Emission System Quick Reference
Footnote(s):
X - Equipped
- Not Equipped
1 - Except 1.6L, HEI/EST. 1.6L, HEI.
2 - Type, TWC; number of catalytic converters, 1.
3 - One O2S.
4 - 4 spd. shown, 5 spd. equipped models adjust timing to 8 degrees BTDC at 950 RPM.
5 - Diesel engine.
6 - Static timing.
7 - FWD models.
8 - RWD models.
9 - Dynamic injection timing using timing meter.
10 - Eighth digit of Vehicle Identification Number (VIN) denotes engine code.
11 - VIN H, Chevrolet engine.
12 - VIN S & 7, Chevrolet engines.
13 - VIN Y, Oldsmobile engine.
14 - VIN 9, Oldsmobile engine.
15 - VIN 6, Oldsmobile engine.
16 - Disconnect & plug distributor vacuum advance hose.
17 - Models w/4 spd. transmissions, disconnect & plug distributor vacuum advance hose; models w/5 spd. transmissions, disconnect 4 wire EST connector at distributor.
18 - Disconnect 4 wire EST connector at distributor.
19 - Ground test terminal in connector under dash
20 - Disconnect green reference signal connector located rear of engine near distributor.
21 - Disconnect set timing bypass connector (tan/black wire). May be located at: 1, RH valve cover, 2, near blower motor, 3, near distributor, 4, taped to engine harness near left strut tower.
22 - Open set timing connector.
23 - Back-pressure EGR.
24 - AIR (Secondary Air Injection) pump type.
25 - ECM controlled EGR.
26 - Pulse width modulated EGR.
27 - Diesel engine EGR.
28 - PAIR (Pulse Air Injection).
29 - Type, TWC or TWC+OC number of catalytic converters, 1.
30 - Type, TWC+OC; number of catalytic converters, 1.
31 - On Firebird models when replacing canister control valve, refer to Technical Service Bulletins.
32 - DI/HEI/EST/ESC.
33 - DI/HEI.
34 - On certain Cavalier models, the PAIR check valve may require replacement.
35 - Certain Cadillac models may experience a restricted catalytic converter.
36 - Certain California Cimarron models may EGR valve vacuum signal problem.
37 - On certain LeSabre & Regal models, may experience AIR tube corrosion.
38 - On certain Calais, Cutlass & Cutlass Supreme models, may experience AIR tube corrosion.
39 - C-3 System.
40 - Tel System.
41 - Certain Toronado models may emit pollutants in excess of emission standards due to restricted catalytic converter.
42 - Certain Buick models may emit pollutants in excess of emission standards due to restricted catalytic converter.
43 - Certain Buick & Oldsmobile models may emit pollutants in excess of emission standards due to plugged EGR vacuum hoses.