FIGURE 32-1 A spark tester looks like a regular spark plug with an alligator clip attached to the shell. This tester has a specified gap that requires at least 25,000 volts (25 kv) to fire. - PowerPoint PPT Presentation
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Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-1 A spark tester looks like a regular spark plug with an alligator clip attached to the shell. This tester has a specified gap that requires at least 25,000 volts (25 kv) to fire.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-2 A close-up showing the recessed center electrode on a spark tester. It is recessed 3/8 in. into the shell and the spark must then jump another 3/8 into the shell for a total gap of 3/4 in.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-4 Measuring the resistance of an HEI pickup coil using a digital multimeter set to the ohms position. The reading on the face of the meter is 0.796 kΩor 796 ohms in the middle of the 500- to 1,500-ohm specifications.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-5 An AC voltage is produced by a magnetic sensor. Most sensors should produce at least 0.1 volt AC while the engine is cranking if the pickup wheel has many teeth. If the pickup wheel has only a few teeth, you may need to switch the meter to read DC volts and watch the display for a jump in voltage as the teeth pass the magnetic sensor.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-7 (a) The low-resolution signal has the same number of pulses as the engine has cylinders. (b) A dual-trace pattern showing both the low-resolution signal and the high-resolution signals that usually represent 1 degree of rotation.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-8 A track inside an ignition coil is not a short, but rather it is a low-resistance path or hole that has been burned through from the secondary wiring to the steel core.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-9 A GM type 2 distributorless ignition system (DIS) can be checked by unplugging both spark plug wires from one ignition coil and starting the engine. The spark should be able to jump the 1-in.(25-mm) distance between the terminals of the coil. No damage to the coil (or module) results because a spark occurs and does not find ground elsewhere.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-10 Using a vacuum hose and a grounded test light to ground one cylinder at a time on a DIS. This works on all types of ignition systems and provides a method for grounding out one cylinder at a time without fear of damaging any component.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-12 Note where the high-voltage spark jumped through the plastic rotor to arc into the distributor shaft. Always check for a defective spark plug(s) when a defective distributor cap or rotor is discovered. If a spark cannot jump to a spark plug, it tries to find a ground path wherever it can.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-13 Carbon track in a distributor cap. These faults are sometimes difficult to spot and can cause intermittent engine missing. The usual cause of a tracked distributor cap (or coil, if it is distributorless ignition) is a defective (open) spark plug wire.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-16 Measuring the resistance of a spark plug wire with a multimeter set to the ohms position. The reading of 16.03 kΩ(16.030 ohms) is okay because the wire is about 2 feet long. Maximum allowable resistance for a spark plug wire this long would be 20 kΩ(20,000 ohms).
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-19 When removing spark plugs, it is wise to arrange them so that they can be compared and any problem can be identified with a particular cylinder.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-20 A spark plug thread chaser is a low-cost tool that hopefully will not be used often, but is necessary to use to clean the threads before new spark plugs are installed.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-21 Since 1991, General Motors engines have been equipped with slightly (1/8 in.or 3 mm) longer spark plugs. This requires that a longer spark plug socket should be used to prevent the possibility of cracking a spark plug during installation. The longer socket is shown next to a normal 5/8-in.spark plug socket.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-23 Spark plug removed from an engine after a 500-mile race. Note the clipped side (ground) electrode. The electrode design and narrow (0.025 in.) gap are used to ensure that a spark occurs during extremely high engine speed operation. The color and condition of the spark plug indicate that near-perfect combustion has been occurring.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-25 New spark plug that was fouled by a too-rich air–fuel mixture. The engine from which this spark plug came had a defective (stuck partially open) injector on this one cylinder only.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-26 A water spray bottle is an excellent diagnostic tool to help find a intermittent engine miss caused by a break in a secondary ignition circuit component.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-29 (a) Typical SPOUT connector as used on many Ford engines equipped with distributor ignition (DI). (b) The connector must be opened (disconnected) to check and/or adjust the ignition timing. On DIS/EDIS systems, the connector is called SPOUT/SAW (spark output/spark angle word).
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-30 Typical engine analyzer hookup that includes a scope display.(1) Coil wire on top of the distributor cap if integral type of coil; (2) number 1 spark plug connection; (3) negative side of the ignition coil; (4) ground (negative) connection of the battery.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-36 Raster is the best scope position to view the spark lines of all the cylinders to check for differences. Most scopes display the cylinder 1 at the bottom. The other cylinders are positioned by firing order above cylinder 1.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-37 Display is the only position to view the firing lines of all cylinders. Cylinder 1 is displayed on the left (except for its firing line, which is shown on the right). The cylinders are displayed from left to right by firing order.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-40 The relationship between the height of the firing line and length of the spark line can be illustrated using a rope. Because energy cannot be destroyed, the stored energy in an ignition coil must dissipate totally, regardless of engine operating conditions.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman
FIGURE 32-41 A dual-trace scope pattern showing both the power and the waste spark from the same coil (cylinders 1 and 6). Note that the firing line is higher on the cylinder that is under compression (power); otherwise, both patterns are almost identical.
Diagnosis and Troubleshooting of Automotive Electrical,Electronic, and Computer Systems, Fifth EditionBy James D. Halderman