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Unread 07-02-2014, 12:59 PM   #1
turkish6
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1982 CJ8 
 
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Alternator or Bad Electrical Repair?

This is long I apologize

Hey Everyone,

About 10 days ago I took my CJ to a local car electrician that specializes in American cars and has worked on a good amount of Jeeps in the past. He also came highly recommended by my local Jeep mechanic.

The PO had the ignition on the steering column disabled and replaced with one on the dash. I wanted to go back to the steering column so I purchased a new ignition switch and ignition cylinder. When we opened up the column we saw that the guts had been butchered. We found local used parts and he was able to successfully install everything and make everything work the way it should.

After I picked up the jeep from him I took it home and played around with it a bit and it started up beautifully every time. No issues at all. The jeep sat for about 7 days without running and when I went to start it, it again started right up without any issues. I made a quick run to the store and back (3 miles tops). When I got back I left it idling and I checked that my lights were working and my blinkers etc (weather was nice and I was just fooling around with it) Anyway, I turn everything off again etc. This morning (2 days after last start) I got in the Jeep and it was completely dead. No sound, no lights, nothing. I checked that all lights are turned off and everything was in fact off.

I checked that all battery, starter and alternator connections are secure. I hooked up jumper cables and she started right up. I drove it around for about 20 minutes on some back roads. Came back home, turned her off. I tried to start it again right after and it wouldn't turn over. Not enough juice.
It wasn't dead but just wouldn't turn over. I jumped it again and hooked up my multi-meter. With engine at idle I am getting a reading of about 12.67. Revving the engine up I got a max reading of 13.72.

I talked to my mechanic and he says it's the alternator. Normally I wouldn't doubt him but it's just strange I all of a sudden started having issues after some electrical work was done. Is there anyway the ignition switch was hooked up incorrectly cause the battery to drain? Is it just coincidence?

The battery was replaced 6 months ago.

Thank you for reading

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Unread 07-02-2014, 01:06 PM   #2
grasmo
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charge the battery, load test it, check alt. output w/o a load and then with a load. if all good, check for parasitic draw.
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Unread 07-02-2014, 01:11 PM   #3
Mike Romain
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Could your alternator pulley be slipping? You are showing low volts. I test them by taking a cold off engine and seeing if I can hand slip the pulley. If I can the belt needs tightening or replacing.

A bad connection can also cause that. I put the meter probes on the running engine's battery posts and read. I usually turn on the lights and fan for load. I then go to the alternator case with the neg leaving the pos probe on the battery plus. If the volts jump up, I walk the probe back. To the block, then the battery cable clamp to the block, then the clamp on the battery. If the volts change, I have found the bad connection. Same for the positive probe. From the post, to the clamp, then to the bolt on the fender solenoid.

I also take a read from the red wire on the back of the alternator to the alternator case.

It is amazing how often the alternator bracket has a bad connection. When that happens I add a dedicated ground wire.
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Unread 07-02-2014, 01:29 PM   #4
zillla
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Better yet test it yourself. Get a good DC voltmeter and put it on the battery while the engine is running. You should see ~ 14 volts. If less, Like 12 or less then your alt is tits. With the engine off you should see 11-12 volts across the battery
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Unread 07-02-2014, 11:23 PM   #5
BagusJeep
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Quote:
Originally Posted by turkish6 View Post
This is long I apologize

I checked that all battery, starter and alternator connections are secure. I hooked up jumper cables and she started right up. I drove it around for about 20 minutes on some back roads. Came back home, turned her off. I tried to start it again right after and it wouldn't turn over. Not enough juice.
It wasn't dead but just wouldn't turn over. I jumped it again and hooked up my multi-meter. With engine at idle I am getting a reading of about 12.67. Revving the engine up I got a max reading of 13.72.

I talked to my mechanic and he says it's the alternator. Normally I wouldn't doubt him but it's just strange I all of a sudden started having issues after some electrical work was done. Is there anyway the ignition switch was hooked up incorrectly cause the battery to drain? Is it just coincidence?

The battery was replaced 6 months ago.

Thank you for reading
Where are you taking the readings?

If this is at the battery you should see about 12V without the engine on and 13.5 to 13.9V with the engine on and no electrical equipment on. A properly working and wired alternator will give a consistent output at a fast idle and above. It is acceptable that it will drop slightly at a low idle but I would still expect to see 13V i.e. the battery is charging.

It may be a loose belt, may even be a "bad" alternator but it may also be the wiring. It is also possibly a battery fault.

Have you workedout if you have a 1, 2 or 3 wire alternator? This refers to the number of wires you have connected to the back.

Wire 1
There is always a large wire (could be red or brown) connected to the large lug that may be marked BAT. This is the output and it goes to the solenoid, connects with the main battery cable and hence feeds juice to the battery to charge it.

As stated above you should be able to connect one end of your voltmeter to the battery negative post and with the other go from the BAT post to the solenoid to the battery positive and get about the same reading everywhere. If you do not you have a dirty connection, bad wire etc.

You can also test the circuit (current flows round a circuit that also includes the engine block) the other way by connecting to the battery postive post and then going from the alternator casing, to the bracket, to the engine block, to the earth strap and to the battery negative post. You should have the same voltage at all locations. If you do not you may have a ground problem.

Wire 2

On a 2 or 3 wire setup you will have an ignition or FLD post. The ignition circuit tells the alternator to start working by energising the field. Take off the wire and check you have battery voltage in Run. When the engine is off check the post has no voltage, sometimes they leak power back into the ignition and drains the battery. If so a $2 diode can stop the back flow.

Wire 3

The third wire on a 3 wire setup is the sense wire. This is sensing voltage at a point in your vehicle's harness and adjusting the alternator output accordingly. It should be connected at the solenoid.
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Unread 07-03-2014, 02:15 AM   #6
turkish6
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I appreciate everyones replies. I will hopefully run the tests recommended tonight after work and report back.

My connections were all solid but I will take another look to be sure.

My readings were taken at the battery posts.
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Unread 07-03-2014, 02:41 AM   #7
grasmo
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Quote:
Originally Posted by turkish6 View Post
I appreciate everyones replies. I will hopefully run the tests recommended tonight after work and report back.

My connections were all solid but I will take another look to be sure.

My readings were taken at the battery posts.
also make sure the battery case is clean. check voltage on the plastic case with your meter.
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Unread 07-03-2014, 04:47 AM   #8
turkish6
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Quote:
Originally Posted by grasmo
also make sure the battery case is clean. check voltage on the plastic case with your meter.
How do I check the case?
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Unread 07-03-2014, 04:51 AM   #9
grasmo
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Originally Posted by turkish6 View Post
How do I check the case?
touch the case with both probes, preferably on the top, and measure voltage. should be 0v. if the top is dirty or leaking it will show voltage and could be your drain.
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Unread 07-03-2014, 06:51 AM   #10
Mike Romain
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Quote:
Originally Posted by grasmo View Post

touch the case with both probes, preferably on the top, and measure voltage. should be 0v. if the top is dirty or leaking it will show voltage and could be your drain.
Man it would have to be seriously gungy to do that. You can get a drain over time that way to a concrete floor on well used batteries, but it isn't a fast drain. Over months in storage. ( and before someone jumps me for that 'myth', have tested it with banks of electric boat motor batteries, it is real)
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86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
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Unread 07-03-2014, 07:23 AM   #11
grasmo
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Quote:
Originally Posted by Mike Romain View Post
Man it would have to be seriously gungy to do that. You can get a drain over time that way to a concrete floor on well used batteries, but it isn't a fast drain. Over months in storage. ( and before someone jumps me for that 'myth', have tested it with banks of electric boat motor batteries, it is real)
actually is doesn't take much dirt or fluid to get a 12v reading. usually it's much lower but anyway.....the concrete deal just slows the electrolyte. it doesn't 'drain' the battery like dirt or fluid does by creating an electrical circuit. you can take that same battery, get it up off the concrete and let it sit for a while and it will return to its normal state.
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Unread 07-03-2014, 08:37 AM   #12
LumpyGrits
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OP-try another known good battery.
If the batt still draws down-Look for parasitic drain. Pull the wiring to the alt and see what happens.
What accessories do you have wired into your electric system?
LG
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Unread 07-04-2014, 12:01 AM   #13
turkish6
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I didn't have a chance to take readings last night but this morning it started up. It was more of a cold weather type start (even though it's quite warm outside). It sat close to 30 hours after driving it for about 20 minutes.

Still need to look into this because my initial readings were low.

I can assure you that the battery case is not the issue. It's very clean.
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Unread 07-08-2014, 10:15 AM   #14
zillla
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Sounds like a battery issue to me..
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Unread 07-08-2014, 10:38 AM   #15
delirious1
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My CJ ingnition cylinder will allow for voltage to the volt meter if I don't turn it just right. Even with key out. I've got to replace it but make sure the system isn't still on after you remove the key. I'm hoping the cylinder is the issue. I just am not sure how to rekey the cylinder and doors.
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