Vacuum Delay Valve
- Remove vacuum delay valve. Connect distributor side of valve to intake manifold vacuum source. Connect vacuum gauge to opposite side of valve.
- Start engine and idle. Note idle vacuum level. Pull intake manifold vacuum source off and record time it takes vacuum to decrease 11.8 in. (300 mm) Hg from idle vacuum reading. Time period should be within specifications shown in chart. If not, replace spark delay valve.
Delay Valve Test Times
| Application | Seconds | |
|---|---|---|
| GLC | ||
| Calif. Auto. Trans. | 4-10 | |
| All Others | 10-20 | |
| B2000 | 4-6 | |