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AUTOMOTIVE REPAIR INFORMATION:
Obtaining the auto repair information and automotive parts you need to fix a faulty engine requires you to accurately identify the problem behind it. However, when the problem is barely visible, this can be much harder than it sounds. In the initial stages of troubleshooting it is important to gain diagnostic direction, especially when you are dealing with hard to identify engine issues. By following the steps to properly identify engine problems, you will become a better diagnostician and save yourself time and energy in the long run. The following information will guide you in how to become a better engine doctor, allowing you to get your customers the answers they need faster.
Motor Age outlines three tests you can perform that will indicate if the engine you are examining is having difficulties. These tactics may even help determine what is causing a particular problem. The first is an oldie but goodie checking the manifold vacuum. Next we encourage you to use a relative compression test. And last but not least, you should try reading the secondary ignition pattern.
MANIFOLD VACUUM TO TEST ENGINE HEALTH:
1. Connect your vacuum gauge to an intake vacuum port as close to the intake manifold as you can.
A running engine at idle should produce between 18 inches/Hg to 21 inches/Hg and the needle should remain steady.
Significantly lower readings or a gauge needle that bounces around are signs that further, more detailed tests should be done.
2. Snap the throttle to wide open and release a few times while watching the gauge. The needle should drop to roughly 5 inches/Hg or less, rebound quickly and surge past the idle reading, then fall as quickly back to the idle reading. Any delay in needle response can indicate a problem with airflow through the engine, usually in the exhaust.
3. If this doesnt work, hold the throttle at a constant 2,500 rpm. The gauge should read near the idle reading and stay there. Lowering vacuum readings while maintaining a steady rpm are another indicator of a restricted exhaust.