Ghettodeffender Posted February 15, 2012 Share Posted February 15, 2012 (edited) so my car began doing all the symptoms of a bad airflow meter, so i took it to a shop for diagnosis. they confirmed my suspicion that it was a bad airflow meter and a clogged egr system. I replaced the air flow meter, and unclogged the EGR system and replaced the EGR valve, however the problem still persists. the car idles poorly and misfires under acceleration. it sounds like its not running on all cylinders. All the injectors were tested to be working, and when i try to adjust the idle using the idle screw it doesn't seem to respond much to it. Also if i take the oil cap off when the car is running it doesn't run any different (i Believe the engine is supposed to die if you do that). So Hybrid Z community, what are your thoughts on the cause of this problem, i dont want to keep throwing money at parts that arent causing the problem. Car is a 1977 280z Edited February 15, 2012 by Ghettodeffender Quote Link to comment Share on other sites More sharing options...
galderdi Posted February 15, 2012 Share Posted February 15, 2012 Are you sure you are adjust the idle screw and not the mixture screw? Quote Link to comment Share on other sites More sharing options...
Ghettodeffender Posted February 15, 2012 Author Share Posted February 15, 2012 (edited) I'm adjusting the screw circled in attatched picture Edited February 15, 2012 by Ghettodeffender Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 15, 2012 Share Posted February 15, 2012 Those are all symptoms of an intake system vacuum leak. Check your hoses. There have been cases of the EGR system corroding through, giving full-time EGR, which would be an internal vacuum leak. If you can't find a leak anywhere else. Quote Link to comment Share on other sites More sharing options...
ttodhunter Posted February 15, 2012 Share Posted February 15, 2012 It kinda sounds like you have a large vacuum leak or the timing is way off. For vacuum, check the intake boot for cracks in the accordian section, check all the small lines running around the engine, all the hoses for pcv. Borrow a vacuum tester from O'Reilly's or wherever then follow the instructions on this page: http://www.atlanticz.ca/zclub/techtips/vacuum/index.html Do a check of the timing. '76 manual shows idle timing of 10* BTDC (engine cold) or 7* (engine warm). Hope that helps, if not, those are still good things to do and they're free. Quote Link to comment Share on other sites More sharing options...
neotech84 Posted February 15, 2012 Share Posted February 15, 2012 No it won't die if you remove the oil cap. How is your timing? Fuel pressure? Filters? Ect. We need a little more info than you have given. Quote Link to comment Share on other sites More sharing options...
Ghettodeffender Posted February 16, 2012 Author Share Posted February 16, 2012 No it won't die if you remove the oil cap. How is your timing? Fuel pressure? Filters? Ect. We need a little more info than you have given. Fuel Filter apears to be new, fuel pump is new, fuel pressure set to 36 psi, not sure on the timing, however the car was only sitting in my drve way and i would start it up and let it idle every day, i havent been driving it since the clutch went out. it was idling fine until i removed the valve cover to clean and replace the original gasket, i used a new gasket and sealent on the valve cover and put it back on the engine, i then started her up about an hour later and she starting running like ****, as i described. so i am going to remove the valve cover, put on the gasket this time without sealent and tighten it up nicley to see if that gets rid of the vaccume leak. that is the only thing i can thing it might be (most of the time something like this happens, it seems to be part of a human error). ill let you guys know if that was the source of the vaccume leak Quote Link to comment Share on other sites More sharing options...
neotech84 Posted February 16, 2012 Share Posted February 16, 2012 K. Sounds good. Hope you find the problem. Quote Link to comment Share on other sites More sharing options...
Ghettodeffender Posted February 16, 2012 Author Share Posted February 16, 2012 K. Sounds good. Hope you find the problem. So just an update, i replaced the vlave cover gasket, this time i sanded the **** out of any place that could potentially cause a vaccum leak, so when i put the gasket back on everything was smooth, i then beaded oil on the gasket and put the valve cover back on, fired her up and still runnin like ****, i tested it with a vaccume tester again, and it was at 13 psi at idle like it had been before i changed it. so i took it to a local shop to have them diagnose the vaccume leak source. Quote Link to comment Share on other sites More sharing options...
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