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Vacuum Delay Valve

  1. Remove vacuum delay valve from vehicle. Connect vacuum gauge to carburetor side of valve (flat side of valve). Connect distributor side (tapered side) to intake manifold vacuum source.
  2. Start and run engine at idle. Note vacuum reading on gauge. Pull intake manifold vacuum source hose off and record time it takes vacuum to change from idle vacuum level to 12 in. Hg. It should be within specifications shown in DELAY VALVE SPECIFICATIONS table. If not, replace spark delay valve. Ensure that arrow on delay valve is installed toward distributor.
DELAY VALVE SPECIFICATIONS

Application Seconds
B2000 4-6
GLC Federal (Wagon) 4-10
  Calif. Sedan 4-10
  Wagon 10-20
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