Dodge 2000 DURANGO Service Manual page 293

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DIAGNOSIS AND TESTING (Continued)
on the end of the metal tip. The silicone-dielectric-
varnish-compound applied to the rotor tip for radio
interference noise suppression, will appear charred.
This is normal. Do not remove the charred com-
pound. Test the spring for insufficient tension.
Replace a rotor that displays any of these adverse
conditions.
Fig. 11 Rotor Inspection—Typical
1 – INSUFFICIENT SPRING TENSION
2 – CRACKS
3 – EVIDENCE OF PHYSICAL CONTACT WITH CAP
4 – ROTOR TIP CORRODED
SPARK PLUG CABLES
Check the spark plug cable connections for good
contact at the coil(s), distributor cap towers, and
spark plugs. Terminals should be fully seated. The
insulators should be in good condition and should fit
tightly on the coil, distributor and spark plugs. Spark
plug cables with insulators that are cracked or torn
must be replaced.
Clean high voltage ignition cables with a cloth
moistened with a non-flammable solvent. Wipe the
cables dry. Check for brittle or cracked insulation.
On 3.9L V-6 and 5.2/5.9L V-8 engines, spark plug
cable heat shields are pressed into the cylinder head
to surround each spark plug cable boot and spark
plug (Fig. 12). These shields protect the spark plug
boots from damage (due to intense engine heat gen-
erated by the exhaust manifolds) and should not be
removed. After the spark plug cable has been
installed, the lip of the cable boot should have a
small air gap to the top of the heat shield (Fig. 12).
Fig. 12 Heat Shields—3.9/5.2/5.9L Engines
1 – AIR GAP
2 – SPARK PLUG BOOT HEAT SHIELD
TESTING
When testing secondary cables for damage with an
oscilloscope, follow the instructions of the equipment
manufacturer.
If an oscilloscope is not available, spark plug cables
may be tested as follows:
CAUTION: Do not leave any one spark plug cable
disconnected for longer than necessary during test-
ing. This may cause possible heat damage to the
catalytic converter. Total test time must not exceed
ten minutes.
With the engine running, remove spark plug cable
from spark plug (one at a time) and hold next to a
good engine ground. If the cable and spark plug are
in good condition, the engine rpm should drop and
the engine will run poorly. If engine rpm does not
drop, the cable and/or spark plug may not be operat-
ing properly and should be replaced. Also check
engine cylinder compression.
With the engine not running, connect one end of a
test probe to a good ground. Start the engine and run
the other end of the test probe along the entire
length of all spark plug cables. If cables are cracked
or punctured, there will be a noticeable spark jump
from the damaged area to the test probe. The cable
running from the ignition coil to the distributor cap
can be checked in the same manner. Cracked, dam-
aged or faulty cables should be replaced with resis-
tance type cable. This can be identified by the words
ELECTRONIC SUPPRESSION printed on the cable
jacket.
Use an ohmmeter to test for open circuits, exces-
sive resistance or loose terminals. If equipped,
remove the distributor cap from the distributor. Do
IGNITION SYSTEM 8D - 7