Jaguar Workshop Service and Repair Manuals

Distributor Vacuum Control: Testing and Inspection
Dump Valve

Vacuum Hose Routing

1.

Disconnect two vacuum hoses from dump valve.

2.

Connect a hand-held vacuum pump with gauge to each  vacuum port.

3.

Apply vacuum to the upper port, approximately 18 in Hg.

4.

Apply vacuum to lower port, approximately 11 in Hg.

5.

Both ports should hold vacuum.

6.

With vacuum holding on both ports, release vacuum to upper port.  Lower port vacuum should vent when this is done.

7.

If tests are not satisfactory, replace vacuum regulator.