Momentary Minor Irregularity In Engine Output - Mazda B-Series 1997 Workshop Manual

TROUBLESHOOTING GUIDE
FT
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11
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SURGES
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ACCELERATIONICRUISE
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DESCRIPTION
Momentary minor irregularity in engine output
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STEP
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INSPECTION
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ACTION
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Are any diagnostic trouble codes displayed during
Key On Engine Off, Key On Engine Running or
Continuous Memory inspection?
-
page FT-71
Yes
No
Diagnostic trouble code displayed
Check for cause (refer to Diagnostic Trouble Code
chart)
- -
=
page FT-77
No
diagnostic trouble codes displayed
Go to next step
Disconnect vacuum hose from EGR valve and plug
it.
Is drive symptom eliminated?
Yes Check EGR vent on vacuum hose to EGR valve for
obstruction or leak
If OK, replace EGR vacuum regulator solenoid
If not OK, repair or replace
Go to next step
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Yes
1
Go to next step
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3
Check EGR valve and EGR vacuum regulator
solenoid
=
page FT-158,159
Does EGR valve seat properly?
Remove PCV valve and shake it.
Does PCV valve rattle? Go to next step
Start engine. Disconnect crankcase ventilation
from thethrottle body. Place a stiff piece of paper
No
Check
evaporitive
emission
over the hose end.
Does vacuum hold the paper?
P G G a t i v e hose and phce a stiff piece of
.
.
Does vacuum hold paper?
If yes, check evaporative ernission system
=
page FT-160
If no, check for vacuum leak in PCV system, oil
cap, PCV valve, rocker cover for bolt torquelgasket
leak
Perform Fuel Line Pressure Inspection.
=
page FT-150
Is fuel line pressure correct?
Yes Go to next step
--
Zero or low:
Check pressure regulator diaphragm
=
page FT-154
Check fuel pump circuit
-
page FT-151
High:
Check pressure regulator for high pressure cause
-
page FT-154
Check for clogged fuel return line
Go to next step
Fuel line pressure:
240-280 kPa (2.5-2.8 kgflcrn*, 35-40 psi)
Visually look for fuel leakage at injector O-ring,
pressure regulator, and fuel line. Service as
necessary.
Perform Fuel Pressure Hold Inspection.
=
page FT-150
Does fuel line pressure hold?
Yes
Check pressure regulator diaphragm condition
=
page FT-154
If condition is OK, check injector
page FT-155
If condition is not OK, replace pressure regulator
Crank engine for 5 seconds. Does pressure drop
more than 34 kPa (0.35 kgf/cma, 5 psi) by the end
of 5 second crank cycle?
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8
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Disconnect inertia fuel shutoff switch connector.
Check resistance of injector(s) at PCM connector
If resistance is OK, check as follows:
Injector drive s i ~ n a l
lnjector flow rate
PCM
If resistance is not OK, check for open in injector
clrcuit
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Yes
1
Go to next s t e ~
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