electrical problem: voltage drop
06-12-2010, 05:20 PM
#21
If your getting good volts out of the alternator and a low voltage somewhere else then you are either drawing a whole bunch of current or you have a bad connection.
I don't think the alternator is your problem. If anything your wiring problems are killing the alternators.
Electrical problems are not fun but it comes with having an old car.
I don't think the alternator is your problem. If anything your wiring problems are killing the alternators.
Electrical problems are not fun but it comes with having an old car.
06-12-2010, 05:30 PM
#22
the cars entire electrical system is a new painless 18 circuit harness. everything worked fine with the old 355 i had in the car with a swap meet chrome 1 wire alternator. I just verified... i have a youtube video of the old SBC running and im getting 14.5V on the same gauge. all that is different is the 12V exciter wire i have running to the new LS1 alternator. The same heavy gauge wire is used. I literally took out the SBC and dropped in the LS1.
here is a pic of where i have the light bulb and 12V signal going to the alternator. is this correct?
when i key over the ignition the light bulb lights up then shuts off once the car is running.
should i add a 5v regulator? i hear that is all that is needed to make the regulator kick in. think my 12V signal is burning the regulator out?
here is a pic of where i have the light bulb and 12V signal going to the alternator. is this correct?
when i key over the ignition the light bulb lights up then shuts off once the car is running.
should i add a 5v regulator? i hear that is all that is needed to make the regulator kick in. think my 12V signal is burning the regulator out?
Last edited by DCx; 06-12-2010 at 05:50 PM.
06-12-2010, 09:44 PM
#23
Your headlights and dash aren't part of the Painless harness are they? My recollection of Painless is that they just deal w/ the engine...chassis is your problem.
06-13-2010, 02:09 AM
#24
the painless harness covers everything, steering column, wiper motor, headlight, tail lights, gauges, engine... gotta remember im not FI. Im running a carbed setup, thus no PCM for my alternator. my car was rewired with an 18 circuit painless muscle car harness.
I just think its odd that I didnt have any of these problems with my old SBC. Im using the same optima red top battery as well.
When we first fired the LS1 i only had the wire attached to the back of the alternator thinking it worked like a single wire unit. Battery eventually died because it wasnt charging. Added the light bulb in line to the plug ontop of the alternator and got it to sustain life.
Only other reason i can see my headlights drawing voltage is because they need relays. My electric fans dont mess with the voltage at all because i have them and my fuel pump all running through 40 amp relays. The painless harness didnt supply any relays i had to add them myself.
I just charged my battery some. Im getting 12.8 at the battery now as opposed to the 12.4 it was reading earlier.
i wish there was a way to cram an old style alternator in the LS1 bracket to test this out.
I just think its odd that I didnt have any of these problems with my old SBC. Im using the same optima red top battery as well.
When we first fired the LS1 i only had the wire attached to the back of the alternator thinking it worked like a single wire unit. Battery eventually died because it wasnt charging. Added the light bulb in line to the plug ontop of the alternator and got it to sustain life.
Only other reason i can see my headlights drawing voltage is because they need relays. My electric fans dont mess with the voltage at all because i have them and my fuel pump all running through 40 amp relays. The painless harness didnt supply any relays i had to add them myself.
I just charged my battery some. Im getting 12.8 at the battery now as opposed to the 12.4 it was reading earlier.
i wish there was a way to cram an old style alternator in the LS1 bracket to test this out.
06-13-2010, 07:58 AM
#25
06-13-2010, 12:29 PM
#26
yeah i hear truck alternators will bolt in place of the unique F body units without the back bracket installed. problem is, its still a CS style alternator.
http://www.novaresource.org/alternator.htm
found this link off the net about an SI to CS alternator swap. It gives info on the amount of resistance the L terminal on the alternator needs to see.
http://www.novaresource.org/alternator.htm
found this link off the net about an SI to CS alternator swap. It gives info on the amount of resistance the L terminal on the alternator needs to see.
The "L" wire that energizes the alternator needs some resistance (35 ohms or more) in it otherwise it will cause the alternator to fail. If you have a warning light in the dash then that bulb serves as the needed resistance and you should use the non-resistor adapter. If you don't have that bulb or have less than 35 ohms resistance in the "L" wire then you will need the adapter with resistance built in. If the "L" wire has more than 350 ohms then there is a problem with that wire and it will need to be fixed.
06-13-2010, 05:55 PM
#27
im not getting much further. i tried wiring in a 470ohm resister in place of my light bulb and it did nothing. threw the bulb back in and it works some what.
i pulled the autometer voltage gauge out of the dash to test the voltage going into it. I am loosing 1 volt through the fuse block some how. my battery will read a whole volt higher than the gauge will display, also the power wire leading to the back of the gauge reads lower than a 12v source in the engine bay.
also after having my alternator tested at the local autozone i reinstalled it and now am experiencing voltage drops when i rev the engine above 3000 rpm.
since i have the light bulb which offers resistance wired to the B or L terminal (same thing according to what thread you are reading) i am going to hook a keyed 12v wire to the C or F terminal and see if that works out.
gotta pull the dash as well and track down my in car voltage issues.
i pulled the autometer voltage gauge out of the dash to test the voltage going into it. I am loosing 1 volt through the fuse block some how. my battery will read a whole volt higher than the gauge will display, also the power wire leading to the back of the gauge reads lower than a 12v source in the engine bay.
also after having my alternator tested at the local autozone i reinstalled it and now am experiencing voltage drops when i rev the engine above 3000 rpm.
since i have the light bulb which offers resistance wired to the B or L terminal (same thing according to what thread you are reading) i am going to hook a keyed 12v wire to the C or F terminal and see if that works out.
gotta pull the dash as well and track down my in car voltage issues.
06-13-2010, 08:19 PM
#28
06-13-2010, 10:19 PM
#29
06-14-2010, 02:00 AM
#30
Not sure I'm following you...are CS style alternators a problem for your vehicle?
06-14-2010, 04:03 PM
#31
its all fixed and working now!
i ended up exchanging the alternator that was giving me a partial charge for a new one. I wired it up the same way with a light bulb in series to the L terminal and i now get a constant 14V throughout the entire system!
battery yields 14.3
alternator lead 14.3
fuse panel 14.3
volt gauge displays 14V
lead to the volt gauge yields 14V
i also sanded the contact points on the alternator bracket they had a tiny bit of black paint on them. I wonder if it also helps that this alternator has a standard pulley on it now as opposed to the ASP overdrive unit i tried out.
also the alternator withstands high revs. i held the engine at 5000 rpm for a few seconds and it still held 14V.
the headlights still draw power though. looks like i will add relays and see if that helps any.
i ended up exchanging the alternator that was giving me a partial charge for a new one. I wired it up the same way with a light bulb in series to the L terminal and i now get a constant 14V throughout the entire system!
battery yields 14.3
alternator lead 14.3
fuse panel 14.3
volt gauge displays 14V
lead to the volt gauge yields 14V
i also sanded the contact points on the alternator bracket they had a tiny bit of black paint on them. I wonder if it also helps that this alternator has a standard pulley on it now as opposed to the ASP overdrive unit i tried out.
also the alternator withstands high revs. i held the engine at 5000 rpm for a few seconds and it still held 14V.
the headlights still draw power though. looks like i will add relays and see if that helps any.
06-14-2010, 10:33 PM
#32
Congrats! With all these CS130 failures lately, including my rebuilt one last year, I'm starting to theorize that the Chinese-made rectifiers just aren't very robust.
My nearly 1 year-old NAPA rebuild died on a road course after three ~45-minute sessions of hard driving. I entered the main straight about 15 minutes into my fourth session, checked the gauges as usual, and noticed the volt gauge was below the 13 mark. I upshifted to 5th and brought the revs down, babied in back to the pits, still reading below 13. Borrowed a Fluke meter, batt showed 11.4 volts while idling. No spare alt to be found, but the volts were holding steady at 11.4V. I drove it home w/ no stereo or other current draws other than the powertrain, parked it and checked again...11.4V. The alt was putting out, but was missing one rectifier bridge.
I bought a brand new Delco alt and installed it, put the NAPA rebuild in my pit box as a spare. Will find out how it works in July when it's off to NJMP for a track day.
Good luck w/ yours!
My nearly 1 year-old NAPA rebuild died on a road course after three ~45-minute sessions of hard driving. I entered the main straight about 15 minutes into my fourth session, checked the gauges as usual, and noticed the volt gauge was below the 13 mark. I upshifted to 5th and brought the revs down, babied in back to the pits, still reading below 13. Borrowed a Fluke meter, batt showed 11.4 volts while idling. No spare alt to be found, but the volts were holding steady at 11.4V. I drove it home w/ no stereo or other current draws other than the powertrain, parked it and checked again...11.4V. The alt was putting out, but was missing one rectifier bridge.
I bought a brand new Delco alt and installed it, put the NAPA rebuild in my pit box as a spare. Will find out how it works in July when it's off to NJMP for a track day.
Good luck w/ yours!
08-20-2010, 04:15 PM
#33
i think that alternator was short lived. i started the car the other day and barely got 13v on the gauge again =(
i was surfing the net for more CS130d info when i came across an alternator shop that is local to me!
http://www.qualitypowerauto.com/
i called the guy and he told me my regulator was running wild with the way i had it wired with just the lamp in line to the L terminal. he told me i should run a wire from the S terminal to the post on the back of the alternator. this is the sense wire and will let my alternator know what the battery voltage is and when to regulate. he sells this pre made harness for this purpose. his has a diode wired inline so no idiot light is needed.
im going to give this a try with a fresh alternator and see if it works. if not im going to have him convert an F body alternator into a 1 wire self regulating style and call it quits.
i was surfing the net for more CS130d info when i came across an alternator shop that is local to me!
http://www.qualitypowerauto.com/
i called the guy and he told me my regulator was running wild with the way i had it wired with just the lamp in line to the L terminal. he told me i should run a wire from the S terminal to the post on the back of the alternator. this is the sense wire and will let my alternator know what the battery voltage is and when to regulate. he sells this pre made harness for this purpose. his has a diode wired inline so no idiot light is needed.
im going to give this a try with a fresh alternator and see if it works. if not im going to have him convert an F body alternator into a 1 wire self regulating style and call it quits.
08-20-2010, 05:54 PM
#35
08-31-2010, 11:28 PM
#37
i had a local alternator shop install a self exciting regulator in my existing alternator. only cost $30. it works like a charm! 14.5 on the gauge at all times.
i also added some relays for my headlights and i have no voltage issues at all now.
i also added some relays for my headlights and i have no voltage issues at all now.
