is my alternator working?
07-05-13, 08:40 PM
#2
This is covered in the Second Gen FAQ in greater detail, but here's the gist of it. Hook up a multimeter to the battery terminals and look for the following:
Engine off: ~12.6v
Key in ON: ~12.6v
Engine Running: 13.5-15.0v
13.5 is the minimum necessary to recharge the battery. If it reads lower while the engine is running, the car is running off the battery, indicating that the alternator is failing or is not wired correctly. Above 15.0 is very bad and means the voltage regulator is shot or not connected. Do not attempt to drive the car when it reads above 15.0v, you WILL fry important things like the ECU.
S4 alternator issues are quite common and can be fixed permanently on the cheap too. Most swap to a FD alternator (first mod that I did), which is fine for a stock-ish car, possibly equipped with an E-fan. However, if you are using one of the thirstier fans like the 2-speed Taurus one, I would suggest going straight for the 130A Alternator out of a 3.8L Ford Taurus as I am using now. Either way will mean upgrading the output cable to 4awg
Another thing I'd like to mention is that sketchy battery terminals, such as the original ones
, can create starting/charging issues. This is why I highly recommend a pair of Marine Battery Terminals with the wing nuts on them. Brand doesn't really matter, Autozone or Walmart ones work just fine. Mine came from the bargain bin at Lowes for $1. The other reason why I recommend them is because if you are upgrading the alternator output cable, it would be VERY wise to de-loom the harness enough to remove the original one to prevent shorts. This will mean having 3 cables meet at the positive terminal: starter, alternator & fuse box. Kind of hard to stack cables on anything other than marine battery terminal...
Here is the correct wiring for both the FD and Taurus Alternators in a S4:
Engine off: ~12.6v
Key in ON: ~12.6v
Engine Running: 13.5-15.0v
13.5 is the minimum necessary to recharge the battery. If it reads lower while the engine is running, the car is running off the battery, indicating that the alternator is failing or is not wired correctly. Above 15.0 is very bad and means the voltage regulator is shot or not connected. Do not attempt to drive the car when it reads above 15.0v, you WILL fry important things like the ECU.
S4 alternator issues are quite common and can be fixed permanently on the cheap too. Most swap to a FD alternator (first mod that I did), which is fine for a stock-ish car, possibly equipped with an E-fan. However, if you are using one of the thirstier fans like the 2-speed Taurus one, I would suggest going straight for the 130A Alternator out of a 3.8L Ford Taurus as I am using now. Either way will mean upgrading the output cable to 4awg
Another thing I'd like to mention is that sketchy battery terminals, such as the original ones
, can create starting/charging issues. This is why I highly recommend a pair of Marine Battery Terminals with the wing nuts on them. Brand doesn't really matter, Autozone or Walmart ones work just fine. Mine came from the bargain bin at Lowes for $1. The other reason why I recommend them is because if you are upgrading the alternator output cable, it would be VERY wise to de-loom the harness enough to remove the original one to prevent shorts. This will mean having 3 cables meet at the positive terminal: starter, alternator & fuse box. Kind of hard to stack cables on anything other than marine battery terminal...Here is the correct wiring for both the FD and Taurus Alternators in a S4:
07-05-13, 10:30 PM
#5
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Professor Comet will be giving a quiz next tuesday on this subject.
Very well done and worth saving into the FAQ thread.
But I'm not sure that would be my definition of "gist".
But I'm not sure that would be my definition of "gist".This is covered in the Second Gen FAQ in greater detail, but here's the gist of it. Hook up a multimeter to the battery terminals and look for the following:
Engine off: ~12.6v
Key in ON: ~12.6v
Engine Running: 13.5-15.0v
13.5 is the minimum necessary to recharge the battery. If it reads lower while the engine is running, the car is running off the battery, indicating that the alternator is failing or is not wired correctly. Above 15.0 is very bad and means the voltage regulator is shot or not connected. Do not attempt to drive the car when it reads above 15.0v, you WILL fry important things like the ECU.
S4 alternator issues are quite common and can be fixed permanently on the cheap too. Most swap to a FD alternator (first mod that I did), which is fine for a stock-ish car, possibly equipped with an E-fan. However, if you are using one of the thirstier fans like the 2-speed Taurus one, I would suggest going straight for the 130A Alternator out of a 3.8L Ford Taurus as I am using now. Either way will mean upgrading the output cable to 4awg
Another thing I'd like to mention is that sketchy battery terminals, such as the original ones, can create starting/charging issues. This is why I highly recommend a pair of Marine Battery Terminals with the wing nuts on them. Brand doesn't really matter, Autozone or Walmart ones work just fine. Mine came from the bargain bin at Lowes for $1. The other reason why I recommend them is because if you are upgrading the alternator output cable, it would be VERY wise to de-loom the harness enough to remove the original one to prevent shorts. This will mean having 3 cables meet at the positive terminal: starter, alternator & fuse box. Kind of hard to stack cables on anything other than marine battery terminal...
Here is the correct wiring for both the FD and Taurus Alternators in a S4:
Engine off: ~12.6v
Key in ON: ~12.6v
Engine Running: 13.5-15.0v
13.5 is the minimum necessary to recharge the battery. If it reads lower while the engine is running, the car is running off the battery, indicating that the alternator is failing or is not wired correctly. Above 15.0 is very bad and means the voltage regulator is shot or not connected. Do not attempt to drive the car when it reads above 15.0v, you WILL fry important things like the ECU.
S4 alternator issues are quite common and can be fixed permanently on the cheap too. Most swap to a FD alternator (first mod that I did), which is fine for a stock-ish car, possibly equipped with an E-fan. However, if you are using one of the thirstier fans like the 2-speed Taurus one, I would suggest going straight for the 130A Alternator out of a 3.8L Ford Taurus as I am using now. Either way will mean upgrading the output cable to 4awg
Another thing I'd like to mention is that sketchy battery terminals, such as the original ones
, can create starting/charging issues. This is why I highly recommend a pair of Marine Battery Terminals with the wing nuts on them. Brand doesn't really matter, Autozone or Walmart ones work just fine. Mine came from the bargain bin at Lowes for $1. The other reason why I recommend them is because if you are upgrading the alternator output cable, it would be VERY wise to de-loom the harness enough to remove the original one to prevent shorts. This will mean having 3 cables meet at the positive terminal: starter, alternator & fuse box. Kind of hard to stack cables on anything other than marine battery terminal...Here is the correct wiring for both the FD and Taurus Alternators in a S4:
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