charging issues
charging issues I start my car and the alternator gauge reads about 10 amps. My 'check gauges' light comes on and I give it gas and it goes away, but the amps only raise about 1 amp, just enough to shut up the light. When I drive it doesn't go up more than that 1 amp. I have a brand new (6 months old) red top that I replaced because the gauges would spike up when starting the car....that issue has since stopped after putting the red top in so I don't think it is related.
I did a search and some guy said to read the battery terminals with a multimeter when the car is running but I don't want to shock the **** out of myself doing this, is this legit or bogus info? Is there any way to test the alternator other than pulling it and going to kragen? Does this sound like an alternator issue? Also I tried the other battery (the one that made the gauges spike on start up) and it read low too and the amps didn't move much with that one either.
btw the car has 40k on the clock and gets started at least once a week.
I did a search and some guy said to read the battery terminals with a multimeter when the car is running but I don't want to shock the **** out of myself doing this, is this legit or bogus info? Is there any way to test the alternator other than pulling it and going to kragen? Does this sound like an alternator issue? Also I tried the other battery (the one that made the gauges spike on start up) and it read low too and the amps didn't move much with that one either.
btw the car has 40k on the clock and gets started at least once a week.
Oh, I forgot to mention I put an under drive pulley on about 500 miles ago. Haven't had a charging problem until yesterday. In fact before this whole thing happened the needle was reading more to the right of the amp gauge then the middle, even after the pulley swap.
First, it's a volt gauge. It's measuring the voltage, which should be close to 14 volts when the car is running. Next thing is you will not shock the **** out of yourself checking the voltage with a multimeter when the car is running. I don't recommend holding both terminals, but putting a multimeter on the terminals won't hurt you at all.
What it sounds like is your exciter wire coming off the alternator may be bad. It goes to the PCM and essentially tells your alternator when to charge and how much. It may be bad, or have a short in it, which is what's causing your charging / battery issues.
What it sounds like is your exciter wire coming off the alternator may be bad. It goes to the PCM and essentially tells your alternator when to charge and how much. It may be bad, or have a short in it, which is what's causing your charging / battery issues.
well it died.
after not driving the car all week I took it to auto zone to see if they can test anything (it started fine but was running at 1/4 on the volt gauge). The guy said the battery read 10.5 and it needed to be charged and retested. I started to drive off and in a matter of 2 minutes (still in the parking lot) the volt gauge went from 1/4 to zero so I parked it and tried to restart now it clicks.
The battery was made 03 07 and is a red top. I tried my old battery thinking it may be the red top and same thing, clicks but nothing else. From what I can see of the wires they look good, not burned or frayed or any visual evidence of failure. I'm going to take the alternator off and I guess I'll have it tested. I got the 3 front bolts out then this guy says "should have bought a ford" and got into his rustang and drove off. I decided to get it towed before I kill the next comedian.
after not driving the car all week I took it to auto zone to see if they can test anything (it started fine but was running at 1/4 on the volt gauge). The guy said the battery read 10.5 and it needed to be charged and retested. I started to drive off and in a matter of 2 minutes (still in the parking lot) the volt gauge went from 1/4 to zero so I parked it and tried to restart now it clicks.
The battery was made 03 07 and is a red top. I tried my old battery thinking it may be the red top and same thing, clicks but nothing else. From what I can see of the wires they look good, not burned or frayed or any visual evidence of failure. I'm going to take the alternator off and I guess I'll have it tested. I got the 3 front bolts out then this guy says "should have bought a ford" and got into his rustang and drove off. I decided to get it towed before I kill the next comedian.
You don't have to take the alternator out to test it. Simply leave the battery in the car and put it on a low current charge for 24 hrs. Then test the voltage on it with the multimeter. Then the car should start up fine. When you read the voltage before starting, write it down. It should be about 12.6 volts charged and no current drain on it. Then start the vehicle and read the voltage at the battery again. It should be over 13 volts if it is not, take your multimeter and read the voltage from the alternator chassis to the output post on the back of the alternator. If you don't get good voltage at the battery, but do get it at the alternator, then you have a probable open circuit between the alternator and the battery. If you get good voltage at the battery with the engine running, then begin turning on accessories such as your heater or a/c on high, rear defrost, high beam headlights or wait until the electric fans come on. You just want to create a load on the alternator and see if it can maintain over the battery's 12.6 volts. Since you have an underdrive pulley on it ( which I think isn't worth slowing down the water pump and alternator for a few HP ), rev the engine to around 2k rpm while you have these accessories on and it should produce 13v or more with the engine at that speed. If it does not, check the output at the alternator again. If you have more than 2 or 3 tenths of a volt higher at the alternator than the battery, your trouble is again in the wiring between the alternator and battery. You can replace that wire with a 8ga wire and some good connectors if need be. PM me if you have any other specific questions I'll be happy to help.
Good luck.
Good luck.
OK I'll give it a whirl. I'm not an electrician so I really hope I don't end up like ted bundy doing this. I have to get it towed anyway and all I have to do is reconnect the drive belt when it gets back to my house. The alternator is only 1/2 out (3 bolts)
Thanks
Thanks
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I have worked on cars for 20 years and specialized on the electrical side and you must know that I have seen a ton of people take their alternator to the local parts house and be told their alternator is bad when it is good and good when it is actually bad. Same with batteries. I forgot to mention, when you are measuring voltage differences between the battery and alternator, you can test the ground by putting the positive lead across the alternator and the negative to the alternator chassis and then move the negative lead to the battery ground. If you see a big difference there, then you have a bad battery ground cable or connection. You won't get shocked. I quit working on cars except for the weekend warrior stuff and now work for the phone company and it is 52 volts dc. That doesn't even hurt unless you are sweating really bad when you touch it and it's still only a mild irritation.
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Verdad Gallardo I have worked on cars for 20 years and specialized on the electrical side and you must know that I have seen a ton of people take their alternator to the local parts house and be told their alternator is bad when it is good and good when it is actually bad. Same with batteries. I forgot to mention, when you are measuring voltage differences between the battery and alternator, you can test the ground by putting the positive lead across the alternator and the negative to the alternator chassis and then move the negative lead to the battery ground. If you see a big difference there, then you have a bad battery ground cable or connection. You won't get shocked. I quit working on cars except for the weekend warrior stuff and now work for the phone company and it is 52 volts dc. That doesn't even hurt unless you are sweating really bad when you touch it and it's still only a mild irritation.
I'm going to partially hijack this thread a little bit, as I think it might help the original poster as well as myself.
I've got a charging issue as well. I'm getting a P1637 code which is the L-terminal fault which is the wire going to the top of the alternator, which I'm guessing tells the alternator when to charge and how much.
I check the wire the other night for continuity and it's fine, in the range of 0.01 ohms resistance, minimal, definitely not a broken wire. Checked the harness going into the alternator, cleaned it up, and again no problem. But as I drive, and hit ~3500 rpm with half to full throttle, the voltmeter will start to drop, or if I turn on the rear defroster with the headlights on, the gauge dips, but comes back to 13'ish after I rev the car a little.
Is this an issue of the alternator going bad or could it still be the wire going into the top of the alternator? I'm going to replace all of the cables as I have a little bit of corosion on the positive terminal. Nothing too dramatic, but enough to warrant a replacement.
Thanks.
Oh, I forgot to mention that the battery is fine. It holds a charge really well as my car sits for somtime 2-3 weeks without being driven and cranks up fine. After sitting for a couple weeks, it's still at 11.9-12.2 volts.
Here is the entire troubleshooting guide on the L-terminal circuit. If it is throwing the code, this will help you determine if it is the alternator or something else.
http://www.gearchatter.com/viewtopic...?view=previous
http://www.gearchatter.com/viewtopic...?view=previous
Last edited by BLOWNBLUEZ06; Nov 17, 2007 at 12:21 PM.
blownblue, I sent you a pm
I'm a little confused on where the alternator outpost is and what the difference is between the alternator and the alternator chassis.
My volts are fine before starting and at idle, but when I put the accessories on they drop to about 11.5.
Thanks
I'm a little confused on where the alternator outpost is and what the difference is between the alternator and the alternator chassis.
My volts are fine before starting and at idle, but when I put the accessories on they drop to about 11.5.
Thanks
