Hey guys, Start off with the problem in as much detail as possible, it's pretty simple really, car runs fine after warming up, turn on radio idle goes down a little, turn on fog's idle goes down a little more, turn on heat and idle goes down even more, try the headlights and risk stalling the car.

details on the car, LS/vtec pretty much fully built all motor, really the cams make it idle funny, but have been tuned to stay pretty steady and not surge and jump at all, unless idle is drained by the electrical current.

I do realize that this happens on pretty much all cars, it's just very very aggresive on my certain car, it nearly stalls out when I have the headlights on, and am at a light holding the brakes.

I replaced the battery with a battery that has more CCA and AH, thinking maybe that might do the trick, didn't help at all. My radio has a feature that can check the volt meter on the battery and display it on the headunit ( I used to think it was bs and just for the Cool Factor and never used it, but i actually checked the voltage with a real volt meter, and the damn radio thing is correct.) What the meter is reading is 13.8-13.9 while the car is running with no extra devices turned on, when the fogs go on it's a constant 13.6-13.7 add the headlights it drops to about 13.3-13.4 add the heat and maybe brakes it will be approx. 12.9-13.0 sometimes it goes to less.

what i think is, not the battery, not the alternator, maybee i should just bump my idle up and it would fix the problem of course, but i would be idling at 2k, so any input before I do that would be greatly appreciated. thanks, Brian.

 

either ur alternator or the wire goin to the alternator or a bad ground to engine or batt

 

I will check ground wire, and alternator connections tonight, i forgot about the problem since the car is hiding from the cold now, but good idea, thanks.

 

I don't think your problem is an electrical one. It is purely a matter of your engine not putting out enough hp at idle to turn the alternator as the electrical load increases. As you probably know, the alternator becomes physically harder to spin as the amount of power drawn from it increases. I would try fine tuning your idle more, perhaps by adding some timing, and making sure the afr is not too lean/rich and causing light misfiring.

Just out of curiosity, how much vacuum does it pull at idle? If it is low, that would be an indicator that your idle needs some work.