Crazy vacuum leak!
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
Crazy vacuum leak!
So I am chasing why my 82 is idling so high. Aboutg 1100 rpm. Under load, is still in 900. Thinking maybe timing is off. It isn't. Thinking stuck in open mode - bad thermostat or something. But I have a low-temp chip that will handle the 180* thermo, so that can't be it. Then Friday, coming home from work, put on the vent - its been cool enough in Houston lately that no need for a/c or vent. Just crack the passenger window. But, no air coming through dash vent, just floor. Then I remembered the tiny vacuum hose that runs behind the distributor trough the firewall to the controls that control the air distribution flap inside. Sure enough, that small hose had become brittle after 29 years and 212K miles and had broken off from the firewall connector. Replaced it with some new, flexible tubing and all is well. Air distribution flap works fine, rpm dropped to about 750+. Amazing what a small leak can do. ID of hose must be 1/16" but that is enough. Also enough to just let the slightest engine smell work its way into the cockpit through the firewall connector. Could have searched for the problem for a long time.
