p1637 and voltage surge.
Thread Starter
Staging Lane
Joined: Oct 2010
Posts: 70
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p1637 and voltage surge. Ok I just did the motor swap on my can and now im getting the p1637 code and my all my lights surge. I gets faster when you give it more throttle. And when i am driving and im around 1500 to 2000 rpm i get a voltage reading in the high 15s and if i give it my gas to around 3000 rpm it drops way down to around 10.2v.
What the hell could this be?
What the hell could this be?
where did you have the alternator checked? depending where, they usually have no clue what they're doing. but since the alternator does output, it's very unlikely there's a problem with the alternator. When it is the alternator, it does not output.
only way to get high voltage is for higher field current in the alternator, which is controlled by the alternator voltage regulator, and the regulator knows how to regulate the field current by the voltage sensing wire that connects into the + side of the wiring system, usually close or as close as possible to battery + post. If this connection is crappy, it sees a lower voltage and thinks there's a load on the system so it increases alternator field current so the alt. outputs higher voltage, and it tries to maintain a 13.5-14 voltage. The other way the regulator can get fooled is by bad grounds, that also causes the regulator to see a lower system voltage and causes it to make the alt. output higher voltage. So check all wiring and connections on the voltage sensing wire coming out of the 3 or 4 or 5 wire connector out the back of the alternator- many times this connector is bad and causes the alternator not to charge but in your case it's most likely the sense wire. Otherwise you have a bad voltage regulator- which should have showed up during the alternator test but they can be like starters... don't work on the car but work when you get them tested.
only way to get high voltage is for higher field current in the alternator, which is controlled by the alternator voltage regulator, and the regulator knows how to regulate the field current by the voltage sensing wire that connects into the + side of the wiring system, usually close or as close as possible to battery + post. If this connection is crappy, it sees a lower voltage and thinks there's a load on the system so it increases alternator field current so the alt. outputs higher voltage, and it tries to maintain a 13.5-14 voltage. The other way the regulator can get fooled is by bad grounds, that also causes the regulator to see a lower system voltage and causes it to make the alt. output higher voltage. So check all wiring and connections on the voltage sensing wire coming out of the 3 or 4 or 5 wire connector out the back of the alternator- many times this connector is bad and causes the alternator not to charge but in your case it's most likely the sense wire. Otherwise you have a bad voltage regulator- which should have showed up during the alternator test but they can be like starters... don't work on the car but work when you get them tested.
