Mycarispurty Posted January 6, 2008 Share Posted January 6, 2008 Ok so I got this 280Z the other day, and it idles at about 1500 RPM and chugs some black smoke out of the tail pipe and a quick puff on revving it. I know the AFM is probably the main suspect here, another big clue is the electrical cover is removed. Well I did my best to clean the carbon trace, the contacts and measure ohm markings according to Blue's tech tips, and none of the numbers really reached what his page said they should. Well I figure maybe a bad cold start valve or air regulator could be helping the problem. So I figured I'd just unplug the connector to the cold start valve and fire it up. Still idled high and puffed out black smoke, so I unplugged the air regulator. Both times, nothing changed. Well I figured I'd monkey with the wiper arm on the AFM and as I opened the flap more, the idle went way down. Of course I'm not omni present so I couldn't jump in the cab to see what the tach was saying but I did hear the engine rev much slower. The further I swept it the lower the idle went to where it almost bogged out and stalled a couple times. After a few sweeps, I figure that is the main culprit in at least the high idle and the air regulator probably has nothing to do with it. I've been reading the EFI Bible religiously (no pun intended) trying to get some clues as to what to check. I'm definitely getting an AFM from a guy on here who has a tester and says they test w/i spec so that should get that covered. Anyone have some insite? I suppose I'm on the right track, and worst case scenario is I throw enough money at it and replace all the EFI sensors (AFM, cold start valve, head temp sensor, thermotime, water temp, etc) and then replace all the vacuum lines then it should work like new, considering all the parts are new. Quote Link to comment Share on other sites More sharing options...
Accurate Injection Posted January 6, 2008 Share Posted January 6, 2008 timing been Changed? Kevin Quote Link to comment Share on other sites More sharing options...
Mycarispurty Posted January 6, 2008 Author Share Posted January 6, 2008 Not that I know of, but I can check it. Also the previous owner said the problem seems to get worse when the engine warms up. Don't know if he meant rich mixture or idle though. Quote Link to comment Share on other sites More sharing options...
Accurate Injection Posted January 7, 2008 Share Posted January 7, 2008 Check your Base Timing to be sure! Kevin Quote Link to comment Share on other sites More sharing options...
Thumper Posted January 7, 2008 Share Posted January 7, 2008 Intake leak also will cause this. Check torn boots and gaskets. Quote Link to comment Share on other sites More sharing options...
Mycarispurty Posted January 7, 2008 Author Share Posted January 7, 2008 I was going to replace all the hoses and gaskets that I could easily get to. I have noticed that on the very back of the intake manifold, the EGR valve is gone. The holes in the mount are exposed but upon glancing, I don't recall seeing any air ways leading into the manifold that could cause a leak but I'll check again. Quote Link to comment Share on other sites More sharing options...
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