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.