CHADsterss

Hey guys, last Friday night on my way home from the local car meets I noticed my voltage gauge on the dash was riding on the orange. So I rush home trying to make it there before my car completely died, as I finally turn into my driveway my car starts sputtering and check gauges light, service vehicle light and ABS INOP lights are all on and it finally died (gauge showed 8v). That night I put my battery on a trickle charger because it had completely died(the battery was bought last year 10/12) The next day I replace the alternator with a new one from orielly's because the other one I had bought a year ago had lifetime warrenty. I was sure to have the bench test to make sure it works, it passed, I also bought and replaced the excitor wire and plug that goes into the top of the alternator.

So after all of this, when I first start my car it charges normally?(13v+ on the dash) then maybe after 5-10 min later down the road the needle starts slowly going down under 13v to where the point its resting just on where the orange hash part of the gauge begins maybe 11-12v. Now I just checked my battery with a multimeter and I got 12.85v with the car off and 12.3-12.5v with it running. I also tested where the positive cable meets the fuse boxes with the same results.

I'm just stumped to what the issue could be? a bad gauge? bad NEW alternator that tested good? or a bad battery even though its only a year old? I also have a hot wire kit for my fuel pump AND a very small system(10"sub with a 200watt amp) hooked up to the positive battery post at the fuse box but I've never had this issue before.

any help is appreciated.

02BlkZ28

Junk that alternator & go buy a aftermarket one that has more amps. I have a similar problem. My stock one i had that came with the car worked fine. But when it went out i bought a new one from napa & when i get on it at wide open throttle the gauge drops to about 10 or 11 volts. & from what i can find researching on here... They are junk. So im gonna buy a high out put one. I read a thread today that people are putting the 145amp alternator out of a 2003 pickup to fix the problem.

arock24

iTrader: (4)

The truck alternator is a popular swap but I personally didn't want to modify anything so I went to ws6store.com and picked up their Powermaster 150amp unit. Comparable price and excellent quality, I haven't had a problem since.

CHADsterss

Thanks for the responses guys, so y'all think if I upgrade to one of the 03 truck(145a) alternators it'll fix my problem? I was looking into doing it.

02BlkZ28

I would buy a aftermarket 145amp. The truck alternator you gotta make that top pig tail plug in longer. & you lose the back bracket for the alternator. & you might look into replacing your ground strap wire on the drivers side with a thicker ground wire. Just alil added security.

CHADsterss

I've already replaced the harness so it's extended quite a bit. Plus I have a LQ in my car so I already don't use the rear bracket lol looks like it'll be a pretty direct swap. Thanks for the advice, hopefully this fixes my problem.

MTN_Z

iTrader: (7)

You might want to check the exciter wire. It might be damaged. It sounds like you are having similar issues to what I was dealing with. The wire had pulled out of the back of the plug and it wouldn't charge.

CHADsterss

That's what I was talking about, on the last alternator I pulled out I was in a hurry to get to the parts store before it closed and I accidentally ripped it out lol. But I replaced it with a new one.

Blackpanther99

iTrader: (8)

You should go post this on the HPT forums. Youll get some badass help Chad.

LilJayV10

iTrader: (39)

Did you check the exciter wire when it's not charging? Did you check for a voltage drop at the big wire on the back of the alternator? Also see how many ohms you are getting from the negative post to the the block.

It sounds like something is breaking down after the car gets hot.

LilJayV10

iTrader: (39)

How did you splice in the new pig tail? Butt connector, solder?

It should be pretty easy to diag this I would think. I get most of the obscure wiring issue at work.

FWIW this is how I go about diag for an alternator issue. This needs to be done when the problem is present.

Check all connections, battery terminals, distribution blocks, etc
Check battery voltage
Check for battery voltage on the big wire on the alternator, it should be the same as B+, if it's not there's excessive resistance in the wire from the battery to the alternator, this can be from corrosion, a broken wire or partially broken wire or bad connector.
Check for B+ on the exciter wire on the alt. If there is none check to see if you are getting B+ at the PCM connector. It will be the red connector at the PCM, pin 15, red wire.

Check the resistance on the ground side, start from the the negative post to the ground distribution block and several different places on the block. I fixed a heater blend door on a Taurus a couple months ago by cleaning the ground wire going to the block. I wouldn't have believed it myself if I didn't do it.

I hope this helps some.

J

JakeFusion

iTrader: (7)

I was thinking Exciter wire. I had the same problem. I ended up resoldering the wire and the stock alternator is good to go now.

I had picked up a Powerbastards Alternator, but all it did was squeal like *** from the load of trying to produce 220A.

Strokedcamaroz28

check power wires and connections ihad this problem and it was a bad connection and a bad wire coming in and out of contact with the plastic clip

Paul Bell

iTrader: (9)

Yes, the advice for the 140 amp truck alternator is good but you need to confirm what caused your problem.

Alternator went bad and the replacement from Orielly's was bad

OR

The exciter wire was bad and you got a replacement with the incorrect pin location

OR

There's an open in the wiring harness from the PCM to the exciter plug.

CHADsterss

Thanks for all the help and replies, I just spliced it together for with a butt connector because I do not have a soldering iron. I'm guessing maybe the using the butt connector could be causing it to not work correctly(I don't understand why it would, maybe someone can clarify)? How exactly should I go about testing the excitor wire and the wire on the back of the alt? I have access to a multimeter and test light. Would I just uses the same 20v setting I used to check the battery?

CHADsterss

Thats what it seems like, the first few minutes of driving it charges just fine but a little bit later it slowly starts to dive off. I have also noticed the gauge has been quite erratic lately, for example, last friday on my way home I was at a red light and the gauge on the dash was reading around 10 volts then a few minutes later and it went back up out of the orange and went up to mayhemaybe 11.5-12ish volts

CHADsterss

bump!

danieloneil01

You can buy a solder gun for about 10 bucks. I would to ditch any spliced wire connectors/connections.

Old Geezer

iTrader: (3)

Try some voltage drop tests........All continuity test tell you is, that not all the wire strands are broken.

joecar

+1 ^ what he said.

CHAD:

voltage drop test will quickly reveal high resistance across a connection or a ground;

for example, the voltage drop on the battery-engine ground cable should be less than 0.3V.