Vacuum Leak When Fan running

NCoppersmith

Member
:
Mazdaspeed Protege 3.5
Hey all, discovered a weird vacuum issue the other day and wondered what it could be. If the fan control is turned off, I pull ~20hg of vacuum, sometimes a little less. But if I turn the blower fan on (no AC, just vent) I drop to about 14-16 and the engine starts idling ragged. Turn the fan off, and the idle smooths out and the vacuum goes back to normal.

Anyone run into this before? Seems odd that a fan would cause the vacuum to go haywire.
 
It's probably something electrical causing the idle to drop and the vacuum is just a symptom. Check that your battery connections are tight and maybe check the alternator to ensure it's putting out ~14volts. Could even be a weak or loose ground
 
Back