Chrysler Stratus RHD 1999 Electronic Service Manual page 764

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DIAGNOSIS AND TESTING
CYLINDER COMBUSTION PRESSURE
LEAKAGE TEST . . . . . . . . . . . . . . . . . . . . . . . 10
CYLINDER COMPRESSION PRESSURE TEST . . 9
ENGINE DIAGNOSIS—MECHANICAL . . . . . . . . . 13
ENGINE DIAGNOSIS—PERFORMANCE . . . . . . 12
DIAGNOSIS AND TESTING
GENERAL INFORMATION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either
mechanical (e.g., a strange noise), or performance
(e.g., engine idles rough and stalls).
Refer to the Service Diagnosis—Mechanical Chart
and the Service Diagnosis—Performance Chart, for
possible causes and corrections of malfunctions. Refer
to Group 14, Fuel System, for the fuel system diag-
nosis.
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can-
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following:
• Cylinder Compression Pressure Test
• Cylinder Combustion Pressure Leakage Test
• Engine Cylinder Head Gasket Failure Diagnosis
• Intake Manifold Leakage Diagnosis
INTAKE MANIFOLD LEAKAGE DIAGNOSIS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water (Spray Bottle) at
the suspected leak area.
(3) If engine RPM'S change, the area of the sus-
pected leak has been found.
(4) Repair as required.
ENGINE DIAGNOSIS
INDEX
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CYLINDER COMPRESSION PRESSURE TEST
can be utilized to diagnose several engine malfunc-
tions.
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
operating temperature. Select a route free from traf-
fic and other forms of congestion, observe all traffic
laws, and accelerate through the gears several times
briskly.
plugs are being removed, check electrodes for abnor-
mal firing indicators fouled, hot, oily, etc. Record cyl-
inder number of spark plug for future reference.
secure to good ground to prevent a spark from start-
ing a fire (Conventional Ignition System). For Direct
Ignition System DIS disconnect the coil connector.
compression check.
spark plug hole in cylinder head. Crank engine until
maximum pressure is reached on gage. Record this
pressure as #1 cylinder pressure.
inders.
100 psi and not vary more than 25 percent from cyl-
inder to cylinder.
compression pressures, repeat the compression test.
abnormally low reading on the second compression
test, it could indicate the existence of a problem in
the cylinder in question. The recommended com-
pression pressures are to be used only as a
guide to diagnosing engine problems. An engine
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 9
INSPECTION (ENGINE OIL LEAKS IN
GENERAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
INTAKE MANIFOLD LEAKAGE DIAGNOSIS . . . . . 9
LASH ADJUSTER (TAPPET) NOISE
DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
The results of a cylinder compression pressure test
Ensure the battery is completely charged and the
(1) Check engine oil level and add oil if necessary.
(2) Drive the vehicle until engine reaches normal
(3) Remove all spark plugs from engine. As spark
(4) Disconnect coil wire from distributor and
(5) Be sure throttle blade is fully open during the
(6) Insert compression gage adaptor into the #1
(7) Repeat the previous step for all remaining cyl-
(8) Compression should not be less than (689kPa)
(9) If one or more cylinders have abnormally low
(10) If the same cylinder or cylinders repeat an
ENGINE 9 - 9
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