Table of Contents
Advertisement
and pressurize t h e system. I f t h e gauge reads 100
K p a ± 7 K p a (14.5 p s i ± 1 psi), pressure i s correct
and f u r t h e r testing i s n o t r e q u i r e d . R e i n s t a l l fuel
hose u s i n g a new o r i g i n a l equipment type clamp, a n d
t i g h t e n to 1 N»m (10 in-lbs.) torque. I f pressure is not
correct, record t h e pressure a n d continue w i t h test
procedure.
(4) I f fuel pressure i s below specifications, i n s t a l l
tester i n the fuel supply line, between the fuel t a n k
and fuel filter a t the rear of vehicle.
(5) Repeat test. I f pressure is 5 psi higher t h a n pre-
v i o u s l y recorded pressure, replace fuel filter. I f no
change is observed, gently squeeze r e t u r n hose. I f
pressure increases, replace pressure regulator. I f no
change
is observed,
problem is either a plugged
p u m p filter (sock) or defective fuel pump.
(6) I f pressure is above specifications, remove t h e
fuel r e t u r n l i n e hose from t h e chassis line a t fuel
t a n k and connect a 3 foot piece o f fuel hose t o the re-
t u r n line. P u t t h e other end i n t o a n approved gaso-
l i n e container ( m i n i m u m 2 g a l l o n size) so t h a t a l l
r e t u r n fuel w i l l flow i n t o container. Repeat test. I f
pressure is now correct, check i n - t a n k r e t u r n hose for
k i n k i n g . Replace fuel p u m p assembly i f i n - t a n k res-
e r v o i r check valve or aspirator j e t is obstructed. (This
test should be performed w h e n fuel t a n k is 1/2 f u l l or
greater.)
(7) I f pressure is s t i l l above specifications, remove
fuel r e t u r n hose from t h r o t t l e body. Connect a substi-
t u t e hose t o the t h r o t t l e body r e t u r n nipple a n d place
other end o f hose i n clean container. Repeat test. I f
pressure is now correct, check f o r restricted fuel re-
t u r n line. I f no change is observed, replace fuel pres-
sure regulator.
MECHANICAL
MALFUNCTIONS
Mechanical malfunctions are more difficult t o diag-
nose w i t h t h i s system. The Single Board E n g i n e Con-
t r o l l e r (SBEC) has been programmed t o compensate
for some mechanical malfunctions such as incorrect
cam t i m i n g o r vacuum leaks. I f engine
performance
problems are encountered, and n o f a u l t codes are dis-
played, t h e problem m a y be mechanical r a t h e r t h a n
electronic.
FUEL PUMP MODULE
The fuel pump module is i n s t a l l e d i n the top of the
fuel t a n k (Fig. 3 ) . I t contains t h e fuel p u m p , fuel
p u m p reservoir, i n - t a n k fuel
filter,
pressure relief/
rollover valve, electrical connector for the fuel pump
gauge sending u n i t , fuel filler vent, fuel supply and
r e t u r n tube connections, and t h e fuel d r a i n tube nip-
ple.
Fig. 3 Top View of Fuel Pump
Module
REMOVAL
WARNING: THE TBI FUEL SYSTEM IS UNDER A
CONSTANT PRESSURE OF APPROXIMATELY 100
KPA (14.5 PSI). BEFORE SERVICING
THE FUEL
PUMP MODULE THE FUEL SYSTEM PRESSURE
MUST BE RELEASED.
(1) D r a i n t h e fuel t a n k . Refer t o " D r a i n i n g F u e l
T a n k " i n t h i s group.
(2) Remove fuel t a n k . Refer to " F u e l T a n k s " i n t h i s
group.
( 3 ) W h i l e holding t h e fuel p u m p module down, re-
move the h o l d i n g clamp (Fig. 4 )
(4) Release t h e module. I t w i l l s p r i n g u p from i t s
position.
(5) Remove module f r o m fuel t a n k .
Fig. 4 Fuel Pump Module
Removal/Installation
Advertisement
Table of Contents
