HLChoppers Posted February 9, 2007 Share Posted February 9, 2007 I finally found a 280ZX for a good price that was not rusted out, in fact no rust at all. I have had a few 280s before but this one is confusing me. It is a none turbo with auto trans (will be completeing a 5 speed swap soon). It is running very rough. It seams like it has a vaccum leak or miss. I have checked and there is no miss, all cyclinders are firing right. I have replaced all cracked vaccum lines already. When it is running and I press on the brake the idle speeds up and then slows down. Please let me know if you have any idea what is going on. Also when I replced the fuel lines there was gas flowing out of the return line coming from the gas tank (constant). Thanks Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted February 9, 2007 Share Posted February 9, 2007 Sounds like your break booster diaphram is leaking.. Try capping off the break booster vacume and go for a drive. (Just remember , you have no power assist breaks.) Quote Link to comment Share on other sites More sharing options...
HLChoppers Posted February 9, 2007 Author Share Posted February 9, 2007 tried it. Did not make a difference other than the idle does not change any more. Also this car was sitting for about 6 years from what I was told. Also I checked the timing and its fine. It does have an exhaust leak on the down tube. Quote Link to comment Share on other sites More sharing options...
atx_s130 Posted February 9, 2007 Share Posted February 9, 2007 fuel presure regulator. dead injector could be a lot of things Quote Link to comment Share on other sites More sharing options...
AK-Z Posted February 12, 2007 Share Posted February 12, 2007 Is it an different on the higher band of the RPMs? if it runs better then it could be the connection to the TPS. Just clean the connections. Quote Link to comment Share on other sites More sharing options...
82Beach Turbo Posted February 15, 2007 Share Posted February 15, 2007 Emissions System........02 sensor, CO2 Quote Link to comment Share on other sites More sharing options...
HLChoppers Posted February 15, 2007 Author Share Posted February 15, 2007 I have tried a few more things. Still running very rough. I found out that the engine runs smother with any vaccum line off. I am thinking that the AFM is not working right. Is there any check I can do to see if the afm is missed up? could a faulty Fuel regulator cause this problem too? Quote Link to comment Share on other sites More sharing options...
datsunlover Posted February 16, 2007 Share Posted February 16, 2007 I will bet the AFM boot is cracked (the one between the AFM and throttle body) and sucking extra air into the intake. The AFM will not 'see' this extra air, but it's there... causing a lean condition. The 02 might pick this up and tell it to crank up the injectors, which will make it rich...but wait now... that's too much fuel... so it backs off... and so on and so forth. (this will happen very quickly in the ECU, ussualy giving a rough idle/poor drivability) There are voltage/resistance checks you can do on the AFM, basic checks really.. but any manual (factory, maybe the Haynes booz) will give you the proper 'range' of readings to look for. Quote Link to comment Share on other sites More sharing options...
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