Well gents, a new year brings new problems. About a week or two ago I had to replace the battery on my car. I went into the mall and left my parking lights on for about 10 minutes and it killed the battery pretty bad...so I figured I'd just get a new one.
Since replacing the battery, I've noticed that when I let of the gas, as I get down to about 25 mph or so and the rpms drop, the car's lights would dim a little. I ignored that for about a week.
Now today, I'm driving home at like 11:30pm. I go to stop at a stop sign and the car about dies. I check the scanmaster volt reading and it drops down to about 11volts. I turn off the heater and the radio, and while cruising the voltage hops around from 12volts to 15 volts. Finally I pull into the devopment I live in and as my speed was dropping, the car dies. I stop the car, put it into park, and try to restart it. Nothing. I open the door, cabin light stays off. It does not appear that any voltage is getting to anything.
Now, my guess is alternator. Any tests I can run to see if this is the case? Or are there other tests I should run before running out and getting an alternator? I'm a little new to this whole home mechanic thing, so you're expertise is greatly appreciated.
first thing is to check all of the connections positive and negetive, at the batt, starter and the ground on the engine. it sounds like one or more is loose or bad.
Take the alt out and have it checked. Auto parts store or electrical shop can perform the test.
How do I check if a connection is "bad"?
Check out the acc'y drive belt first.
You recently replaced the battery...the obvious would be the battery cables. If the car has higher mileage on it, they are definitely suspect. You show the scanmaster voltage to be between 11 and 15 volts...alternator is working if that's the case. All the power goes dead meaning there is no connection between voltage and the rest of the car. Look to the battery cables or possibly a problem with the new battery. I've seen that happen before (low cell or internal break). Things to look for on the battery cable would be corrosion or bulging on the heavy cable caused by battery acid "leaching" up into the copper cable.
-John Spina
http://www.casperselectronics.com
Well, now that it is morning and light out, I went down to the end of the driveway where I left my car last night. I took a look at the connections to the battery, the bolts are pretty rusty. When I installed the new battery, the bolts were already rusty and round, so I used vice-grips to tighten them on. This morning, I tried tightening the negative cable to the battery and poof - the lights went on and the car would start. I'm thinking I need to replace the bolts. Sound right to anyone else? I think rust is more of an insulator than conductor.
Tom, If you can replace the cable bolts then fine.
I'm thinking they may be part of the cable
connector though. In any case, yes, rust is bad.
Clean, shiny metal, with a coating of No-Ox grease
or some other conductive corrosion inhibitor,
is always desired regarding battery connections.
(all electrical connections in the engine bay for
that matter)
...and they must be TIGHT.