Possible alternator problem

DavzGN

Well-Known Member
I have an odd charging problem I am hoping someone might have a suggestion on.. A couple weeks ago I had a bad battery (4 yr old) that caused some problems starting and driving. I tried charging it and the battery charger said battery was bad so I took it in for testing and they replaced it. Since the new battery, I had a dead battery one morning and last night it quit a mile from home. Last couple miles it was running, I noticed the headlights were dimming. So I shut off all the electrical draws I could. Came to a stop sign and turn signals wouldn't flash and headlights dimmed more. The weird thing is that when this starts to happen, the first thing I notice is my wideband gauge reading dropping to 7.4. If the O2 readings jump back to the normal operating ranges it seems to be okay then.

The volt light doesn't come on so the alternator should be isn't charging I know works because it comes on with Key on and goes out when started as it should.

First time I had the problem it was due to the bad battery. Since then I think I've the problem twice and the problem has been occurring only at night, so I am wondering if the problem might be that the Alternator is charging enough to turn off the volt light but not enough to charge everything when the headlights are on in the evening.

My plan of action is to check all the battery cables and grounds. Get the alternator tested and see where I am at. Also check the 02 sensor connections and the HID low beams to see if there is some kind of problem with them.

Any other suggestions would be really appreciated.

David
87GN
 
Sounds like you are on the right track. If you don't have a volt meter go buy or borrow one.

Charge the battery and check voltage. Start car and it should go up. Turn on bright headlights, fan, and defroster. Voltage should still be above your non running number.

Mark E.
 
Well I finally picked up a new multimeter and did some testing. At idle with headlights, fan, and 4 ways on the volts dropped to about 12 volts so I am thinking pull the alternator and get it tested.

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Got a 140 amp impala SS alternator, I had to grind on the case a little to get the short upper bolt in. As the case hit the gusset on the aluminum bracket. Got a new Delco one for about 120. Get 14.3 volts now with the lights and fans on

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Got a 140 amp impala SS alternator, I had to grind on the case a little to get the short upper bolt in. As the case hit the gusset on the aluminum bracket. Got a new Delco one for about 120. Get 14.3 volts now with the lights and fans on

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Is it a hard job to grind the metal on the alternator? What tools did you use
 
If I remember correctly,. It was just rounding a corner a little in one spot. I think I used a Dremel but it's been a while. I'll see if I can take a quick picture tonight when I get home.

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If I remember correctly,. It was just rounding a corner a little in one spot. I think I used a Dremel but it's been a while. I'll see if I can take a quick picture tonight when I get home.

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Thanks for the help cause I'm about to buy a new alternator so if it's not to
Much for me then I'm gonna go for it so I hope to hear from you,btw what year impala alt did you usr
 
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It is for an 95 impala. I ordered an AC Delco 335-1048. It was about $120 on Amazon.

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The edge of the case behind support where the arrow is had to ground a little get the bolt in at the top of the support. The bolt was very close to going in maybe a couple millimeters off and didn't want to force it and strip the threads. It was only tiny bit of grinding that I had to do. Just the variation in the case and bracket might allow some people to install it without any grinding
b7b1e9e3ca9ae1fe09cfc2ee8999acfc.jpg


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The edge of the case behind support where the arrow is had to ground a little get the bolt in at the top of the support. The bolt was very close to going in maybe a couple millimeters off and didn't want to force it and strip the threads. It was only tiny bit of grinding that I had to do. Just the variation in the case and bracket might allow some people to install it without any grinding
b7b1e9e3ca9ae1fe09cfc2ee8999acfc.jpg


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I just looked up the part# on amazon thanks for the pic it's. dry helpful
 
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