Since the FSM says nothing, I wonder how much compression is typically measured on a new engine, and what can we expect as normal, after say 100 000 miles?
Since the FSM says nothing, I wonder how much compression is typically measured on a new engine, and what can we expect as normal, after say 100 000 miles?
Eggman (07-02-2019)
Thanks Cobrajet, already read that thread, but I was looking for something more precise.
Where does it say what pressure is normal for a new engine? What about the 3A90?
Maybe Fummins can report from his experience with 3A92's?
EDIT:
Found it, finally...
The FSM has a section in chapter 11A-16 called "compression pressure check"
COMPRESSION PRESSURE CHECK
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Disconnect the connector of the ignition coil, and then
remove all of the ignition coils and spark plugs (Refer to
GROUP 11B Generator and Ignition System P.11B-10).
3. Disconnect the all of the injector connectors.
CAUTION
Keep away from the spark plug hole when cranking.
If compression is measured with water, oil, fuel, etc.,
that has come from cracks inside the cylinder, these
materials will become heated and will gush out from the
spark plug hole, which is dangerous.
4. Cover the spark plug hole with a shop towel etc., and after
the engine has been cranked, check that no foreign material
is adhering to the shop towel.
5. Set compression gauge to one of the spark plug holes.
6. Cranking the engine with the accelerator pedal fully
depressed, measure the compression pressure.
Standard value [at engine speed of 250 r/min]: 1,410 kPa (205 psi)
Limit [at engine speed of 250 r/min]: Minimum 950 kPa (138 psi)
7. Measure the compression pressure for all the cylinders, and
check that the pressure differences of the cylinders are
below the limit.
Limit: Maximum 98 kPa (14 psi)
8. If there is a cylinder with compression or a compression
difference that is outside the limit, pour a small amount of
engine oil through the spark plug hole, and repeat the
operations in steps from 5 to 7.
(1) If the compression increases after oil is added, the cause
of the malfunction is a worn or damaged piston ring
and/or cylinder inner surface.
(2) If the compression does not rise after oil is added, the
cause is a burnt or defective valve seat, or pressure is
leaking from the gasket.
9. Connect all of the injector connectors.
Last edited by foama; 07-03-2019 at 07:26 AM.
What's compression?
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Eggman (07-03-2019)