Exam 27: Ignition System Diagnosis and Service

Preignition is the same as detonation.

An ohmmeter connected to the leads of a pickup coil in a DI ignition system reads 14 ohms of resistance. The reading indicates that the pickup coil ______.

Which of the following is NOT a cause of spark knock?

Test equipment for checking the primary circuit is being discussed. Technician A says a logic probe can be used. Technician B says a DMM can be used. Who is correct?

To minimize EMI interference, sensor wires should be routed away from _____.

Technician A removes plug wires by grasping the spark plug boot and gently twisting it off. Technician B uses a 13/16 in. deep thinwall socket to remove spark plugs. Who is correct?

An exhaust gas analyzer will show higher than normal ____________________ when ignition timing is not correct.

The slope of the spark line is a good indication of the ____________________.

Technician A says a loose ignition module mount can cause intermittent misfires or no-start conditions. Technician B says when installing a new ignition module, a small amount of heat conductive grease should be applied to the mounting surfaces. Who is correct?

An ignition control module may overheat if it is not securely mounted.

Leaner air/fuel mixtures ______.

Possible causes for a no-start condition on a coil-over-plug EI engine are being discussed. Technician A says a faulty crankshaft sensor may prevent the engine from starting. Technician B says a shorted ignition coil may be the cause. Who is correct?

Gapping the spark plug is only necessary on used spark plugs. New spark plugs have their gaps set at the factory.

The firing lines on an oscilloscope are all abnormally low. Technician A says the problem could be a faulty coil. Technician B says the problem could be a lean air/fuel mixture. Who is correct?

During a coil output test, the firing line shown on the oscilloscope pattern should exceed ______ volts.

The companion cylinder for #1 cylinder on a six-cylinder engine with a firing order of 153624 is cylinder # ____________________.

While discussing an ignition problem displayed on a scope primary ignition pattern, Technician A says a worn distributor drive gear can cause an erratic transistor ON signal. Technician B says if there are erratic voltage spikes at the transistor ON signal, the ignition module may be faulty. Who is correct?

Which of the following problems is NOT caused by a misfire?

A bad sensor ground may cause the same symptoms as a faulty sensor.

A no-start condition on an EI system is being discussed. Technician A says to use a test spark plug to determine whether the problem is in the ignition system. Technician B says that if a noid light is connected to the injector harness and it pulses while the engine is cranked, the triggering unit for the primary ignition circuit should be okay. Who is correct?