Distributor Vacuum Control: Testing and Inspection

NOTE: Air cleaner inlet air temperature must be below 40 F. If engine is warm, cool the TVS in the air cleaner to below 40 F.


1. Start engine, then check for manifold vacuum at vacuum hose at reverse delay valve. If there is no vacuum, replace TVS.
2. Disconnect each delay valve and check for vacuum. Replace each valve as necessary.