Intake Valve Deposit Rating System - Ford LRG-423 Service Manual

01-12 Engine Service
01-l 2
SERVICE PROCEDURES (Continued)
remove than carburetor deposits. IVD must be
COMPLETELY removed to restore cold start and
normal engine performance.
CAUTION:The overuse of cleaning fluids may
cause engine damage not covered under warranty.
CAUTION: Only walnut shell blasting using
Rotunda 014-00975 Carbon Blaster and
Automotive Borescope, or equivalent, is
recommended for removing carbon from engine
valves with the engine assembled. Other abrasives
may cause engine damage on start-up if not
completely removed.
1. Perform engine inspection of vacuum lines and
wiring.
2. Perform normal engine diagnostics. Check fuel
and ignition systems.
3. If normal diagnostics have not resolved the
engine performance concerns, proceed with the
following IVD inspection steps.
4. Remove any two spark plugs (12405).
5.
CAUTION: Do not bump the engine with the
remote starter switch or ignition switch with
the borescope in the spark plug hole or
Intake Valve Deposit Rating System
attempt to view the valve while rotating the
engine. Damage to the borescope or engine
may result.
Use a remote starter switch to bump the engine
over until the intake valve (6507) is fully open in
the cylinder to be inspected.
6.
CAUTION: Do not power the borescope light
source from a vehicle battery (10655) while it
is being charged. For example, if the engine is
running or the battery (10655) is connected to
a charger, the lamp may fail.
Using the Rotunda Carbon Blaster and
Automotive Borescope 014-00975, or equivalent
automotive borescope, inspect the backside of
the intake valves (6507) through the spark plug
holes for the presence of carbon deposits.
Compare the deposits with the deposit rating
system chart. If any of the intake valves (6507)
appear to have a carbon deposit level of 7 or less
(lower number rating), intake valve cleaning is
required. If no carbon deposits are seen or the
deposit level is 8 or cleaner, the drive concern
may be the result of low volatility fuel.
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