Pontiac Fiero 1988 Service Manual page 537

6E2-C2-6 DRIVEABILITY AND EMISSIONS - FUEL INJECTION (TBI)
ON-CAR SERVICE
Fuel System Pressure Test
GENERAL SERVICE INFORMATION
CAUTION:
• To prevent personal injury or damage to the
vehicle as the result of an accidental start,
disconnect and reconnect the negative
battery cable before and after service is
performed. (Where Delco-Loc
t m
radio is
installed on Pontiac cars, refer to NOTICE in
beginning of Section "9A" to reactivate radio*)
• To minimize the risk of fire, and personal
injury, relieve the fuel system pressure before
servicing the fuel rail, or any of its fuel
handling components., (See "Fuel Pressure
Relief Procedure," below).
• Also, catch any fuel that leaks out when
disconnecting the fuel lines, by covering the
fittings with a shop cloth. Place the cloth in an
approved container when work is complete.
The TBI unit repair procedures cover component
replacement with the unit on the vehicle. However,
throttle body replacement requires that the complete
unit be removed from the engine.
Refer to the disassembled view (Figure C2-8) for
identification of parts during repair procedures.
Service repair of individual components is performed
without removing the TBI unit from the engine. If
removed, it is essential that care is taken to prevent
damage to the throttle valve or sealing surface while
performing any service.
Whenever service is performed on the TBI or any
of its components, first remove the air cleaner and air
cleaner gasket. Discard the gasket and replace it with
a new one before replacing the air cleaner after service
is complete.
Fuel Pressure Relief Procedure
On the 2.5L engine, the TBI Model 700 contains no
constant bleed feature to relieve pressure. Therefore,
the procedures listed below are required for relieving
fuel pressure.
1. Place transmission selector in Park (Neutral on
manual transmissions), set parking brake, and
block drive wheels.
2. Remove fuse for fuel pump.
3. Start engine and allow to run a few seconds until
it stops for lack of fuel.
4. Engage starter for three seconds to dissipate fuel
pressure in lines. Fuel connections are now safe
for servicing.
5. When pressure is relieved and servicing is
complete, return fuse to fuse block.
A fuel system pressure test is part of several of the
Diagnostic Charts and Symptom checks. To perform
this test, follow this procedure:
1. Turn engine "OFF" and relieve fuel pressure,
following instructions under "Fuel Pressure Relief
Procedure," above.
2. Remove air cleaner and gasket. Discard gasket.
3. Uncouple fuel supply flexible hose in engine
compartment. Install fuel pressure gage
J-29658/BT8205 and adapter 29658-85 between
the steel line and flexible hose.
4. Tighten gage in line to ensure no leaks occur
during testing.
5. Start car and observe fuel pressure reading. It
should be 62-90 kPa (9-13 psi); if not, refer to
CHART A-5 or A-7. • "
6. Relieve fuel pressure (see above instructions).
7. Remove fuel pressure gage.
8. Reinstall fuel line.
9. Start car and check for fuel leaks.
10. Install air cleaner with new gasket.
Cleaning and \& Inspection
All TBI component parts, with the exception of
those noted below, should be cleaned in a cold
immersion cleaner such as Carbon X (X-55) or
equivalent.
NOTICE:
The throttle position sensor (TPS), idle air
control (IAC) valve, pressure regulator
diaphragm assembly, fuel injector or other
components containing rubber, SHOULD
NOT be placed in a solvent or cleaner
bath. A chemical reaction will cause these
parts to swell, harden or distort. Do not
soak the throttle body with the above
parts attached. If the throttle body
requires cleaning, soaking time in the
cleaner should be kept to a minimum.
Some models have hidden throttle shaft
dust seals that could lose their
effectiveness by extended soaking.
1. Clean all metal parts thoroughly, and blow dry
with shop air. Be sure that all fuel and air
passages are free of dirt or burrs.
2. Inspect mating casting surfaces for damage that
could affect gasket sealing.
Thread Locking Compound
A service repair kit is supplied with a small vial of
thread locking compound, with directions for use. If
this material is not available, use Loctite 262, or GM
part number 10522624, or equivalent.