ECM SERVICE CAUTIONS & NOTES
| CAUTION | Static electricity can destroy integrated circuits within ECM. Before servicing ECM, ground yourself and work area to discharge stored electricity. |
| CAUTION | DO 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 11) |
Replacing ECM While Using 3M Anti-Static Mat. Scheme 11
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.
Model 700 TBI Unit
Place transmission gear selector in Park (Neutral on manual transmissions). 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.
Model 220 TBI Unit
| WARNING | Fuel pressure is relieved and drops to zero when ignition is turned off. To minimize the risk of fire and personal injury, cover area to be disconnected with a shop rag. |
Throttle Body Cover (Model 220)
Place throttle body on Holding Fixture (J-9789-118 or BT 30-15) to prevent damage to throttle valve. Remove screws holding cover to throttle body, noting location of 2 short screws. Remove throttle body cover. see scheme 3 Throttle body cover and pressure regulator are serviced as an assembly. DO NOT remove screws attaching pressure regulator to cover.
Purging Fuel System (Diesel)
- Park vehicle on a level surface. Place drain pan under drain hose to collect fuel. Open drain valve 3-4 turns. With fuel tank cap installed and using air nozzle, apply 3-5 psi (.21-.35 kg/cm 2 ) through fuel return hose at injection pump.
- Contaminated fuel will be forced out of tank via filter drain hose. Continue to drain fuel until clear fuel is observed. Entire fuel tank may have to be drained. Close drain valve. Install fuel return hose.
Note. If vehicle is equipped with dual tanks, perform purging procedure on each tank.
WATER-IN-FUEL
- Fuel filter should be drained every 5000 miles or when "WATER-IN-FUEL" warning light glows. Diesel fuel can damage asphalt and painted surfaces. Always place a drain pan under drain hose to collect fuel.
- Stop vehicle and turn engine off. Apply parking brake. Remove fuel tank cap. Open water drain valve 2-3 turns. Start and allow engine to idle for 2 minutes or until clear fuel is observed. Turn engine off and close water drain valve.
- Install fuel tank cap. If "WATER-IN-FUEL" warning light comes on after driving a short distance or if engine runs rough or stalls, a large amount of water may be present in fuel tank. Purge fuel system. See PURGING FUEL SYSTEM in ADJUSTMENTS in this article.
OXYGEN (O2) SENSOR
O2 sensor is mounted in the exhaust pipe just below the exhaust manifold. It is equipped with a permanent pigtail which must be protected from damage when the sensor is removed.