Throttle Positioner (Modulator) Diaphragm Check
- Disconnect vacuum line from diaphragm. Connect a vacuum pump to diaphragm. Apply 19 in. Hg vacuum.
- If diaphragm does not respond, or will not hold vacuum, replace diaphragm. If diaphragm responds and holds vacuum, proceed with testing.
- Remove vacuum pump from diaphragm. If diaphragm does not return within 5 seconds, replace defective diaphragm. Reconnect vacuum line. If diaphragm returns in 5 seconds, diaphragm is good.