I'm chasing a battery/electrical issue. My question is would a bad battery cause a car to stall at idle, the theory being that at 800 rpms or so the alt is not charging enough for the batt to maintian a spark for the motor? I keep having to jump- charge my battery and the alt is putting out 14 volts, but under 1000 rpms while in gear she died on me yesterday and I could not start it up, but needed a jump, once running I was able to get home. I was adujusting my valves and just bumping the starter to turn it over a little at a time caused the batt to run down. would it cause it to stall as well?
I did and keep having to, if it sits for a couple of days it needs to be charged, my concern is the stalling, and could that be the battery?
sure it can , here at the shop we get cars that have been setting for long periods of time and the batteries are dead, just a jump start doesn't always work. Some need new batteries
try a diode in the exciter wire. you may have a drain there. the diode will let the voltage go in the alt but will not let voltage come out thru the exciter wire. ?
Yes, particularly if you have electronic ignition or worse yet, if you have MSD or some aftermarket ignition. They tend to be less tolerant of low voltage. In my most recent case, the vehicle would crank but would lack enough juice to fire the ignition at the same time. After I let off the starter, it would start. What finally sealed the deal was after running about 15 minutes, I shut it off and it wouldn't crank any more. My yellow top optima was 14 years old at that point. Insufficient grounding and/or bad crimps will make this issue worse. A bad condenser in a points system will give you similar fits. I have also had issue with debris in the idle circuit of the carb causing such things. On the Holley and the Edelbrock, I would unscrew the needles and squirt in carb cleaner. This would just prolong the need for a rebuild a week or two. Turn the needles in first and count them.
sounds like a leaking Diode in the Alt or a dead battery. The battery plates start to corrode and the corrosion touches inside and shorts out internally.
I'm going through the same thing- with good output, new battery, alt and voltage regulator. It's somewhere in the wiring (which is shoddy and taped and a mess at best). Good luck- something that has helped me is a good wiring diagram- which if you google your year and make/ model with the word 'wiring diagram' you will find some good stuff. -Screws
OK now here is the other thing, i have a 3 wire GM alt with 12v from the batt on the starter to the batt post on the alt, and #2 jumped back to the batt post, and #1 to the ign switch WITHOUT a diode or lamp...so me thinks that this is part of the problem???
Might be part of the problem, or maybe not. First off, have you put a battery charger on the battery and let it charge back up fully after you ran it down playing with the valves? how old is the battery? Does the car need a jumpstart if you let it sit, with the battery disconnected? If the battery is old and tired, get a new one before you waste too much more time. If the battery is not very old, and just needs a good charge, do that first, then see what happens.
If the alternator is really putting out 14v when you're driving around (14v measured at the battery itself), it should start right up without a jump when you shut it off. Sounds like the battery is getting tired, I'd try a new battery first.
charge your battery with it disconected and let it sit over night, then check to see if stays charged up, your alt. should be charging at 800 rpm's
Get the battery tested before spending any money on possible fixes. Old batteries may not hold a charge. Anyplace that sells them will test it for you. If it comes up iffy, replace it. With 14 Vs it sounds like your alternator is charging.
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