fd alernator blowing stock main fuse
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fd alernator blowing stock main fuse
okay so i was hammering down the interstate doing some fuel tuning because i just got a new turbo installed today. at 7k rpms the car dies and i roll to a stop in the emergency lane. right before this though i noticed on my stock voltometer that i was at 15 volts. well i get out and pop the hood and my main fuse is blown. it's an 80 amp. from what i hear the fd uses a 100 main fuse. do i need to get a 100 main fuse for my setup or is there a larger problem i need to be looking for?
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Originally Posted by J-Rat
How is it wired?
When I start my car I have to rev the engine over 3000 miles to activate the alternator.
Today I hooked up the L terminal to the W/B wire and now when I start my car the alternator is already active. I've been driving around today tuning fuel because I installed a new turbo. But now I seem to be blowing my 80 amp main fuses. I blew one tonight while tuning fuel (7k rpms in boost, yikes!). luckily ih ad a spare in my car so i replaced then, then when driving 80mphs on the way home the main fuse blew again. so i either need a higher amperage fuse or I'm guessing I need to unhook my L terminal.
I do notice that my voltage is alot higher than it usually is during night driving. it's usually around 14.2 (haltech verified) but now it's at 15volts. my guess it during the higher rpms the alternator is producing even more amperage thus blowing the main fuse. But it's weird that it didn't start doing that tonight. But earlier today i wasn't hammering on it or going over a certain rpms so I can't really be sure. I'm going to ground my car for awhile while I figure this out. IF anyone has any insight, let me know.
#4
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You don't need to upgrade the MAIN fuse when you upgrade the alternator, and nor should you. The alternator only provides whatever current the car's system are drawing. If you've added high current electrical items like amps and e-fans, they should not be going through any of the stock fuses, so upgrading them is unnecesary (and potentially damaging). Nor should you disconnect anything from the alternator.
If you're popping a fuse, look for shorts. If the voltage is higher than normal, there's most likely a problem with the voltage regulator.
If you're popping a fuse, look for shorts. If the voltage is higher than normal, there's most likely a problem with the voltage regulator.
#6
Originally Posted by RotaMan99
Wouldn't adding a 100amp fuse where the 80amp fuse is, reduce the resistance and possibly allow current through easier and charge the batt easier?
ohms(impedance) has to do with resistance not amps.
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Originally Posted by RotaMan99
Wouldn't adding a 100amp fuse where the 80amp fuse is, reduce the resistance and possibly allow current through easier and charge the batt easier?
I'm no electrician..... but. it sounds like maybe you hooked the FD alt up wrong. It uses the same S, L, and + functions as any other alt. As long as you mapped those correctly from the FD plug to the FC harness, there should be no problem.
EDIT: Another note... The S5 FC's use a 100A main fuse as well, but are only sporting an 80A alternator. Isn't the FD one 100 or 105 or something? Not that it has anything to do with the problem... just curious.
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#8
I wish I was driving!
Originally Posted by jonesfromindia
ohms(impedance) has to do with resistance not amps.
When using an ohmeter, you can easily find a load's resistance. In an AC RLC circuit, however, the measured voltage and the measured current won't follow Ohm's law V=IR, like it does with a DC circuit. The measured current will always be lower than the calculated current. In AC circuits, the correct formula to use is V=IZ. Z can easily be calculated by the equation Z = [(XL - XC)^2 + R^2]^1/2.
More than anyone ever wanted to know about resistance.
Fuses do have resistance. Larger fuses always have less resistance than smaller fuses. However, the amount of resistance relative to the total system is always completely negligible. Its purely a theoretical argument. There is no measurable voltage drop across any working automotive fuse, and therefor, no considerable resistance. While upgrading to a larger fuse would give less resistance, we are talking a difference of micro-ohms. Completely moot to discuss.
If you are popping the 80 Amp fuse, you are definitely doing so through an electrical short somewhere in the car. Look towards any unfused aftermarket wiring you have, check for melted wire insulation in that circuit.
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I found the problem. I had everything wired correctly. The b terminal on the alternator was arcing to the intercooler causing it to short out. Sorry, newb move. Everything is working perfectly and I'm still sporting an 80amp fuse, np.
#11
I wish I was driving!
Originally Posted by micaheli
^^ OH.... Mr "Big Words" scathcart thinks he's SOOOOO coool....
Originally Posted by idsigloo
I found the problem. I had everything wired correctly. The b terminal on the alternator was arcing to the intercooler causing it to short out. Sorry, newb move. Everything is working perfectly and I'm still sporting an 80amp fuse, np.
Alternator belt too long?
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Originally Posted by scathcart
I wouldn't exactly call the nerdish quoting of first year eng courses "cool". If anything, its exactly the opposite. It was just a little post for anyone who wanted to know about the subject.
Good to hear. Thanks for posting this for future searches.
Alternator belt too long?
Good to hear. Thanks for posting this for future searches.
Alternator belt too long?
Besides, I did give you the
#13
I wish I was driving!
Originally Posted by micaheli
Yeah, I know... It was a joke.... do I need to wrap everything in <sarcasm> quotes?
Besides, I did give you the
Besides, I did give you the
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Originally Posted by idsigloo
I found the problem. I had everything wired correctly. The b terminal on the alternator was arcing to the intercooler causing it to short out. Sorry, newb move. Everything is working perfectly and I'm still sporting an 80amp fuse, np.
#18
Originally Posted by idsigloo
I found the problem. I had everything wired correctly. The b terminal on the alternator was arcing to the intercooler causing it to short out. Sorry, newb move. Everything is working perfectly and I'm still sporting an 80amp fuse, np.
but i am pretty sure my alternator is going to be a constant source of problems so yeh heh.
was the 3K+ rpm thing the same problem? or did you fix that by tightening the pulley system so the alternator was actually working 100%? some guy in another recent post is having that same problem i believe he has some kind of aftermarket fan on that changed the belt system
and actually, on that note... reading the mechanics manual on how to tune the belts... wtf..?!? has anyone actually done the red marker thing w/ degree angles or whatever it says. coz im pretty sure my belts are far from where they're supposed to be
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Originally Posted by so-mars
how'd you fix that? i'm assuming shielding? tape or something? i'm total noob.
but i am pretty sure my alternator is going to be a constant source of problems so yeh heh.
was the 3K+ rpm thing the same problem? or did you fix that by tightening the pulley system so the alternator was actually working 100%? some guy in another recent post is having that same problem i believe he has some kind of aftermarket fan on that changed the belt system
and actually, on that note... reading the mechanics manual on how to tune the belts... wtf..?!? has anyone actually done the red marker thing w/ degree angles or whatever it says. coz im pretty sure my belts are far from where they're supposed to be
but i am pretty sure my alternator is going to be a constant source of problems so yeh heh.
was the 3K+ rpm thing the same problem? or did you fix that by tightening the pulley system so the alternator was actually working 100%? some guy in another recent post is having that same problem i believe he has some kind of aftermarket fan on that changed the belt system
and actually, on that note... reading the mechanics manual on how to tune the belts... wtf..?!? has anyone actually done the red marker thing w/ degree angles or whatever it says. coz im pretty sure my belts are far from where they're supposed to be
To solve the arcing problem I put the boot over the b terminal tongue ring and electrical taped it. Then I put a few layers of duct tape on the intercooler where it was arcing for added protection. I haven't had any problems since.
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Fuses do have resistance. Larger fuses always have less resistance than smaller fuses. However, the amount of resistance relative to the total system is always completely negligible. Its purely a theoretical argument. There is no measurable voltage drop across any working automotive fuse, and therefor, no considerable resistance. While upgrading to a larger fuse would give less resistance, we are talking a difference of micro-ohms. Completely moot to discuss.
Thanks again.
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