What emission components are required for a 1976 Jeep with a 4.2L engine?

• A. Pcv, Tac, Evp, Egr
• B. Pcv, Tac, Evp, Egr, Spk
• C. Pcv, Tac, Evp
• D. Pcv, Egr, Spk, Evp

Answer: (B)

In older, CA-spec smog systems, several emission-control devices work together to keep exhaust emissions in check: crankcase vapors are recycled back into the intake, fuel vapors are captured and later purged, exhaust gases are recirculated to lower combustion temperatures, and ignition timing is managed to ensure clean, complete combustion. The set shown includes all of these functions: the PCV valve handles crankcase ventilation; the TAC device modulates air during idle/warm-up to control idle emissions; the EVP is the evaporative purge valve that works with the EVAP canister to purge fuel vapors into the engine; the EGR valve reduces NOx by recirculating a portion of exhaust back into the intake; and the SPK component covers the ignition/spark timing needed for proper combustion. This combination reflects the complete emission-control package that a 1976 4.2L Jeep would typically require. Other options omit one or more of these essential parts, making them incomplete.