LoneStarS30Z Posted May 23, 2011 Author Share Posted May 23, 2011 Thanks for all the ideas guys. For now it seems that I've "patched" the problem with another new battery. The car no longer drains all it's power and starts on command every time. One thing that I've noticed is the ammeter is pretty jumpy now. Anytime I'm moving at street or highway speeds, the stock ammeter reads a tad past the halfway mark of 0 and 45+. But when I come to a complete stop, it's back to 0, and will skip a hair below 0, I'd say -5 or so when I apply the brakes, turn signals, etc. I also noticed it skipping when it's reading it's high amp reading when I apply the turn signals. I'm under the assumption that it's normal for it to tick slightly when applying brakes (brake lights) and turn signals, but I'm a bit worry about the high reading and what, if any consequences are in store for me that the ammeter is leading on to. What's your take on it? Also thanks again for all the input, and the FSM's should do great for all the wire hunting I need to do. Rsicard, what part of Tucson are you in? I was stationed at DM for about 3 years, just left there May of last year. Quote Link to comment Share on other sites More sharing options...
rsicard Posted May 23, 2011 Share Posted May 23, 2011 Thanks for all the ideas guys. For now it seems that I've "patched" the problem with another new battery. The car no longer drains all it's power and starts on command every time. One thing that I've noticed is the ammeter is pretty jumpy now. Anytime I'm moving at street or highway speeds, the stock ammeter reads a tad past the halfway mark of 0 and 45+. But when I come to a complete stop, it's back to 0, and will skip a hair below 0, I'd say -5 or so when I apply the brakes, turn signals, etc. I also noticed it skipping when it's reading it's high amp reading when I apply the turn signals. I'm under the assumption that it's normal for it to tick slightly when applying brakes (brake lights) and turn signals, but I'm a bit worry about the high reading and what, if any consequences are in store for me that the ammeter is leading on to. What's your take on it? Also thanks again for all the input, and the FSM's should do great for all the wire hunting I need to do. Rsicard, what part of Tucson are you in? I was stationed at DM for about 3 years, just left there May of last year. If the ammeter is jumping there may be a WEAK connection between the alternator and battery positive terminal. At idle the ammeter should go to zero charge or negative in that the battery is being drained. When the engine is revved up the ammeter should smoothly go to a charge indication after starting the engine. Some time after the engine has been started and the engine RPM has been increased for a period of time the ammeter will have a decreased indication but still a charge indication on the ammeter which means that battery is being recharged. The battery is merely a storage reservoir of electrical energy. The purpose of the alternator is to refill the battery reservoir with electrical energy after starting the engine. Then during normal driving the alternator will likely have restored the reservoir and will compensate for other electrical loads on the electrical system such as the ignition system, any lights that are on, the radio, the heater/AC blower etc etc. STRONGLY suggest installing a VOLTMETER in the dash to monitor electrical system voltage. During start a good battery should not go below 9 volts. After starting the engine at idle the voltage should bounce back to 11-12 volts. Then when the engine is revved up the alternator kicks in and the voltmeter should go above +12 volts indicating the alternator is charging the battery. Erratic reading indicate a bad alternator or POOR electrical connections be they field excitation to the alternator or heavy current wiring to the battery. Live in East Tucson. Go past DM many times and for air shows. Many retired Air Force people here as good friends. Love the noise of fighter jets overhead as this is the sound of FREEDOM. Was involved in Aviation Electronics for 38+ years. Electrical systems are EASY in comparison. Several years spent at Learjet as successful Liaison Engineer fixing MANY electrical and electronic problems on Aircraft. Also twice qualified Navy Aircrew-man aboard P2 (Sonar) and P3 (Communicator) ASW aircraft. Now a Amatuer Radio Operator with all three licenses. Attend three different radio clubs here in Tucson. Quote Link to comment Share on other sites More sharing options...
LoneStarS30Z Posted May 23, 2011 Author Share Posted May 23, 2011 Sorry I might have over exaggerated what I meant by the ammeter jumping, it's not erratic, just has a wide range it sweeps to and sticks at when I'm at a stand still versus driving at a constant rate. It's 0 or slightly less when at idle, then reads a lot higher, but a constant reading when moving. I'll take your advice on the voltmeter, I seriously contemplated driving around the block with the multimeter leads still hooked to the battery with the multimeter on the cowl haha. I see why you're so knowledgeable about all this now. I'm a weapons guy on A10s, anytime something hard breaks and troubleshooting/pin checking is involved, it's not the best of times haha. Quote Link to comment Share on other sites More sharing options...
catalak Posted June 23, 2011 Share Posted June 23, 2011 Lonestar, any new updates? i'm dealing with something Very (unfortunately) similar to you. 72 is out of order... going to get a new alt tomorrow and hope that works, otherwise, i'll have to go through all of the recommended troubleshooting steps that are noted in this thread Thanks and hope you sorted everything out -Cat Quote Link to comment Share on other sites More sharing options...
ckolander Posted June 28, 2011 Share Posted June 28, 2011 Not tryin to thread jack but since it seems there's quite a few people of electrical genius reading it, I have an issue. My '79 280ZX seems to be burning/overloading batteries. So far I have gone through 2 batteries. My friend helped me check the readings and my alternator seems to be running low, I've replaced quite a few of the ground wires but I think I've hit a wall. Any advice? Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 28, 2011 Share Posted June 28, 2011 Post a good description of what you measured and how, with numbers. And what does a "burned/overleaded" battery look like and how do you tell? Just trying to help, there's not much to work with in your post. Quote Link to comment Share on other sites More sharing options...
ckolander Posted June 29, 2011 Share Posted June 29, 2011 By burning/overloaded I mean the $250 Exide Orbital Select Deep Cycle Gel Cell battery started smoking out through the vents. Guessin it was hydrogen coming out because it smelled like rotten eggs. As far as the readings go, I don't know exact numbers, my friend was manning the voltimiter while I handled the ignition and fuel side of things. I would like to run the testing again but I'm afraid of putting another battery in it for fear of breaking something Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 29, 2011 Share Posted June 29, 2011 I've seen batteries boil when the voltage regulator has gone bad,letting high voltage through. A short will overheat a battery also. How long did it take before the battery started steaming? If you were working on it for a while, while it was running, then noticed the smoking, it's probably the voltage regulator in the alternator. If it started smoking right away, that's more likely a short somewhere. Quote Link to comment Share on other sites More sharing options...
ckolander Posted June 30, 2011 Share Posted June 30, 2011 I was driving for probably half an hour before it started smoking, guess I need to get the alternator checked out. Thanks Quote Link to comment Share on other sites More sharing options...
hartsel Posted September 26, 2011 Share Posted September 26, 2011 my car had this nasty little fuse box that this 12 gauge or so wire was actually from the alternator to this box then to the battery. and the fuses were replaced by some jumper wires. and one of those wire was dirty and not allowing the alternator to charge the battery except on occasion. look for that fuse box. Quote Link to comment Share on other sites More sharing options...
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