[ztweny8]

Alright, I was going to test the charging system with my multimeter, but when I went to use it I found out it doesn't have a 12V setting. So I decided to just boost it again and play with wires, see if any were loose or corroded etc.

Once I got it running I noticed a noise, not sure if it was always making that noise, or only when the problem started. But I made a video of it none the less because it didn't seem right. It sounds like a fire alarm, but with someones hand muting it, and its coming from the ignition coil. It was kind of hard to hear in person but you can hear it clearly throughout the whole video, even when i'm inside the car.

I also took some footage of how the battery gauge is behaving when the car is revved. And then I took some of my A/F gauge. I think this car may still have the tune from when it had a centrifugal blower on it. Or I remember reading that if its just a shortband A/F it will be nothing more than a light show, and behave erratically like that, so maybe its just that.

Anyways, would the ignition coil have anything to do with what I'm experiencing?

Mustang :: MVI_0334.flv video by Ztweny8 - Photobucket

Mustang :: MVI_0334.flv video by Ztweny8 - Photobucket

[1slo5.0]

Originally Posted by ztweny8 Alright, I was going to test the charging system with my multimeter, but when I went to use it I found out it doesn't have a 12V setting. So I decided to just boost it again and play with wires, see if any were loose or corroded etc. Once I got it running I noticed a noise, not sure if it was always making that noise, or only when the problem started. But I made a video of it none the less because it didn't seem right. It sounds like a fire alarm, but with someones hand muting it, and its coming from the ignition coil. It was kind of hard to hear in person but you can hear it clearly throughout the whole video, even when i'm inside the car. I also took some footage of how the battery gauge is behaving when the car is revved. And then I took some of my A/F gauge. I think this car may still have the tune from when it had a centrifugal blower on it. Or I remember reading that if its just a shortband A/F it will be nothing more than a light show, and behave erratically like that, so maybe its just that. Anyways, would the ignition coil have anything to do with what I'm experiencing? Mustang :: MVI_0334.flv video by Ztweny8 - Photobucket

Sounds like the coil is arcing. Open the hood at night and see if you can see a light show. The volt gauge looks like every fox body I've owned with underdrive pulleys. They have weak alternators from the factory. They are only 75 amp.

[ztweny8]

Originally Posted by Darrell Sounds like the coil is arcing. Open the hood at night and see if you can see a light show. The volt gauge looks like every fox body I've owned with underdrive pulleys. They have weak alternators from the factory. They are only 75 amp.

I know about the weak factory alternators, but should it be THAT low with underdrive pulleys? Before this started happening I don't think it was that low.
If I started it now I would have pissed off neighbors lol, I will earlier tomorrow night though.

Would the coil arcing cause my problems?

[jtyson8602]

yes the ud pulleys will make that much difference on the alt. you can do 2 things about this. put the stock pulley back on the alt or go ahead and do the 3g upgrade. Its worth it anyway in the long run. and yes the coil arcing can cause problems, most importantly FIRE! also can cause shorts and blown fuses but not typical of battery drain. I used to have the same problem with my car and after I did the 3g upgrade problem was gone. now if you want to test your draw with your multimeter, the setting you used is fine. If you can read differences in the draw on different things when tested its fine. you see current change even if youre not reading voltage. you can also check your ohm reading if your multimeter has the setting (looks kind of like a horseshoe) and it will tell you if you have a break in the circuit.

[1slo5.0]

Originally Posted by ztweny8 I know about the weak factory alternators, but should it be THAT low with underdrive pulleys? Before this started happening I don't think it was that low. If I started it now I would have pissed off neighbors lol, I will earlier tomorrow night though. Would the coil arcing cause my problems?

The coil arcing won't cause your battery to drain over night because the car is shut off. Yes, underdrive pulleys will cause the gauge to sit that low because the factory fox body alternators are inadequate to begin with. I wouldn't be too concerned about what it does at idle, unless you spend hours and hours idling. A 3G with underdrive pulleys does the same thing. Try pulling the rectangle 3 pin connector off the alternator and let it sit over night. See if your battery still goes dead. Those connectors commonly short out internally so that is something else you can try and possibly eliminate as a problem. I would also try disconnecting your battery over night, then reconnect it the next day and see if your problem still exists. If the battery drains over night with nothing hooked to it, then you've found your draw.

[ztweny8]

Originally Posted by Darrell The coil arcing won't cause your battery to drain over night because the car is shut off. Yes, underdrive pulleys will cause the gauge to sit that low because the factory fox body alternators are inadequate to begin with. I wouldn't be too concerned about what it does at idle, unless you spend hours and hours idling. A 3G with underdrive pulleys does the same thing. Try pulling the rectangle 3 pin connector off the alternator and let it sit over night. See if your battery still goes dead. Those connectors commonly short out internally so that is something else you can try and possibly eliminate as a problem. I would also try disconnecting your battery over night, then reconnect it the next day and see if your problem still exists. If the battery drains over night with nothing hooked to it, then you've found your draw.

alright, sounds good.

[ztweny8]

well the new ignition coil doesn't sound like an air compressor lol, so that's good. I boosted it and its running right now. Held it at 2000 rpm for a little bit and I'll do that again before I turn it off. And We'll see if it starts again later on.

[92twotone]

you should check the negative cable itself...i run the optima redtop on mine also and btw have noo problems at all with it clearing my 2.5" cowl hood. Check the mounting tray maybe something is tweaked or its not sitting right idk thinkin out loud. I have a 1200watt amp that stresses the alternator a lot. I was having a similar charging problem and thought it must be the alternator...it wasnt. The terminal end on the negative battery cable had a crack on the bottom side of it from being old and getting tightened and losened up so many times. it was like a $10 napa fix and before i ripped the whole car apart to build my motor and replace my tranny it was charging just fine. good luck.

[ztweny8]

Originally Posted by 92twotone you should check the negative cable itself...i run the optima redtop on mine also and btw have noo problems at all with it clearing my 2.5" cowl hood. Check the mounting tray maybe something is tweaked or its not sitting right idk thinkin out loud. I have a 1200watt amp that stresses the alternator a lot. I was having a similar charging problem and thought it must be the alternator...it wasnt. The terminal end on the negative battery cable had a crack on the bottom side of it from being old and getting tightened and losened up so many times. it was like a $10 napa fix and before i ripped the whole car apart to build my motor and replace my tranny it was charging just fine. good luck.

I ended up fixing the clearance problem with the battery. The tray was set as high as it could be, so that was an easy fix. Good thought about the connection too, I'll give it a try. Cant go wrong for $10

[ViperblueGT]

you need to use your dmm and check the draw on the wire running from your battery to your alternator if it has too much restistance in it than it could be a problem with that wire holding back on the alternator charging the battery ...and darrel give the guy a fuckin brake .....i know i'm a newbie on this site but shit everyone starts at nothin and has to work their way up...the way he started with havin the alternator is perfectly fine....thats a real easy and simple way to knock out possibilities...

[ztweny8]

Just did some more testing.

While boosting the battery read 13.4 volts

Once I started it and removed the booster cables it read 11.7 volts

When revved to 1500 RPM it read 14.3 or so volts. Which is normal with underdrive pulleys correct?

When turned off it read a steady 11.7 again

Tried to start it 2 minutes later with the battery still reading around 11.7 volts and all I got was the "not enough power to turn over buzzing sound". Which took the battery down to 10.4 volts.

I'm going to wait an hour or 2 and check the battery again, see if its drained itself.

My question is, shouldn't 11.7 volts be enough to crank it?


And if their are any other test I can do with the multimeter, please tell me exactly where I am to put the negative and positive test leads, and what setting etc. , I'm slowly learning how to work this thing lol

[1slo5.0]

Originally Posted by ztweny8 Just did some more testing. While boosting the battery read 13.4 volts Once I started it and removed the booster cables it read 11.7 volts When revved to 1500 RPM it read 14.3 or so volts. Which is normal with underdrive pulleys correct? When turned off it read a steady 11.7 again Tried to start it 2 minutes later with the battery still reading around 11.7 volts and all I got was the "not enough power to turn over buzzing sound". Which took the battery down to 10.4 volts. I'm going to wait an hour or 2 and check the battery again, see if its drained itself. My question is, shouldn't 11.7 volts be enough to crank it? And if their are any other test I can do with the multimeter, please tell me exactly where I am to put the negative and positive test leads, and what setting etc. , I'm slowly learning how to work this thing lol

Charge the battery for 10 minutes or so and then unhook everything from it including the negative and positive battery cables. Check the voltage. Wait an hour and then check the voltage again. If the voltage drops in that hour then you have a junk battery and you have found your draw.

[ztweny8]

Originally Posted by Darrell Charge the battery for 10 minutes or so and then unhook everything from it including the negative and positive battery cables. Check the voltage. Wait an hour and then check the voltage again. If the voltage drops in that hour then you have a junk battery and you have found your draw.

In the process of that right now. Thanks

[ztweny8]

Had some people come over and do some testing on the car. We determined that my battery is toast. Did some testing with the multimeter and found that when running, the voltage at the battery was 11.7ish, when revved it went up to 14.3 or so like I observed before.

They told me that wears on the battery and that's probably why the battery is toast. We put in a known good battery, and at idle it read 12.~ and the volt gauge in the dash sat just under half way. We adjusted the idle to 900 rpm, and at idle it puts out a steady 13.4.

We were told that you can buy street application underdrive pulleys, and race application. They figure I have the race application ones and since in a race car its at full throttle 90% of the time its ok, but because I have to idle being that its a street car, they don't put out enough to keep the battery healthy.

Good thing my battery has a 3 year warranty lol.

edit: and I did have the battery tested and it passed, but they told me they didnt use a proper load testing machine.

[1slo5.0]

Originally Posted by ztweny8 Had some people come over and do some testing on the car. We determined that my battery is toast. Did some testing with the multimeter and found that when running, the voltage at the battery was 11.7ish, when revved it went up to 14.3 or so like I observed before. They told me that wears on the battery and that's probably why the battery is toast. We put in a known good battery, and at idle it read 12.~ and the volt gauge in the dash sat just under half way. We adjusted the idle to 900 rpm, and at idle it puts out a steady 13.4. We were told that you can buy street application underdrive pulleys, and race application. They figure I have the race application ones and since in a race car its at full throttle 90% of the time its ok, but because I have to idle being that its a street car, they don't put out enough to keep the battery healthy. Good thing my battery has a 3 year warranty lol. edit: and I did have the battery tested and it passed, but they told me they didnt use a proper load testing machine.

Did you ever test the battery the way I told you? That is a quick, easy and for sure way to test it.

As far as the underdrive pulleys go, I've never used a set of "street" pulleys. Most of the time I used March or BBK. I've never had charging problems even with an electric fan and electric water pump. I doubt the pulleys had anything to do with your battery going dead.

[1slo5.0]

Originally Posted by ztweny8 I did have the battery tested and it passed, but they told me they didnt use a proper load testing machine.

Yeah, I've run into that too. I bought a battery for my Suburban at Advance Auto Parts. It failed within a year. I tested the battery at home (I have a couple tools). I took the battery out of my race car and put it in my Suburban so I could go to Advance Auto Idiots to exhange it. They tested it with their machine and the guy says "I gotta charge it up fully first". I told him I had the battery on the charger all morning. He said "well its dead now so I have to charge it". I said "no shit its dead, the battery is junk". He says "we'll see about that". After a couple minutes of charging he tests it and says "test passed, the battery works great". I argued with him and explained to him how the battery has a dead cell and will not hold a charge. He said the battery is fine. I explained to him how I did several thousand dollars in business at that store every year and if someone competant wasn't going to come and help me I was going to take my business across the street. He looked at me like I was stupid and said "okkkk". I left the battery in the store told him to shove it up his ass and I went directly across the street to Auto Zone and bought a new battery. I haven't been back to Advance Auto since. If they are going to hire idiots like that and/or encourage them to screw customers then I'll go else where.

Ok, rant over. That was like 3 years ago and still pisses me off.

[HMUSN]

look dude.. I told you the battery was good. Deal. I even tested it.

[ztweny8]

Originally Posted by Darrell Yeah, I've run into that too. I bought a battery for my Suburban at Advance Auto Parts. It failed within a year. I tested the battery at home (I have a couple tools). I took the battery out of my race car and put it in my Suburban so I could go to Advance Auto Idiots to exhange it. They tested it with their machine and the guy says "I gotta charge it up fully first". I told him I had the battery on the charger all morning. He said "well its dead now so I have to charge it". I said "no shit its dead, the battery is junk". He says "we'll see about that". After a couple minutes of charging he tests it and says "test passed, the battery works great". I argued with him and explained to him how the battery has a dead cell and will not hold a charge. He said the battery is fine. I explained to him how I did several thousand dollars in business at that store every year and if someone competant wasn't going to come and help me I was going to take my business across the street. He looked at me like I was stupid and said "okkkk". I left the battery in the store told him to shove it up his ass and I went directly across the street to Auto Zone and bought a new battery. I haven't been back to Advance Auto since. If they are going to hire idiots like that and/or encourage them to screw customers then I'll go else where. Ok, rant over. That was like 3 years ago and still pisses me off.

Yeah, that's just like the alternator ordeal I went through. 3 part sources (Canadian parts chain similar to Napa, Autozone etc). And at the 2nd one the guy put it on the test machine wrong and the cooling fan on the alternator started grinding away at the test machines bracket.

He turns around while its still spinning and sounding like an angle grinder and says "did it sound like this at the other part source?". I flipped out. I'm calm and cool 99% of the time. My friend was suprised how I acted lol