We have changed battery, alternator, still have a serious charging problem. Battery gets drained, is there something other than an alternator that can be checked?
I have had nearly exactly this problem in a different car. The starter was the culprit. It was worn down to a point where it was just threshold acceptable electrically and mechanically to turn and do its work. Yet it drained very high amperage during this work. If you have the time, remove the starter and disassemble it. Then cleant the copper commutator thoroughly using ScotchBrite pad, diesel fuel and strong hands.Then ensure the brushes are long enough and brush springs are ok, then clean brushes and holders with a stiff brush and fuel. Then blow dry with compressed air the run a bench test...clamp the starter down and apply a well-charged car battery and an ammeter. It should only draw about 5 to 10 amps steady after startup, but much heavier at startup under load...could be up to 500 amps depending on your bench test....difficult to apply loads here...main point is low current under no load.
A second possibility, other than a wire harness default, is the car's computer has gone bad...try a diagnostic code checker...
Ignition coil not powering right
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batterys are refurbed these days and sometimes an unlucky person can still get a dead cell battery several times even if the you bought brand new
i took mine back 4 times before i found a good one that kept its charge
dead cells dont show them selves very well on battery tests even though dead cell the tester would show good show dont think that there is something definatley wrong you could be in same ditch i was before with my batterys
alternator testers at some shops are not reliable enough i recommend a voltage tester to battery
Hello,
I am seeing a lot of mustangs are having battery draining issues and I wish to share some simple solutions found while working on a friends 03 GT 4.6ltr.
In a quiet area, key switched off, hood up, Listen carefully close to alternator. I heard a high pitched hissing/whistle sound at low volume, came from back of alternator. This sound was the voltage regulator/rectifier staying on when key is off due to faulty diodes inside the voltage regulator/rectifier circuit, can cause battery to go dead after car not ran in about 2-7 days.
After having the alternator tested free at a parts store, test showed alternator was good because the faulty diodes in the alternator did not show up on the test, the machine did not test for faulty drain back issues that were present.
Alternator on-car-fix:
There was battery voltage running at all times through the two-wire connector on back of alternator. Disconnect the battery first for safety and to reduce chance of short circuit. The yellow wire/with white stripe is hot while car is off so I traced this from the 2-wire connector on the alternator then closer towards driver side front fender. Next I cut the Yellow/White Stripe wire, spliced a good connection wire to it and ran it through a hole in the fire-wall to the fusebox(under dash), connected it to a 15a fuse that does not get used but has power when key is turned on but no power when key is off.
The purpose for re-routing the hot wire to the alternator, is to turn off the alternator charging circuit when the key is turned off so it may not run down the battery. I am seeing good results with this fix(or patch) so far. No More Parasitic Battery Drain!
Another fix can be to change the small pulley on the alternator to a larger pulley so the alternator does not spin too fast, putting too much energy through the diodes can cause a charging system to act a fool. So if you have charging issues and have an alternator changed, putting a larger pulley on can make sense turn into saved dollars(especially on high revving engines).
I hope this info helps to solve some draining battery and/or alternator issues.
for reading,
TyBorg1
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helpful hints, thanks for all the help.
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