Guest 79 280zx Posted March 16, 2004 Share Posted March 16, 2004 Hi, I have a '79 280zx. Problem is I have been having a rough idle. I noticed that I have a fairly decent idle until I turn on the lights, then the rpms drop, it stalls when I start the heater, I've changed the alternator and the battery, what gives? Problem: Last owner put in a cam. I have done leak searches till I can't stand the smell of carb cleaner and have replaced injector gaskets. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted March 17, 2004 Share Posted March 17, 2004 Well the heater controls are vaccum operated so maybe you dont have enough vaccum for some other things....fuel pressure regulator? I cant remeber if the fuel pressure regulator is vaccum controlled or not? As for when you turn on the lights the idle drops a little...how much is a little? Have you taken a vaccum reading at idle? Should be somewhere around 20psi Also do you have the specs on the cam? Guy Quote Link to comment Share on other sites More sharing options...
Guest 79 280zx Posted March 20, 2004 Share Posted March 20, 2004 Hey Guy, I really feel that my problem is a short, somethings going to ground 'cause I'm gotta' be losing AMPS somewhere. Gonna' sand blast the engine compartment and POR 50 it. No idea what the cam specs are, Just got a engine hoist, you know the story, now I'm standing at the crossroads, Supposedly the entire engine/tranny is rebuilt with only a few thousand miles on it. .....But I look at your LT... Quote Link to comment Share on other sites More sharing options...
j260z Posted March 20, 2004 Share Posted March 20, 2004 definately sounds like a charging system problem. your lights take up enough juice that your system cannot fire the spark plugs. check the voltage regulator. i'm not sure whether the zx's had internal or external regulators. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted March 23, 2004 Share Posted March 23, 2004 Well if you think its a short to ground, start unplugging things and see if the problem goes away. Once you find something that, when unplugged the problem is gone, you have found the circuit to look more in depth to. The ZX's had internal regulators. Guy Quote Link to comment Share on other sites More sharing options...
Guest Loose_Screws Posted March 23, 2004 Share Posted March 23, 2004 I currently have a similar problem which I have been unable to identify. If I press the brakes or turn on the headlights, the amp meter pegs out negative and the car dies. The real problem I have now is that one or more of my injectors are stuck open, which flooded the engine with gas. I checked my fusible links under the hood and found one of them was grounded. I have tried to chase out the wire, but no luck. I hate automotive wiring, and the Z car just adds fuel to the fire. Quote Link to comment Share on other sites More sharing options...
280zrice Posted March 30, 2004 Share Posted March 30, 2004 when i turn on my lights i hear the fuel pump humm a little different pitch and when the lights are off the car smooths out a little bit. i have been looking at the 65 amp alternator and the age of the harness and decided to have my 65amp rewound to produce 120amps at the local auto electrical shop i deal with ,the winding on the stator are within a hairline of the case and it weighs probably twice as heavy as the origanal stator, also cleaning as many connectors of corrosion and looseness due to age / i hear of other z owners upgrading the alternator to a gm single wire or a 95 maxima, . "inginuity is the mother of invention", why have to fabricate unless you improve on the said item or structure , after reinstalling the upgraded alternator the difference in idle with the lights on or off , and the noise at the fuelpump was gone , doing a current ramp on the pump showed no excessive draw after cleaning corrosion,don"t get me wrong ,i also like the newer style of the maxima alternator case have modified my 77 with a few 240sx items, i think i will etch or engrave the case of the rewound alternator, with some sort of scene of a z Quote Link to comment Share on other sites More sharing options...
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