twoeightyzx Posted May 23, 2007 Share Posted May 23, 2007 I've searched and haven't found any help up to this point. When I first bought my '79 280zx she idled steady but high and smoking when i had to brake quickly. Did some searching and found craked hoses leading to a/c and cruise control. After replacing them, I lowered the Idle Air Control (after driving to normal operating temp) back to the factory 750rpm. Idle became smoother yet smoking still existed. More searching lead me to the possiblity of a bad PCV valve. Since the current one looked original I swapped it for a new one along with a new hose and a new hose on the valve cover. It doesn't smoke all the time only when I have to brake suddenly. This morning I had to stop quickly while traveling 10mph, rpms dropped to 500 but raised back up and she smoked for 15 seconds and cleared up. I have yet to find more vacume leaks and she isn't using any oil. If I can I'll try to get a picture of the smoke. Any advice, questions, or commets are appeciated. Quote Link to comment Share on other sites More sharing options...
Pete84 Posted May 23, 2007 Share Posted May 23, 2007 What color is the smoke? Quote Link to comment Share on other sites More sharing options...
twoeightyzx Posted May 23, 2007 Author Share Posted May 23, 2007 Sorry, the smoke is white and dense. Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted May 23, 2007 Share Posted May 23, 2007 Not oil then; maybe brake fluid from bad master and booster? <> Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 23, 2007 Share Posted May 23, 2007 The drop in idle when braking could be a vacuum leak in the brake booster. Hook a vac pump and guage to it and do a leak down test. Quote Link to comment Share on other sites More sharing options...
twoeightyzx Posted May 24, 2007 Author Share Posted May 24, 2007 Thanks for the help guys. It has been using small amounts of brake fluid but I just thought it was a leak at one of the calipers. I think I'm going to change out the booster and master cylinder. If its not totally because of them atleast they will be new. Quote Link to comment Share on other sites More sharing options...
naviathan Posted May 24, 2007 Share Posted May 24, 2007 Yeah, my bet would be on a leaking master cylinder into booster and booster leaking into vacuum assist during braking. Quote Link to comment Share on other sites More sharing options...
Ledphoot Posted May 24, 2007 Share Posted May 24, 2007 agreed Quote Link to comment Share on other sites More sharing options...
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