Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1988STEP VAN P20, 7.4 W, AUTOMATIC, 475/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEEMISSIONSSTATE EMISSION STANDARDS - GASOREGON
1988 Chevrolet Step Van P20, 7.4 W, Automatic, 475/M40
State Emission Standards - Gas: OREGON
1988 Chevrolet Step Van P20, 7.4 W, Automatic, 475/M40SECTION OREGON
OREGON EMISSION STANDARDS - METROPOLITAN PORTLAND ENHANCED AREA - BAR31
| Application | HC gpm (CO gpm) | NOx gpm | |
|---|---|---|---|
| Light Duty Passenger Cars | |||
| 1981-82 | 2.0 (64) | 3.70 | |
| 1983-89 | 2.0 (32) | 3.70 | |
| 1990-95 | 1.2 (30) | 3.00 | |
| 1996 & Newer | OBD-II Test | OBD-II Test | |
| Light Duty Trucks (6000 GVWR Or Less) | |||
| 1981-83 | 8.5 (149) | 8.32 | |
| 1984-87 | 4.0 (85) | 8.32 | |
| 1988-89 | 4.0 (85) | 4.62 | |
| 1990-95 | 2.4 (80) | 3.75 | |
| 1996 & Newer | OBD-II Test | OBD-II Test | |
| Light Duty Trucks (6001-8500 GVWR) | |||
| 1981-83 | 8.5 (149) | 8.32 | |
| 1984-87 | 4.0 (85) | 8.32 | |
| 1988-89 | 4.0 (85) | 6.47 | |
| 1990-95 | 2.4 (80) | 5.25 | |
| 1996 & Newer | OBD-II Test | OBD-II Test | |
OREGON EMISSION STANDARDS - METROPOLITAN PORTLAND & ROGUE VALLEY AREA BASIC TEST - 2-SPEED IDLE TEST
| Application | Idle HC ppm (CO %) | 2500 RPM HC ppm (CO %) | |
|---|---|---|---|
| Light Duty Passenger Cars (6000 GVWR Or Less) | |||
| 1975-80 (No Catalyst) | 300 (2.5) | - | |
| 1975-80 (Catalyst) | 220 (1.0) | - | |
| 1981 & Newer (All) | 220 (1.0) | 220 (1.0) | |
| 1975 & Newer (2-Stroke) | n/a (7.0) | - | |
| Light Duty Trucks (6001-8500 GVWR) | |||
| 1975-78 (All) | 350 (2.5) | - | |
| 1979-80 (No Catalyst) | 300 (2.5) | - | |
| 1979-80 (Catalyst) | 220 (1.0) | - | |
| 1981 & Newer (All) | 220 (1.0) | 220 (1.0) | |
| 1996 & Newer (3750 LVW Or Less) | 0.9 (20) | 2.25 | |
| Heavy Duty Trucks (8501 GVWR Or More) | |||
| 1975-78 (Carbureted) | 500 (4.0) | n/a (3.0) | |
| 1975-78 (Fuel Injection) | 500 (4.0) | - | |
| 1979-84 (Carbureted) | 350 (3.0) | n/a (3.0) | |
| 1979-84 (Fuel Injection) | 350 (3.0) | - | |
| 1985 & Newer (No Catalyst) | 350 (3.0) | n/a (3.0) | |
| 1985 & Newer (W/Catalyst) | 220 (1.0) | 220 (1.0) | |
OREGON EMISSION STANDARDS - METROPOLITAN PORTLAND & ROGUE VALLEY AREA BASIC TEST - EXHAUST OPACITY TEST
| Application | Opacity % @ Idle | Opacity % @ High Idle | |
|---|---|---|---|
| 1975 & Newer | |||
| 2-Cycle Engines | 20 | ..... | |
| Gasoline Engines | 0 | 0 | |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.