Pontiac Fiero 1988 Service Manual page 693

6E3-C7-2 D R I V E A B I L I T Y
AMD
EMISSIONS -
FUEL INJECTION (PORT)
[ T l E G R V A L V E
f T ] E X H A U S T G A S
f T ] I N T A K E A I R
f T ]
V A C U U M PORT
ITl
D I A P H R A G M
[ ~ 6 ~ 1
V A L V E OPEN
fTI
V A L V E C L O S E D
f T ] SPRING
45 0536-6E
Figure CJ~? - Port E G I Waive
• Negative backpressure exhaust gas recirculation
(EGR) valves will have an "N" stamped on the top
side of the valve after the part number.
• Positive backpressure EGR valves will have a "P"
stamped on the top side of the valve, after the part
number.
When replacing an EGR valve, always check for
correct part number in the parts catalog or
supplemental bulletin.
c
B T
T
1
7
0 8
3
8
2 1
3
4
1 2 1
< I
3
4
1 2 1
1. ASSEMBLY PLANT CODE
2. PART NUMBER
3. DATE BUILT
4. LOOK HERE FOR LETTER:
P = POSITIVE BACK PRESSURE
N = NEGATIVE BACK PRESSURE
BLANK = PORTED VALVE
* 4S 0538-6E
2-27-87
Figure C7-3 - EGR
Valve Identification
RESULTS OF INCORRECT OPERATION
Too much EGR flow tends to weaken combustion,
causing the engine to run roughly or stop and any of
the following could happen:
• Engine stops after cold start.
• Engine stops at idle after deceleration.
• Car surges during cruise.
• Rough idle.
If the EGR valve should stay open all of the time,
the engine may not idle.
Too little or no EGR flow allows combustion
temperatures to get too high during acceleration and
load conditions. This could cause:
• Spark knock (detonation).
• Engine overheating.
• Emission test failure.
A I R I N L E T L I N E
(TO A I R C L E A N E R
I N L E T A I R )
6 ^
" 1
PH
E G R V A C U U M C O N T R O L
A S S E M B L Y B A S E
fT]
E G R V A C U U M D I A G N O S T I C
C O N T R O L SWITCH
fT|
D I A G N O S T I C SWITCH C O N N E C T O R S
f T ] E G R S O L E N O I D
[T]
F I L T E R
[Tl
A I R I N L E T L I N E
SS1928-6E
Figure C7-4 - Electronic Vacuum Regulator Valve
DIAGNOSIS
A "Scan" tool will display the duty cycle being
commanded to the EGR solenoid by the electronic
control module (ECM). and also whether the
diagnostic switch is open or closed.
Diagnosis of the EGR system is covered in CHART
C-7A at the end of this section. If a code 32 has been
set, refer to Code Chart 32
ON-CAR SERVICE
EGR VALVE
Remove or Disconnect
4~*
1. Vacuum line
2. Bolts
3. EGR valve