How to do a Compression Test
A compression test is an easy way to determine the internal health of your engine. You can pay a dealership $50 to do it for you, or you can do it yourself in about 10-15 minutes. Here's how...
You can get a compression tester for between $15 and $50 almost anywhere you can get auto supplies, including Auto Zone, Pep Boys, and even Wal-Mart. You don't need a particularly good or expensive one just to make sure you're in specification.
Matco tools, model # CT166K
In case any of the plugs are fouled. The NGK are the most frequently recommended plugs on the Honda motors, if you're not replacing your plugs, and even if you are, you might as well make sure they're properly gapped.
Instructions:
1. Before you begin, make sure the battery is fully charged and engine is up to normal operating temperature.
2. Unplug Electrical Fuel Injector connections individually
3. Unplug the coil connector, it’s on the left side of the engine, Connected to the Distributor
4. Remove all 4 plugs and examine them carefully for signs of a problem. If your valve seals are bad in any cylinder, the plug will be fouled to some degree. Signs of oil on the plugs could indicate a ring problem
5. Screw the compression gauge into the spark plug hole
6. Open the throttle plate, and keep it at WOT (wide open throttle) for as long as you’re cranking.
7. Turn the ignition to the ON position, and hold it there for a count of five revolutions (do not turn the key on-and-off four times). On each rotation, the gauge needle will jump slightly less than the previous
Note: If your battery is weak, the engine will turn over slower and give you lower readings. Recharge the battery and redo the test
8. The last number the gauge jumps to is the compression for that cylinder.
Note: For photography and freezing cold reasons I only Cranked the engine 2 times, reason for the 99.8 PSI reading
9. Repeat for each cylinder.
Standard PSI:
Diagnose:
When doing the tests make note of the readings for each cylinder, all the readings should be in a range of %10 +- any reading below indicates a possible leak, if so next steps would be a wet compression test and leak down test
A compression test is an easy way to determine the internal health of your engine. You can pay a dealership $50 to do it for you, or you can do it yourself in about 10-15 minutes. Here's how...
You can get a compression tester for between $15 and $50 almost anywhere you can get auto supplies, including Auto Zone, Pep Boys, and even Wal-Mart. You don't need a particularly good or expensive one just to make sure you're in specification.
Matco tools, model # CT166K
In case any of the plugs are fouled. The NGK are the most frequently recommended plugs on the Honda motors, if you're not replacing your plugs, and even if you are, you might as well make sure they're properly gapped.
Instructions:
1. Before you begin, make sure the battery is fully charged and engine is up to normal operating temperature.
2. Unplug Electrical Fuel Injector connections individually
3. Unplug the coil connector, it’s on the left side of the engine, Connected to the Distributor
4. Remove all 4 plugs and examine them carefully for signs of a problem. If your valve seals are bad in any cylinder, the plug will be fouled to some degree. Signs of oil on the plugs could indicate a ring problem
5. Screw the compression gauge into the spark plug hole
6. Open the throttle plate, and keep it at WOT (wide open throttle) for as long as you’re cranking.
7. Turn the ignition to the ON position, and hold it there for a count of five revolutions (do not turn the key on-and-off four times). On each rotation, the gauge needle will jump slightly less than the previous
Note: If your battery is weak, the engine will turn over slower and give you lower readings. Recharge the battery and redo the test
8. The last number the gauge jumps to is the compression for that cylinder.
Note: For photography and freezing cold reasons I only Cranked the engine 2 times, reason for the 99.8 PSI reading
9. Repeat for each cylinder.
Standard PSI:
nominal 178 psi
minimal 135 psi
max variation 28 psi
Diagnose:
When doing the tests make note of the readings for each cylinder, all the readings should be in a range of %10 +- any reading below indicates a possible leak, if so next steps would be a wet compression test and leak down test
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