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Discussion Starter · #1 ·
My alternator was making a high pitch whine, I drove it a couple days with the A/C and radio off because I had no choice with work and it was only a 5 mile commute. When I am on the drive to the shop my car dies with the typical alternator signs...battery gauge goes limp, interior lights (radio clock, etc) go off, car surges and then dies. My wife gives me a jump, but it doesn't even make it 8 blocks before dead again, so I just call a tow truck because it is a busy roadway.

The alternator is find to be the culprit and is replaced. My car seems happy and drives fine going home. The next day it again starts up great and I make it through about 20 minutes of running errands then same exact death. This time however, a friend's dodge truck v8 can't even help charge me up. I can boost off, but within 10 seconds of removing the booster cables my car dies. We even tried leaving them on for 6-7 minutes the next time, same result.

I call the shop pissed off because it does not seem that they fully re-charged and then re-tested the battery once the new alternator was installed. They admitted the error and offered to pay to have it towed back and tested for free. We did that and ended up being a bad battery and they gave a discount on a new one for my being stranded during summer heat troubles.

Again, the car does great going home. Last night (around 3 hours later) I get in my car and the battery light comes on and the battery gauge starts to flutter although holding roughly in the middle. I shut it off and drove my wife's car to work.

The basic idea I get from a ton of internet browsing are these:
1. bad/corroded cabling
2. I got unlucky in the remanufactured alternator dice roll
3. Parasitic drain and I need to test each fuse individually

The shop used was unfortunately Pep Boys, pro-start is the alternator I believe, and the new battery is their most expensive line as well.

One big question I have is how do I check the cabling? It seems to disappear into engine oblivion and its all sheathed anyway. Is there some way to disconnect it and test both ends like you would in a house or internet/tv cabling?

Oh, and the terminals are both good, clamped tight, cleaned, and protectant treated sitting on the felt looking corrosion washers.

Any help would be appreciated, its not a good month financially, so as much as I can do myself would be ideal.
 

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well if pep boys did the job, i am sure they checked the condition of the cables. However a slight or bad ground contact anywhere on the engine will result in the problem your describing. I would look for any grounding leads to the frame/firewall areas. A bad ground seems the logical thing since pep boys did a retest on the alt.
 

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Discussion Starter · #3 ·
Sounds good, will pay careful attention to the ground and check to make sure everything is bolted down tight for it at all points. I am trying to share your optimism, but they assured me 2 days ago they re-tested the battery and then had to admit they did not. I pray it wasn't the same for the alternator after they installed a new battery.

If I buy a meter, can I simply test the current on both the battery and alternator myself like I would wires in a house by just touching them with the meter probes?
 

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you can go to auto zone or advanced and they can check your charging system free . Happened to think, have you noticed a loss of power on giving the car gas? Wondering if you dont have a fuel issue. A drop in pressure would cause the car to die down and once its a certain rpms will trigger the alt/ battery lights since there more demand for the charge than there is out put form the alt. worth checking into.
 

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Discussion Starter · #5 ·
Surprisingly I haven't had any acceleration issues. Even yesterday before it went into electrical nosedive, it was running very well in and out of traffic.

To its credit there, the car seemed to even fight like mad to stay alive surging when losing battery power. The jeep cherokee I had way back in high school just died instantly when it's alternator went out, whereas the mustang has to go engine kicking and fighting.
 

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Check the white fusible links in the main battery cable. These provide power to the alternator and likely have burned up after the battery was installed backwards.

Disconnect the small alternator conector. Test the voltage at the battery itself. Next test at the alternator B+. Should be the same.

If the fusible links have burned up, they are not normally servicible. Replace the whole cable.

Remember the alternator needs the battery to excite the field coil. They are a team.

No battery = no alternator.

The days of jump starting a car with a totally dead battery are over. If the battery is totally dead, when jumped it will run for a time but when the load increases (something turns on), the alternator will shut down.

There must be some small amount of juice left inside the battery to provide the initial "kick" to start the alternator. This is called excitation.

Since the battery is new, either the cables are bad, or there's a loose connection, a brake in the wires, the battery itself is bad.
 

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Discussion Starter · #7 ·
My plan tomorrow then is to buy a charger and power meter.

1. Pull the battery off and let it start charging
2. check the grounding cables with visual inspection
3. make sure other relevant wires are plugged in nice and snug (alt., starter, etc)
4. Check the white fusible links in the main battery cable
5. Check the grounding harness
6. test the battery voltage when it is fully charged
7. put the battery back in and test alternator at B+

...does this sound like a good initial attack?
Again, I appreciate the feedback and help!
 

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Discussion Starter · #9 ·
Ended up being yet another bad alternator. Will have to see if the next few days of driving shows that was the only issue.
 
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