Ignition System: Service Precautions
***UPDATED BY TSB# 24 89 03, FEB. 89WARNING! SPECIAL PRECAUTIONS
Some extra precautions are necessary when servicing DIGIFANT II equipped vehicles. The electronic control unit (ECU) will be electronically damaged when the following conditions are present:
1. Shorting out ignition terminal #1 (on the ignition coil) to ground during engine adjustment. (A method used on cars with breaker point type ignition systems to kill the engine).
2. A floating ground connection to the ECU's terminals #13 and #19. Check for a good ground connection at:
a. Intake manifold
b. Cooling outlet fitting at the engine block
c. Negative post of the battery
3. Disconnecting the idle control valve while the engine is running.
4. Measuring current draw (mA) of the idle control valve with a digital multimeter set on the voltage scale.
STANDARD PRECAUTIONS
1. Do not touch disconnected high tension wire when cranking engine.
2. Do not disconnect ignition system wiring with ignition switched ON.
3. Connect or disconnect test equipment only when ignition system is switched OFF.
4. Do not connect any condenser to ignition coil terminal No. 1.
5. Do not crank engine unless high tension coil wire is disconnected at distributor cap and connected to ground.
6. When replacing the coil, do not use a standard ignition coil. Use only the specified electronic ignition coil.
7. Do not connect a test instrument with a 12 volt power supply to terminal 15 of the ignition coil.
8. Do not disconnect the battery while the engine is running.
9. Use only a distributor rotor with a resistance of 600-1400 Ohms.
10. If radio interference is a problem, use only 1,000 Ohm secondary ignition cable suppressor and a 1,000-5,000 Ohm spark plug connectors to resolve the problem.
11. Do not leave a quick charger on for more than one minute, or allow charging voltage to exceed 16.5 volts while charging or jump starting the vehicle.
12. Do not disconnect secondary ignition leads with engine running, or while cranking engine, except as instructed during test procedures.
13. Procedures must be followed as outlined, and components found defective must be replaced before proceeding with further tests.
14. Before testing system, check wiring harness for breaks, frayed insulation and proper routing, check that connectors are seated and free from corrosion and making good contact. Repair as needed.