5.22
Section 5
EFI Fuel System
Throttle Body/Intake Manifold Assembly
Figure 5-21. Purge Port Location.
General
The vent hose assembly is intended to vent fuel vapor
out of the fuel pump module and direct the fuel vapor
into the thro le body. All EFI engines are equipped
with an engine mounted purge port on the #2 cylinder
barrel baffl e. This capped purge port can be used by
the OEM to vent fuel tanks or used in conjunction
with a carbon canister kit for Tier III evaporative
emissions compliance. The purge port connects to
the vent hose assembly and directs all fuel vapor into
the thro le body. If the purge port remains unused,
the port must remain capped to prevent dirt from
entering the engine. See Figure 5-21.
Service
No specifi c servicing is required for the vent hose
assembly or purge port unless operating conditions
indicate replacement is required. All components
are serviced individually. Abrasion sleeves on hoses
should be reused or replaced when servicing vent
hoses. Please note vent hose routing and replicate
a er service or component replacement to prevent
pinching or abrasion of the vent hoses.
Service
The high pressure fuel line is mounted to the
intake manifold. No specifi c servicing is required
unless operating conditions indicate that it needs
replacement. It can be detached by removing the two
mounting screws, wire ties, and the injector retaining
clips. Thoroughly clean the area around all joints and
relieve any pressure before starting any disassembly
by following the instruction on page 5.2.
Purge Port and Vent Hose Assembly
Purge Port
Figure 5-22. Throttle Body/Intake Manifold Details.
General
The EFI engines have no carburetor, so the thro le
function (regulate incoming combustion airfl ow) is
achieved with a thro le valve in a separate thro le
body a ached to the intake manifold. The thro le
body/intake manifold provides mounting for the
fuel injectors, thro le position sensor, intake air
temperature sensor, high pressure fuel line, idle speed
screw, and air cleaner assembly. See Figure 5-22.
Service
The thro le body is serviced as an assembly, with
the thro le sha , TPS, thro le plate, and idle speed
adjusting screw installed. The thro le sha rotates on
needle bearings (non-serviceable), capped with seals
to prevent air leaks.
NOTE: ECU Reset is required if the thro le body is
replaced.
Idle Speed Adjustment (RPM)
Idle Speed
Adjustment
Screw
Figure 5-23. Idle Speed Adjustment.
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