Range Rover P38
LAND ROVER V8
3
ADJUSTMENT
ENGINE TUNING - up to 99MY
Service repair no - 19.22.13
The position of the Idle Air Control (IAC) valve can be
checked using TestBook and adjusted if necessary
through the by-pass screw in the plenum chamber.
The bypass screw is covered by a tamper proof plug
which can be extracted using a self tapping screw.
Vehicles in certain markets are not fitted with oxygen
sensors or active catalytic converters. Certain
specification vehicles may have active catalytic
converters fitted, but do not use oxygen sensors. This
is referred to as an open loop catalyst system. All
vehicles without oxygen sensors must have the
exhaust CO content checked periodically using an
approved CO meter and adjusted if necessary using
TestBook.
On vehicles with open loop catalyst systems, exhaust
CO content must be checked upstream of the catalyst,
NOT at the tailpipe.
Preliminary Checks
1. Ensure that air filter and fuel filter elements are
in a serviceable condition.
2. Check air intake system, including vacuum pipes
and hoses for correct routing and freedom from
leaks and restriction.
3. Electrical connections must be secure and leads
correctly routed.
4. Check ignition system integrity using an
approved Engine Analyser.
Procedure
Vehicles without oxygen sensors:
5. Ensure exhaust gas analyser is warmed and
calibrated ready for use.
6. Non catalyst vehicles: Connect exhaust gas
analyser to tailpipe.
7. Disconnect purge valve pipe at charcoal
canister.
CAUTION: Do not disconnect purge valve
electrical multiplug.
Open loop catalyst vehicles:
8. Remove blanking plug from RH exhaust front
pipe, forward of the catalyst.
9. Fit sampling pipe and tighten securely.
CAUTION: Air leaks at the sampling pipe
will cause incorrect readings.
10. Connect exhaust gas analyser to sampling pipe.
NOTE: When refitting the blanking plug
apply nickel based grease to the thread.
