Ford Corsar Repair Manual page 206

TROUBLE DIAGNOSES
DIAGNOSTIC PROCEDURE 4
-
FUEL DELIVERY SYSTEM
Note: Before consulting this chart ensure there is sufficient fuel in the tank.
probe fuel pump test circuit AF66 with
test light to earth.
lgnition "off" for 10 seconds.
Go to Diagnostic Procedure
3.
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apply + l 2 volts to fuel pump by bridging ckt A105
to AF66 on fuel pump relay plug. Ignition "on".
1
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Listen for fuel pump running at fuel tank.
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Is pump running?
'NOTE: It is normal for the
pressure to drop slightly after the
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pump stops running, but should
Yes No
then hold steady and drop no
furthe,:
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I If the engine is hot when this
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(1)
-
lgnition "off", remove + l 2 volts to fuel pump (Remove Bridge).
(2)
-
Disconnect fuel pump electrical connector. Crank engine for 10 seconds
to relieve any residual fuel pressure.
(3)
-
lgnition "off'', connect fuel pressure gauge to hose between fuel rail
and filter, reconnect pump electrical connector.
pressure test is performed. It is OK
if the pressure very slowly begins
to rise after the pump stops.
(4)
-
Remove vacuum hose from pressure regulator.
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(5)
-
lgnition "on'', apply bridge to ckt A105 & AF66 on relay and allow pump to
run 1 minute. This is to purge the lines of any air before pressure testing.
1
(6)
-
lgnition "off" for 10 seconds. Remove bridge from fuel pump relay.
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(7)
-
Observe fuel pressure when ignition is turned "on".
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(8)
-
Pressure should be 280-320 kPa. & not continue to d r o ~ after pump stops
r u n n i n ~ . (Pump should run about 3 seconds, then shut off.) See *Note Above.
Ok
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*Ilgnition ''on7', connect
+ l 2 volts to fuel pump
Pressure, but
continues to drop
after pump stops.
Ignition "off" for 10 seconds.
while you observe the pressure gauge, have
a helper turn the ignition "on".
When the pump stops running (after 3 seconds),
while the pressure is dropping, pinch shut
the fuel hose.
Pressure now holds??
Check for leaks
in the
"Pressure-Side"
of the fuel
system. If ok,
replace fuel
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(Bridge ckt A105 & AF66 on
relay plug).
and note fuel pressure.
Connect a hand vacuum
pump to the regulator
vacuum fitting and apply
50 kPa (15" Hg) vacuum to
the regulator.
Note fuel pressure with
vacuum applied to
regulator. It should be
at least 15 kPa
& S
than
when no vacuum was
applied.
Is it?
No trouble found.
Ensure vacuum hose
between regulator
connected, has no
splits or kinks and
is not restricted.
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Replace
Pressure
regulator.
and intake plenum is
Replace
pressure
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Ignition "off" for 10 seconds.
while you observe the
pressure gauge, have a
Go to
@
on following page.
Pump.
Locate and replace
Leaking injectors.
helper turn the ignition "on".
When the pump stops running
(after 3 seconds) and while the
pressure is dropping, pinch
shut the pressure (supply)
regulator.
Check for:
-
Fuel pressure line restricted
between pump and fuel rail.
-
Fuel supply line between tank
hose at the fuel rail.
and pump either restricted -or-
leaking (sucking air).
Pressure now holds??
- Restricted fuel filter.
-
Restricted in-tank fuel strainer.
Yes
No
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