B.
Honda Civic Ignition System Troubleshooting (Continued)
A summary of the tests that should be followed, if you are experiencing a "crank but won't start situation," are:
1. Check Engine Light (CEL) Tests. If the CEL does not go out, most Civics will not spark and the fuel pump will not run. Therefore, all efforts should first be directed to correcting the problem(s) that prevent you from being able to answer "Yes" to the three basic diagnostic questions below:
a. Turning the ignition switch to ON (or position II), not START, does the CEL come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) 15 amp fuse, in the under-dash fuse/relay box; ECM (perform the
K-Test; Main Relay; or the Ignition Switch. Perform tests in that order.
b. When the CEL goes out, do you hear and/or feel the Main Relay "click"? If not, repair or replace the Main Relay.
c. During the 2 second interval that the CEL is on, do you hear the fuel pump in the gas tank run? If not, check that the fuel pump works by jumping terminals 5 and 7 on the main relay connector and then turning the ignition switch to ON.
2. Fuse Tests. Check all under-hood and under-dash fuses with a test light or multi-meter. Using a test light or multi-meter is faster, more accurate, and eliminates the possibility of replacing a fuse in the wrong slot. This is easy to do in the dark and cramped location of most under-dash fuse boxes.
3. Diagnostic Trouble Code (DTC) Test. Jump the 2-P Service Check Connector with a paper clip, turn the ignition switch to ON (or position II), and read DTCs, if any.
4. Spark Tests. Perform the standard spark test; i.e., remove a spark plug wire and attach it to a properly gapped spark plug, touch the plug to a convenient ground, and observe the spark, while someone cranks the engine. Look for a good, solid spark. It's preferable to use a calibrated ignition tester, such as KD Tools No. 2756. Do this for each plug. If none of the plugs spark:
a. Tachometer Test. Disconnect tachometer wire (if equipped). A shorted tachometer can prevent the vehicle from starting. The blue wire going to the Ignition Control Module (igniter) should be unfastened. Try starting the car again. If it starts, the problem is with the tachometer. If it still doesn't start:
b. Power to Distributor Test. Turn ignition OFF. Disconnect the 2-P connector from the distributor. Turn the ignition switch ON. Measure voltage between BLK/YEL (+) terminal and body ground. There should be 12+ volts read. If not, repair open in BLK/YEL wire between the 2-P connector and ignition switch.
c. ICM (igniter) Test. Characteristics of a bad igniter are no spark (dead engine) or fluctuating rpm.
1. Remove distributor cap, rotor, and leak cover.
2. Disconnect the BLK/YEL, WHT/BLU, YEL/GRN, and BLU wires from the ICM.
3. Turn the ignition switch ON. Check for voltage between the BLK/YEL wire and body ground. There should be battery voltage. If there is no voltage, check the BLK/YEL wire between the ignition switch and the ICM. If there is voltage, go to step 4.
4. Turn ignition switch ON. Check for voltage between the WHT/BLU wire and body ground. There should be battery voltage. If there is no battery voltage, check the ignition coil and the WHT/BLU wire between the ignition coil and the ICM. If there is battery voltage, go to step 5.
5. Check the YEL/GRN wire between the ECM and the ICM.
6. Check the BLU wire between the tachometer and the ICM.
7. If all test are normal, replace the ICM.
d. Coil Test.
1. Remove the two screws to disconnect the BLK/YEL and WHT/BLU wires from terminals A (+) and B (-), respectively.
2. Measure resistance (ohms) between the terminals. Replace coil if the resistance is not with specifications. Primary Winding Resistance (between A and B terminals) should be 0.6 to 0.8 ohms. Secondary Winding Resistance (between A and secondary winding terminals) should be 12.8 to 19.2 k-ohms.
Autozone and O'Reilly Auto Parts will test igniters and coils for free.
5. Fuel Test. For the fuel injectors to work properly, the fuel rail must receive fuel at the proper flow and pressure. To test fuel pump pressure:
a. Disconnect negative battery cable.
b. Remove gas cap, in order to depressurize the system.
c. Remove the 6 mm service bolt at the fuel filter, while holding the banjo bolt with another wrench.
d. Place shop towel over the service bolt.
e. Loosen the service bolt one complete turn, to depressurize the fuel filter.
f. Install fuel pressure gauge and check for 40 to 47 psi. If engine will not start, turn the ignition switch on, wait for two seconds, turn it off, then back on again and read the fuel pressure. If pressure is low, check for a clogged fuel filter, faulty fuel pressure regulator, or leakage in the fuel hoses or pipes. As a last resort, replace the fuel pump.
Note: I am not a real fan of DIY bench testing of main relays, ICMs, and coils. DIY bench testing does not simulate the heat that often causes these components to exhibit intermittent failure. It's safer to replace these critical ignition system components. Remember, the objective is "like new" performance and reliability, for as long as you own the car.