Guest jjohart Posted January 21, 2005 Share Posted January 21, 2005 I have the 280ZX 83 service manual, and it shows a screwdriver turning a bolt or something to raise or lower idle...my mechanic and I can't find that area/part anywhere! Can anyone tell me where to look better than that manual's drawings (all too often, they show some poor Japanese/English mechanic guy like Spritle from Speed Racer sucking in dangerous fluids to check vacuum levels!!)--bonus points if you can provide a photo/JPEG! Thanks John-83 280ZXT, I/C, and idles to stall point all too often! Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted January 22, 2005 Share Posted January 22, 2005 I don't know if this helps but I took a picture of the air flow in the intake manifold from my 1980 280ZX FSM and it shows the idle adj. screw placement on the intake manifold. LARRY Quote Link to comment Share on other sites More sharing options...
datsunlover Posted January 22, 2005 Share Posted January 22, 2005 IIRC, that screw is in there really tight too.. (some sort of thread lock from the factory) I don't think that it was intended to be used to adjust periodicaly, but it was more for final tuning after assembly at the factory. I tried adjusting one of my 280zx's and didn't have any luck with it.. Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted January 22, 2005 Share Posted January 22, 2005 Well........ Item 4 in my above post is the throttle chamber which is located between the air flow meter and the intake manifold and it is equipped with a valve. This valve controls the intake air flow in response to accelerator pedal movement. This valve remains closed during engine idling and the air required for idling passes through the by-pass port into the intake manifold. Idle adjustment is made by the idle adjusting screw located in the by-pass port on the throttle chamber. LARRY Quote Link to comment Share on other sites More sharing options...
Warren Posted January 22, 2005 Share Posted January 22, 2005 WHOA, hang on a second. It could just be me on this one, but if it is a ZXT, and it's still "stock" then the following text from the FSM should apply. This is the first thing they say about the ECCS system controlling the idle on the ZXT (different from the EFI system controlling idle on the ZX). The ECCS System is covered in the FSM, AFTER the EFI system. "OUTLINE In the Electronic Concentrated Engine Control System (E.C.C.S.), the control unit employs a micro-computer. This micro-computer controls fuel injection, spark timing, exhaust gas recirculation (E.G.R.), idle speed, fuel pump operation and mixture ratio feedback. It is unnecessary to adjust idle CO%, idle rpm and ignition timing. Electrical signals from each sensor are fed into the micro-computer and each actuator is controlled by an electrical pulse with a duration that is computed in the micro-computer." Perhaps this explains why he cannot find the idle speed adjustment screw on the throttle body. While this information comes from the 1982 model FSM, the 1983 "should" be similar if not exactly the same. Refer to the EFEC section in the FSM for more information FWIW, when my car started doing what yours is doing, idling too low and stalling (if I read it right), I found that the little vacuum lines on the VCM (Vacuum Control Modulator) near the AFM had split and were leaking. I replaced those 3 vacuum lines and the problem instantly disappeared. Hope this helps a little. Quote Link to comment Share on other sites More sharing options...
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