# Charging system problems, please help!!



## alank2 (Dec 29, 2006)

Hi,

I've got a 1986 Stanza wagon that I've replaced the alternator on a couple times and it always seems to come back to these sorts of problems - in time.

It was working well, and then I heard the belt slipping one day. Right afterwords the voltage dropped from 14 to around the battery voltage (12.5). I always have a voltmeter going in this car because of this problem.

The other night I took it out for a quick trip to someone's house. Voltage was good all the way there. On the way back it went from over 14 back down to 12, then dropping, 11.8, 11.7, 11.6, and so on. I know from past experience that this means it is pulling power from the battery and eventually it will run out of power and barely run. I made it home and put the battery on the charger.

Today I went out to do some testing. I checked the belt and it seems plenty tight, maybe just small a little loose, but the alternator is pressed almost out as far as the adjustment will go. This one doesn't have a thing to grab with a ratchet so I can hold it tighter while tightening the bolt, I am assuming it has to be wedged with a screwdriver to tighten.

I sprayed some of this belt dressing stuff on it thinking if it was a little slick this stuff might give it some tacky-ness. I sprayed a little, ran it for a few seconds, spray a little more, and ran it again. I turned the Stanza on and the voltage was in the low 14's at idle which is great. But, I decide to turn the lights on and the cabin fan to see what affect it would have. Even at idle (600 or so rpm) both of these on immediately overwhelm the car and pull it down into the low 12's and high 11's.

What does this tell me? Bad alternator possibly? It is probably the 3rd replacement alternator we've had in this car in the last 5 years.

What about the voltage regulator? I think it is external on this alternator, some sort of small metal part that hooks on to the alternator when the wire is connected to it. Could this be bad? What are the symptoms when it is?

I could take the alternator off and take it in for testing, but I am open to any and all ideas you guys might have.

Thanks,

Alan


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## bikeman (Dec 26, 2006)

If the belt seems that it needs to be tighter but can't be pulled any further then I would suggest that you get a slightly smaller belt on there so that the alternater can move and adjust properly (maybe the wrong one on there now or it's stretched, compare a new "stock" belt to it). That's where I would start, it may be stretched and is slipping. I'm pretty sure that the alternater and regulater is all in one.


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## alank2 (Dec 29, 2006)

Hi,

Thanks for the info, I'll start with that. Do you have any idea what the silver metal electronic part would be? Maybe some sort of conditioner to prevent electrical noise for the radio or something?

Thanks,

Alan


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## bikeman (Dec 26, 2006)

I would think it's a noise surpresser as well.


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## sportcoupe(turbo) (May 25, 2007)

you can test the alternator yourself by starting the car and pulling off the positive bettery terminal and if the car dies its your alternator is bad (or possibly your belt as bikeman said) and yeas the voltage regulator has been united with the alternator since 1970's thats when nissan changed it. look at all the alternator connections and make shure non of them are loose hope this helps.


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## alank2 (Dec 29, 2006)

Hi,

Thanks guys. I think the problem is slipping. I got in there and I was able to pull on one of the alternator fan ends and move it slightly. The belt is already pretty tight so I think it is just too slick. I made the mistake of trying some belt dressing on it a few weeks ago, I didn't realize this stuff isn't the best way to go about it.

What should I do now? The belt is the third one in, so to get to it I will have to remove the other 2 as well which I'll have to figure out how to do. Should I get the belts off and clean up the pulleys with brake cleaner to make sure they are grease/slick free and then put new belts on?

Is there any cheaper workable trick I can do to give it some more grip without pulling the belt?

Thanks,

Alan


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## bikeman (Dec 26, 2006)

It sounds like the belt is tight enough, you don't want to over do it and make it too tight. I've used belt dressing and it won't make your belt slip. How is the battery itself? If you have a bad/weak battery it will make the alternater work too hard, having to constantly charge it. Is your gauge accurate? Maybe test with a good volt meter when idle and with load, normal to drop a little with everything on, especially headlights and full fan blower, shouldn't drop below 12v though. Make sure terminals are tight and clean with a good ground. It just may be another alternater, are you getting re-built units or used ones?


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## alank2 (Dec 29, 2006)

Hi,

I replaced all 3 belts and cleaned the pulleys so am pretty sure they aren't slipping. If I turn on the lights, blower, and air it seems to overwhelm the alternator and the voltage drops to low 12's and sometimes into the high 11's. I took the alternator off and took it to a local place and they said it tested ok. I asked them how much current they tested it with and they said 15A, but it is 70A rated. Should I take it somewhere else for testing? If the alternator is good, what else could I troubleshoot?

The negative battery connection has one heavy gauge wire that goes to the frame, and then it bolted onto the motor block.

The positive battery connection has 3 wires. One heavy gauge that looks like it goes to the alternator and it bolted on to a bolt terminal, it splits near the alternator and looks like it goes to some sort of plug in the engine. There are also two other wires coming off the battery, one is a little heavier than the other, but I don't know where these two go. The alternator also has some blade connections (2) that plug in and again, I am not sure where these go.

I guess where I am going with this is, could I have a bad connection somewhere? This car is old and I've had issues with wiring with it.

All tips and ideas welcome,

Alan


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## bikeman (Dec 26, 2006)

Take it into a good shop for a proper AVR test, maybe all is fine and your gauge is not 100% accurate. It's normal for voltage drop when everything is on on a car that age. Have you had issues where it has actually died because of this?


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## alank2 (Dec 29, 2006)

Hi,

I've had issues with this car for years electrically. I keep putting batteries into it and trying to fix it. I took the alternator to NAPA today and they tested it as well and also said it is good. They thought perhaps I have an excessive load from something with a short in it, etc. When I apply the break pedal, it does seem like a bigger draw than I would expect. Any ideas of where I should begin? Those two wires coming off the positive part of the battery are I think 8 gauge and 10 gauge. Do these go to the two distribution panels (one outside, one inside)?

I may put my DC clampmeter on them and start measuring to see what I can figure out...

I wonder if the RPM is part of my issue here as well. It wants to run at 500 rpm when in drive. In the past when I adjusted the idle I made it so the throttle cable was not applying any tension and then I adjusted the idle screw (I guess this is what it is called). It is a silver colored screw that faces directly up, with about a half inch wide head. Counterclockwise increases idle, clockwise decreased idle. It does not seem to affect the speed when in drive, mostly when in park or neutral. If I have it too low though, it wants to stall while switching into gear.

I appreciate your help and advice Bikeman!

Thanks,

Alan


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## alank2 (Dec 29, 2006)

Hi,

I got the alternator put back on. I went ahead and pulled wiggled and removed/reinserted all the fuses/relays just to make sure they were getting a good connection. I put my DC clampmeter on the two leads coming from the battery that don't go to the alternator and found out this:

Key set to Accessory = 0.5 A current use
Key set to On (Engine off) = 4.1 A current use
Key set to On (Engine on) = 6.0 A current use
Fuel Pump = 3.0 A current use
Headlights = 14.3 A current use
Brake Lights = 9.8 A current use
Windshield Wiper = 6.0 A current use
Fan Level 1 = 3.3 A current use
Fan Level 2 = 5.0 A current use
Fan Level 3 = 9.7 A current use
Fan Level 4 = 15.9 A current use
Rear Wiper = 1.5 A current use
Interior Light = 0.5 A current use
Radio = 0.6 A current use

What do you think of these numbers? My stanza has the two rear brake lights and the top brake light as well, all bulb, does 9.8 A seem high on this? The car also has cruise control so I think there are two switches on the brake pedal. Do you think I am getting any sort of shorting with the brake light system?

I really think my issue is when the car is stopped and it has low engine RPM while in drive. The engine runs around 500 rpm and this is not enough power for the alternator to keep its voltage up. As soon as I am driving, all is well.

I guess this means I need to figure out why the "in drive" rpm is running 250 rpm lower than it should be. I think in another post you told me it should run 750 in drive, 900 in park. I am running 500 in drive, 1000 in park. The idle screw seems to affect the "in park" rpm only and does not seem to affect the "in drive" rpm.

Thanks,

Alan


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## sportcoupe(turbo) (May 25, 2007)

I'm pretty shure you should have the rpms at about 750 when at idle so in park and nutral on manual cars the idle should be 900, when in drive it should be 750 but may drop a little bit that should be ok (500 may be too low ) what you can try doing is adjust the screw back to around 750 and adjust your tps sensor which is on the other side of the screw.


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## alank2 (Dec 29, 2006)

Hi,

I found a vacuum hose with a break near the black cylinder in the upper right area that is held by some sort of spring thing. I cut off the bad part and put it back on. Not sure if it made any difference.

I figured out I read the tach wrong. It is running 750 when in drive and around 1100 when in park which is still a little high, but I think workable.

The last thing I'm going to do is find the computer and do the oxygen sensor test to make sure it is working properly.

Thanks for the help,

Alan


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