Engine Compression Test
Special Tools
EN-48248 Cylinder Compression Pressure Gauge
For equivalent regional tools, refer to
Special Tools .
| 1. |
Ensure that the vehicle's
batteries are in good condition, and fully charged. |
| 2. |
Operate the vehicle until the
engine is at normal operating temperature. |
| 4. |
Disconnect the crankshaft
position sensor. |
| 5. |
Remove the fuel pump relay
from the underhood fuse block. |
| 6. |
Remove all 4 fuel injectors.
All 4 fuel injectors must be removed from the engine during each
cylinder test to obtain valid test results. |
|
Note: The engine
cranking time for the compression test should be less then 10
seconds and at 30 second intervals.
|
| 7. |
Crank the engine with the
starter motor for 5 seconds to remove any foreign substances from
the cylinders. |
| 8. |
Prior to taking a compression
reading, verify the cranking speed is greater than 140 RPM. If the
cranking speed is below 140 RPM, repair the slow cranking speed
condition before continuing with the compression test. |
| 9. |
Install EN-48248
gauge in the fuel injector hole for the cylinder that is
being checked. |
| 10. |
Using the vehicle's starter
motor, rotate or crank the engine for 4 compression strokes, puffs,
for the cylinder being tested. |
| 11. |
Observe the compression gauge
and note the reading as the compression test is being performed. A
normal cylinder reading will be indicated if compression builds up
quickly and evenly to the specified level. An abnormal reading will
be indicated if compression is low on the first compression stroke,
starts increasing on the following compression strokes but does not
reach the specified level. |
| 12. |
Record the compression reading
for the cylinder just tested. |
| 13. |
Disconnect the compression
gauge from the fuel injector hole. |
| 14. |
Repeat steps 9-13 for all
remaining cylinders. All 4 cylinders must be tested to obtain valid
test results. Record the readings. |
| 15. |
The normal compression in any
one cylinder is 2.600 kPa (377 psi) . There should
not be more than 260 kPa (37 psi) difference
between a suspect cylinder and the average compression of all 4
cylinders. |
| |
• |
Normal - Compression builds up
quickly and evenly to the specified compression for each
cylinder. |
| |
• |
Piston rings leaking -
Compression is low on the first stroke. Compression builds up with
the following strokes but does not reach normal. |
| |
• |
Valves leaking - Compression
is low on the first stroke. Compression usually does not build up
on the following strokes. |
|
