AceOfDiamonds0 Posted August 31, 2013 Report Share Posted August 31, 2013 I have an issue that has either recently developed or just gotten notably worse. I've got a 71 240Z with the triple 40 dcoe's on an L28 and and EI dizzy. I've had a few minor tuning and synchronizing issues but nothing serious. A few days ago I noticed that when I'm stopped and press the brakes my idle goes up 100 to 300 rpm's. I've suspected there might be a vacuum leak for sometime but nothing this noticable. I've already replaced the inline check valve after the brake booster. I've also taken a can of starting fluid and sprayed the lines on the brake booster, all around the intake manifold and anywhere else I could think of to check for vacuum leaks a few times and still nothing and it is quite frustrating! Now that the idle goes up when i press the brake I've noticed a substantial decrease in mileage so I need to resolve this issue as soon as i can because gas is not cheap and I'm not rich lol. Quote Link to comment
thisismatt Posted August 31, 2013 Report Share Posted August 31, 2013 Did you rule out the internal diaphragm of the booster? Quote Link to comment
AceOfDiamonds0 Posted August 31, 2013 Author Report Share Posted August 31, 2013 No I didnt. I dont know a whole lot about it or how it works other than using vacuum from the intake manifold to assist the the effort of applying pressure to the brakes. How could I test it to find out if its bad? Quote Link to comment
thisismatt Posted August 31, 2013 Report Share Posted August 31, 2013 Check out this pdf, it has a good explanation of how they work and some diagnostics http://www.autoshop101.com/forms/brake05.pdf Quote Link to comment
AceOfDiamonds0 Posted September 4, 2013 Author Report Share Posted September 4, 2013 Ok I'm going to say its the booster then. I'll pull it off and see if I can find anything. Quote Link to comment
AceOfDiamonds0 Posted September 12, 2013 Author Report Share Posted September 12, 2013 Ok so I was losing vacuum through the diaphragm on the brake booster. I pressed the brake with it running and heard it sucking air. Replacing it tomorrow morning to confirm the fix. Quote Link to comment
thisismatt Posted September 13, 2013 Report Share Posted September 13, 2013 Fix it? Quote Link to comment
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