Toyota Camry 95 Distributor Coil Troubleshooting

Open the hood and set the prop rod. Disconnect the negative battery cable from the battery, using a ratchet and socket. Remove the lid of the air cleaner housing. Loosen the hose clamp that holds the air intake tube to the throttle body assembly, with a ratchet and socket. Remove the entire intake tube and filter housing lid from the engine, and place the assembly away from your work area.

Locate the ignition distributor, just below the upper intake manifold on the driver's side of the engine. Place tabs of masking tape on all of the ignition wires attached to the distributor. Mark the wires from 1 through 4, using the stamped numbers on the distributor as a guide, with a black marker. If the numbers are not present, use the numbers 1 through 4 from left to right on the engine, and mark each wire according to its position on the engine. Mark the center ignition wire with an X.

Remove the distributor cap mounting bolts with your ratchet and socket. Remove the cap from the distributor. Mark the position of the end of the distributor rotor in correlation with the distributor body. It is important that you put the rotor back on in the exact same position from where you removed it. Remove the ignition coil dust cover from inside the distributor, with a Phillips screwdriver or Torx bit hand driver.

Turn the dial indicator on your multimeter to the ohms setting. Insert the red probe from the meter onto the positive terminal, marked by the +, and the black probe onto the negative terminal, marked by the -, to test the primary winding on the coil. The measurement on a cold engine should be between 0.36 and 0.55 ohms. The measurement on a warm engine should be between 0.45 and 0.65 ohms. If the resistance measurement is not within these specifications, the coil is bad and needs to be replaced.

Insert the red probe from the multimeter onto the "+." Place the black probe onto the high tension post at the bottom center of the coil, and measure the secondary winding on the coil. The measurement should be between 9,000 and 15,000 ohms if the engine is cold. The measurement should be between 11,400 and 18,100 ohms if the engine is hot. If the measurement is not within these specifications, replace the coil.

Insert the rotor back onto the distributor, making sure to align the rotor with the mark you made during removal. Measure the air gap between the rotor and the ignition coil, using a feeler gauge set. The measurement between the rotor and coil should be between 0.0008 and 0.0016 -- in thousandths of an inch. If the measurement is not within these specifications, remove and replace the entire distributor.

Place the red probe of the multimeter onto the "Ne+" prong of the electrical connector, on the distributor. This is the farthest prong to the right. Place the black probe onto the next prong, which is the "Ne-" prong. Measure the resistance between the two prongs. The measurement should be between 370 and 550 ohms if the engine is cold and between 475 and 650 ohms if the engine is hot. If the measurement is not within these specifications, replace the entire distributor.

Place the red probe onto the "G+" prong of the electrical connector, on the distributor, which is the farthest prong to the left of the connector. Place the black probe onto the next prong to the right, which is the "G-" prong. Measure the resistance between the two prongs. The resistance should be between 185 and 275 ohms if the engine is cold and between 240 and 325 ohms if the engine is hot. If the measurement is not within these specifications, replace the entire distributor assembly.

Assembly of the coil and distributor is the opposite of the tear down process. Make sure you match the mark on the rotor with the housing mark. Tighten all screws so that they are snug, as applying torque may crack or damage the plastic parts. Install the ignition wires in the order that they were removed from the distributor cap.

Open the hood and set the prop rod. Remove the negative battery cable from the battery, with a ratchet and socket. Remove the two nuts on the front of the engine V-bank cover, which covers the ignition coils. Remove the cover from the engine.

Remove the electrical connector from a single coil. Measure the resistance between the two electrical connector prongs on the coil, using a multimeter on ohms setting. The resistance between the two prongs should be between 0.54 and 0.84 if the engine is cold, between 0.68 and 0.98 if the engine is warm. If the measurement you take is not within these specifications, remove and replace the ignition coil. Install the electrical connector if the coil is good.

Repeat Step 2 of this project to test the other three coils. Replace individual or all coils as needed. Reconnect the negative battery cable when you are finished testing or replacing the ignition coils. Tighten the battery cable snug, with a ratchet and socket.