Pontiac Fiero 1988 Service Manual page 605

6E3-A-22 DRIVABILITY AND EMISSIONS - FUEL INJECTION (PORT)
RETURN LINE
7 =
=
—
FLEX HOSE
8-8-84
5 19-87 5 S 1 2 8 8 - 6 E
CHART A-7
(Page 4 of 4)
FUEL SYSTEM DIAGNOSIS
2.8L "P" SERIES (PORT)
Test Description:
Numbers below refer to circled
numbers on the diagnostic chart.
1. Pressure but less than 280 kPa (40.5 psi) falls into
two areas:
• Regulated pressure but less than 280 kPa
(40.5 psi) Amount of fuel to injectors OK but
pressure is too low. System will be lean
running and may set Code 44. Also, hard
starting cold and overall poor performance.
• Restricted flow causing pressure drop -
Normally, a vehicle with a fuel pressure of less
than 165 kPa (24 psi) at idle will not be
driveable. However, if the pressure drop
occurs only while driving, the engine will
normally surge then stop as pressure begins to
drop rapidly.
2. Restricting the the fuel return line allows the fuel
pump to develop its maximum pressure (dead head
pressure). When battery voltage is applied to the
pump test terminal, pressure should be above 414
kPa.(60 psi)
3. This test determines if the high fuel pressure is
due to a restricted fuel return line or a pressure
regulator problem.