1988 PONTIAC FIERO Service Repair Manual

6E3-C4-6 2.8L (VIN S) DRIVEABILITY AND EMISSIONS
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DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-C6-4
SECTION C6
AIR INJECTION REACTlON (A.I.R.) SYSTEM
MANUAL, TRANSMISSION ONLY
CONTENTS
............... GENERAL DESCRIPTION C6-1
........................ PURPOSE C6-1
........... A.I.R. PUMP OPERATION.. C6-1
................... AIR CONTROL.. C6-1
.......... Electric Air Control Valve C6-1
............... Deceleration Valve C6-2
... RESULTS OF INCORRECT OPERATION C6-2
........................ DIAGNOSIS C6-2
............. OPERATIONAL CHECKS C6-2
.................... A.I.R. Pump C6-2
GENERAL DESCRlPTlON
PURPOSE
These systems are used to reduce carbon monoxide
(CO), hydrocarbon (HC) and oxides of nitrogen (NO,)
emissions. They also heat up the catalytic converter
quickly "ON" engine start-up so conversion of exhaust
gases will start quickly.
A.I.R. PUMP OPERATION
The system (Figure C6-1) includes:
@ An Air Pump
The air pump is driven by a belt on the front of
the engine and supplies the air to the system.
Intake air passes through a centrifugal filter fan
at the front of the pump; where foreign materials
are separated from the air by centrifugal force.
@ A Control Valve
Air flows from the pump through an
ECM
controlled valve (called a control valve) through
check valves to either the exhaust ports or the
silencer (overboard).
@ Check Valves
The check valves prevent back flow of exhaust
into the pump in the event of an exhaust backfire
or pump drive belt failure.
@ Necessary Plumbing
AIR CONTROL
Electric
Air Control Valve (EAC)
................. Hoses and Pipes C6-2
............. Deceleration Valve.. C6-3
.................... Check Valve C6-3
.................... ON-CAR SERVICE C6-3
................... DRIVE BELT ... C6-3
............... A.I.R.PUMP.....,.. C6-3
............... AIR CONTROL VALVE C6-3
.................... CHECK VALVE C6-4
............ DECELERATION VALVE.. C6-4
................ PARTS INFORMATION C6-5
ELECTRIC AIR CONTROL 1 DECELTIMING CHAMBEF VALVE 1 DIVERT AIR TO AIR
~DECEL TIMING ASSEMBLY CLEANER
VERY HIGH VACUUM 1 AIR FROM PUMP
SIGNAL PORT 1 AIR TO EXHAUST PORTS
14~~c~R1cA~~~RM1NAL 1 PRESSURE RELIEF ~SOLENOID ASSEMBLY
4s 1020-6E
Figure C6-1 - Electric Air Control Valve
When the solenoid is energized, the valve will
perform like a standardized diverter valve. Air
from
the air pump is directed to the exhaust ports, unless
there is a great sudden rise in manifold vacuum due to
throttle deceleration.
The electric air control valve combines electronic
control with the normal diverter valve function. This
valve can be electronically controlled to provide divert
air under any driving mode.

6E3-C6-2 2.8L (WIN 5) DRIVEABILITY AND EMISSIONS
When the solenoid is de-energized, the pressurized
air from the air pump is allowed to enter the decel
timing chamber. This places sufficient pressure on
the metering valve diaphragm to overcome spring
tension, closing the
valve,causing air to divert to the
silencer.
At higher engine speeds, excess air is exhausted to
the silencer through the pressure relief valve. (Figure
C6-1)
Deceleration Valve
To help prevent backfiring during high vacuum
conditions a deceleration (gulp) valve is used to allow
air to flow into the intake manifold (shown in Figure
C6-2). This air enters the airlfuel mixture to lean the
rich condition created by high vacuum when the
throttle valve closes on deceleration.
The vacuum draws the deceleration valve
diaphragm down and opens the valve allowing air
inlet duct to flow into the intake manifold.
RESULTS OF INCORRECT OPERATION
@ If no air (oxygen) flow enters the exhaust stream
at the exhaust ports, HC and
CO emission levels
will be too high.
@ Air flowing to the exhaust ports at all times could
cause
a rich ECM command and increased
temperature of the converter. This may also cause
a Code
44 due to oxygen being pumped passed the
oxygen sensor. There should be no air going to the
exhaust ports while operating in the closed loop
mode.
DIAGNOSIS
The diagnosis of the AIR system is covered in
CHART C-6 at the end of this section.
OPERATIONAL CHECKS
A.I.R. Pump
1. The air pump is a positive displacement vane type
which is permanently lubricated and requires no
periodic maintenance.
Accelerate engine to approximately
1500 rpm's
and observe air flow from
hose(s). If air flow increases
as engine is accelerated, pump is operating
satisfactorily. If air flow does not increase or is not
present, proceed as follows:
Inspect
For proper drive belt tension.
2. For a leaky pressure relief valve. Air may he
heard leaking with the pump running.
DECELERATION VALVE
1 VACUUM BLEED VALVE
1 MANIFOLD VACUUM
1 DECELERATION AIR TO INTAKE
MANIFOLD
1 FILTERED AIR FROM INTAKE DUCT
/ DIAPHRAGM
05 10 84 5s 1726-6E
Figure C6-2 - Deceleration Valve
NOTICE: If the engine or underhood compartment
is to he cleaned with
steam or high-
pressure detergent, the centrifugal filter
fan should be masked "OFF7' to prevent
liquids from entering the pump.
Inspect
3. For a seized Air Injection Pump.
3. Hoses, tubes and all connections for leaks and
proper routing.
5, For air flow from controllswitching valve.
6. AIR injection pump for proper mounting and bolt
torque.
7. If no irregularities exist and the AIR injection
pump noise is still excessive, remove and replace
pump.
CAUTION: Do Not Oil Air Pump
Hoses and Pipes
Inspect
1. Hose or pipe for deterioration or holes.
2. All hoses or pipe connections, and clamp tightness.
3. Hose or pipe routing. Interference may cause
wear

DRIVEABILITY AND EMISSIONS 2.8L (WIN 5) 6E3-C6-3
4. If a leak is suspected on the pressure side of the
system or if
a hose or pipe has been disconnected
on the pressure side, the connections should be
checked for leaks with a soapy water solution.
With the pump running, bubbles will form if
a
leak exists.
Deceleration Valve
1. Connect tachometer, start engine and allow idle to
stabilize.
2. With the engine running at specified idle speed,
remove the small deceleration valve signal hose
from the manifold vacuum source.
3. Reconnect the signal hose and listen for air flow
through the ventilation pipe and into the
deceleration valve. There should also be a
noticeable speed drop when the signal hose is
reconnected.
4. If the air flow does not continue for at least one
second or the engine speed does not drop
noticeably, check the deceleration valve hoses for
restrictions or leaks.
5. If no restrictions or leaks are found, replace the
deceleration valve.
Check Valve
Inspect
1. A check valve should be inspected whenever the
hose is disconnected form
a check valve or
whenever check valve failure is suspected.
(A
pump that had become inoperative and had shown
indications of having exhaust gases in the pump
would indicate check valve failure).
2. Blow through the check valve (toward the exhaust
manifold) then attempt to suck back through the
check valve. Flow should only be in one
direction(towax-d the exhaust manifold). Replace
valve which does not operate properly.
ON-CAR SERVICE
DRIVE BELT
Remove or Disconnect
1. Inspect drive belt for ware, cracks or deterioration
and replace if required. When installing new belt,
it must be seated and fully secured in grooves of
A/C compressor, AIR pump, generator, and
crankshaft pulleys.
A.I.R. PUMP
Remove or Disconnect
1. Hold pump pulley from turning by compressing
drive belt, then loosen pump pulley bolts.
2. Loosen bolt, holding pump to mounting brackets,
release tension on drive belts.
3. Move belts out of the way, then remove pump
hoses, vacuum and electrical connections, and
control valve.
4. Pulley, then pump.
5. If required, insert needle nose pliers and pull filter
fan from hub.
Install or Connect
1. Air pump assembly, and tighten mounting bolts.
2. I-loses, vacuum and electrical connections, and
control valve
3. New
filter
fan on pump hub.
4. Spacer and pump pulley against centrifugal filter
fan.
5. Pump pulley bolts and tighten equally to 13 N m
(10 lb.
ft.). This will compress the centrifugal
filter fan onto the pump hole. Do not drive filter
fan on with a hammer. A slight amount of
interference with the housing bore is normal.
After a new filter fan has been installed, it
ma?;
squeal upon initial operation or until 0.11, sealing
lip has worn in. This
may require a short period of
purnp operation at various engine speeds.
6. Pump drive belt and adjust.
a Lon 7. Check air injection system for proper oper t'
(see CHART C-6)
AIR CONTROL VALVE
Remove or Disconnect
1. Battery ground cable.
2. Adapter bolts (See Figure C6-3).
3. Air outlet hoses from valve.
4. Adapter.
5. Electrical connectors and vacuum hoses from
valve. ve.
6. Control
va 1
Install or Connect
1. Control valve.
2. Electrical connectors and vacuum hoses.
3. Adapter.
4. Air hoses to valve.
5. Adapter bolts to pump.
6 Batterv ground crtble.
7. Check system operation (see CHART C-6)

6E3-C6-4 2.8L (WIN S) DRIVEABILITY AND EMlSDlONS
A.I.R. PUMP ASM
PULLEY
SPACER
PULLEY BOLT 27 N
rn (20 FT. LBS.)
BRACKETS (UPPER AND LOWER)
[ BOLTS (2) 80 Nm (60 FT. LBS.)
NUTS (2) 50 N.rn (36 FT. LBS.)
( UPPER PUMP BOLT 35 N,rn (26 FT. LBS.)
( LOWER PUMP BOLT 35 N.rn (26 FT. LBS.) 7s 3317-6E
Figure C6-3 -Air Pump Mounting
CONTROL VALVE
( DIVERT SILENCER
1 A.I.R. PUMP ASM
CHECK VALVE
Remove or Disconnect
1. Any parts required for access.
2. Release clamp and disconnect air hoses from check
valve.
3. Unscrew check valve from air injection pipe.
install or Connect
1. Screw check valve onto air injection pipe.
2. Position air hoses on check valve and secure with
clamp.
3. Any parts removed for access.
DECELERATION VALVE
Remove or Disconnect
1. Vacuum hoses from valve.
2. Screws securing valve to engine bracket.
3. Deceleration valve.
Figure C6-5 - Control Valve Service
Install or Connect
1. Deceleration valve.
2. Screws securing valve to engine bracket.
3. Vacuum hoses to valve.
1 BOLT (2) 16 N.rn (12 FT. LBS.)
1 NUTS (2) 24 N.rn (18 FT. LBS.) 7s 3315-6E
Figure C6-4 - Control Valve Service

DRIVEABILITY AND EMISSIONS 2.8L (VIN 0) 6E3-C6-5
PART NAME CROUP
Bracket. AIR Inj Pump Supt (RR) .........
Bracket. AIR Inj Pump (Frt) .............
Bracket. Dclr Vlv ....................
Gasket. AIR Cont Vlv ..................
IIose. AIR 111j Cont Vlv .................
........ Ilose. Clcase Vent Pipe to Dclr Vlv
Pipe . AIR 1n.j Ctltc Conv Chk Vlv .........
Pipe . AIR Inj Cont Vlv .................
Pulley. AIR tnj Pump .................
Punlp. AIR Ini .......................
Silencer. AIR Inj Corit Vlv ..............
Valve. AIR Inj Cont ...................
Valve. AIR I11j Eng Ckik ................
Valve. Ilclr ..........................

6E3-C6-6 2.8L (VIN S) DRlVEABlLlTY AND EMISSIONS
AIR SOLENOID
CHART C-6
ELECTRIC CONTROL (DIVERT)
(MANUAL TRANSMISSION)
2.8L (VIN S) "'F" SERIES (PORT)
Circuit Description:
This system uses a single bed converter and Air Management is controlled by an Air Control Valve (divert
valve).
When grounded by the ECM, the solenoid causes the valve to direct air to the exhaust ports. When
dc-
energized air diverts to the atmosphere, air will go to the ports provided the valve has a ground to the ECM and
good manifold vacuum.
Test Description: Numbers below refer to circled 3. Checks for an open control circuit. Grounding test
numbers on the diagnostic chart. terminal will energize the solenoid if ECM and
1. This is a system performance test. When vehicle circuits are normal. In this step, if test light is
goes to closed loop, air will switch from the ports to "ON", circuits are normal and faulty is in valve
divert. connections or valve.
2. 'rests for a grounded electric divert circuit.
Normal system light will be
"OFF".

DRIVEABILITY AND EMISSIONS 2.8L (VIM 5) 6E3-C6-7
LE (UNDER 2000 RPM).
PORTS UNTIL SYSTEM GOES