Alternator problems
Alternator problems Recently having power issues with my car so now I'm learning all about this. When my car is cold the car runs fine and dash gauge is reading normal but when I street drive my car on the street for a while (30 mins+) the gauge starts to go down and hovers over the red on the dash. The other night when cruising around my fuel pump started to lose power via different whines from the pump and my headlights started to dim. Next day I took my alternator to parts store and it checked out good (cold) but then my buddy said when it's hot it could fail?
Power supply is a 8g wire from alternator to my firewall where my distribution block is for the entire car. I recently just got 1g welding wire to run back to battery so my cut-off switch works properly but I'm on the fence if I should buy a new 145 amp alternator or if mine is good?
Power supply is a 8g wire from alternator to my firewall where my distribution block is for the entire car. I recently just got 1g welding wire to run back to battery so my cut-off switch works properly but I'm on the fence if I should buy a new 145 amp alternator or if mine is good?
I had the same problem with an Autozone reman alternator. It would always test fine cold, but when hot voltage dropped. The fix was a new voltage regulator. I put a new set of brushes in at the same time since they are soldered to the regulator.
Your alternator is the life line of everything, you should always invest in a decent one. Is your grounds adequate enough? Your ground wire should always be large than your power wire.
Just putting this out there since we are talking wiring, don't ever use stereo grade wire it is CCA and even though it says 2 gauge it isn't the same as 2 gauge OFC wire.
Just putting this out there since we are talking wiring, don't ever use stereo grade wire it is CCA and even though it says 2 gauge it isn't the same as 2 gauge OFC wire.
You need to run an 4 awg wire off your alternator straight back to your battery. Or your cut off switch on the battery side.
This way it's charging your battery the whole time. And not back feeding it through the 1/0 wire. So to speak.
Also the way you have the alternator wired to the distribution block, will not kill the car by the cut off switch. You would kill power to the distribution block but the alternator would still keep the car running.
This way it would be properly wire and you might not need a new alternator. The way it's wired now maybe putting a strain on your battery and/or alternator.
This way it's charging your battery the whole time. And not back feeding it through the 1/0 wire. So to speak.
Also the way you have the alternator wired to the distribution block, will not kill the car by the cut off switch. You would kill power to the distribution block but the alternator would still keep the car running.
This way it would be properly wire and you might not need a new alternator. The way it's wired now maybe putting a strain on your battery and/or alternator.
Last edited by RENE'S RAGE; Oct 16, 2015 at 09:54 AM.
Swap in a new voltage regulator. I've been where you are and pulled my hair out trying to find the problem. I added bigger cables, cleaned and dielectric-greased all connections, and even fit a larger battery in the stock location. The voltage regulator was the root cause of the problem. Heat ages them over time. You can pick one up with new brushes from Rock Auto for ~$40. It's a pretty easy install too, just a little bit of soldering.
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Your alternator is the life line of everything, you should always invest in a decent one. Is your grounds adequate enough? Your ground wire should always be large than your power wire.
Just putting this out there since we are talking wiring, don't ever use stereo grade wire it is CCA and even though it says 2 gauge it isn't the same as 2 gauge OFC wire.
Just putting this out there since we are talking wiring, don't ever use stereo grade wire it is CCA and even though it says 2 gauge it isn't the same as 2 gauge OFC wire.
You need to run an 4 awg wire off your alternator straight back to your battery. Or your cut off switch on the battery side.
This way it's charging your battery the whole time. And not back feeding it through the 1/0 wire. So to speak.
Also the way you have the alternator wired to the distribution block, will not kill the car by the cut off switch. You would kill power to the distribution block but the alternator would still keep the car running.
This way it would be properly wire and you might not need a new alternator. The way it's wired now maybe putting a strain on your battery and/or alternator.
This way it's charging your battery the whole time. And not back feeding it through the 1/0 wire. So to speak.
Also the way you have the alternator wired to the distribution block, will not kill the car by the cut off switch. You would kill power to the distribution block but the alternator would still keep the car running.
This way it would be properly wire and you might not need a new alternator. The way it's wired now maybe putting a strain on your battery and/or alternator.
Swap in a new voltage regulator. I've been where you are and pulled my hair out trying to find the problem. I added bigger cables, cleaned and dielectric-greased all connections, and even fit a larger battery in the stock location. The voltage regulator was the root cause of the problem. Heat ages them over time. You can pick one up with new brushes from Rock Auto for ~$40. It's a pretty easy install too, just a little bit of soldering.
I have a 145 amp truck alternator now, just think my whole layout is too small.
It's the wiring. The stuff you used just can't get the job done. Once you get the good welding cable on for your main power, and get rid of the stereo junk wire you will likely be a lot better if not resolve your issues completely.
I would ground both heads to the frame rail just to be safe. Seems overkill, but I have never, never heard of a car that didn't run right because it was too well grounded.
I would also run a dedicated ground to the battery for the computer. Just keeps the noise down, stock pcm's aren't real touchy with it, but never hurts.
As for your cutoff switch, if you want to make sure it kills the car make sure the power for the fuel pump is on the opposite side of the master kill switch from the battery. This way when you hit that switch it kills the fuel pump, that is a guarantee that the car is going to die when you hit the switch.
I would ground both heads to the frame rail just to be safe. Seems overkill, but I have never, never heard of a car that didn't run right because it was too well grounded.
I would also run a dedicated ground to the battery for the computer. Just keeps the noise down, stock pcm's aren't real touchy with it, but never hurts.
As for your cutoff switch, if you want to make sure it kills the car make sure the power for the fuel pump is on the opposite side of the master kill switch from the battery. This way when you hit that switch it kills the fuel pump, that is a guarantee that the car is going to die when you hit the switch.
Good welding cable is the best choice and I run my ground back up to my block. The frame is not good grounding points. I do what JL ws-6 mentioned as I tie both heads together with grounds and back to the same location my batter ground connects to on the block.
Chassis grounds are good secondary grounds because you can't have to many grounds but they are not good enough as main grounds.
Chassis grounds are good secondary grounds because you can't have to many grounds but they are not good enough as main grounds.
Got the car running again tonight, seems to be better and fuel pump sounds quieter. However when my 2 fans kick on is when it drags my power down, headlights dim when they kick on. There huge fans and each is on its own relsy and wired totally on their own circuit. I had 30a fuses on each fan and it would pop them when they turned on so I had to put in 40a fuse and now there good but still pull lots of power. Higher amp alternator? I think I may pull the noise on one of the fans and just run 1 for now in the cooler temps, plus flowing 2200 cfm each, I think 1 will be fine for now.
Higher all alt. Probably your best bet. I'm sure the car runs cool with 2 of those fans but is it needed.... Can you get away with just one? May want to look around for a lower draw fan but the alt. doesn't sound like its up to be task
Exactly my thought of just running 1 fan. The pcm turns the fans on and I can literally watch the gauge drop when each fan turns on. I'm going to pull the fuse on 1 fan and just run 1. The car stays extremely cool so I'm sure it'll run on 1 fan with ease and the other I'll put on a toggle switch for the pit's or really hot stop n go traffic.
Way too much for anything less than a 200 amp alt I would guess.
I put a tiny radiator in my car with a remote meziere pump on it, has a fan and shroud on it.
Likely going to wire the car with a race wire setup (racepak's wiring setup) so I can program the fans to turn in/off, water pump to turn on/off, set it up so when nitrous is armed the fans all turn off until it's disarmed, etc. I dunno how the race wire and nlr1000 will interact yet but we will see.
You're overkill on the fans. I'd set one up to turn on/off like you do, 2nd probably set he temp so if it gets over 220 or somewhere it won't see this time of year or hardly ever to turn on and have it turn off at 200 or something so that it won't run much at all
I put a tiny radiator in my car with a remote meziere pump on it, has a fan and shroud on it.
Likely going to wire the car with a race wire setup (racepak's wiring setup) so I can program the fans to turn in/off, water pump to turn on/off, set it up so when nitrous is armed the fans all turn off until it's disarmed, etc. I dunno how the race wire and nlr1000 will interact yet but we will see.
You're overkill on the fans. I'd set one up to turn on/off like you do, 2nd probably set he temp so if it gets over 220 or somewhere it won't see this time of year or hardly ever to turn on and have it turn off at 200 or something so that it won't run much at all
I had a stock LT1 alternator which is around 140amp AFAIK, same setup as you with regards to electrical load and it did not keep up. Swapped in a 200amp aftermarket unit and no issues as of yet.
1/0 from starter to switch, 1/0 from alternator to battery, 1/0 alternator case to chassis, 1/0 battery ground to chassis, overkill is always easier than thinking.
1/0 from starter to switch, 1/0 from alternator to battery, 1/0 alternator case to chassis, 1/0 battery ground to chassis, overkill is always easier than thinking.