and allow to run until engine stalls. Crank engine for 3 seconds to relieve any residual pressure left in fuel lines. Fuel lines are now safe for servicing.

TBI Unit Model 220

Fuel pressure is relieved and drops to zero when ignitions is turned off.

WARNINGTo minimize risk of fire and personal injury, cover area to be disconnected with a shop rag.

Fuel Pump

  1. Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELIEF under FUEL SYSTEM (TBI). Disconnect negative battery terminal. Raise vehicle and remove fuel tank. Remove sender unit and pump by turning cam lock counterclockwise using Tool (J-36608 or J-24187).
  2. Remove fuel pump from sending unit by pulling pump up into attaching hose while pulling outward from the bottom support. DO NOT damage rubber insulator or strainer. To install, reverse removal procedure.

Note. When installing sending unit, DO NOT fold or twist strainer. This will restrict fuel flow.

OXYGEN (O2) SENSOR

CAUTIONO2 sensor is equipped with a permanent pigtail, which must be protected to prevent damage when removing sensor.

CHARGE AIR SYSTEM BLEEDING

  1. Open petcock on charge air cooler radiator. Fill charge air cooler radiator with a 56/44 mixture of coolant and distilled water. When coolant flows out of drain hole, close petcock.
  2. Add coolant mixture to air charge cooler until full. Remove charge air cooler pump relay located near coil assembly. Turn ignition on. Install jumper wire between charge air cooler relay terminals "A" and "B" to operate charge air cooler pump.
  3. While pump is operating, add coolant mixture to system until system is full. Install charge air cooler pressure cap.