| You are correct. The regulation of vacuum is done by the white vacuum valve mounted at the rear of the inj. pump. Monitor it there. Should be steady hi vacuum there then as the throttle is depressed, should slowly drop to half the vacuum reading at half throttle. Log onto dieselgiant.com for a better description. Readjust the modulator back to its prior setting, they dont go out of adjustment as a rule. Sometimes the o ring inside the modulator plastic cover can fail and cause a vacuum leak but you are not describing that symtom. Sounds to me like the switch over valves on the top of the valve cover are leaking. |