Voltage drop when decelerating and gauge jumping around.
Voltage drop when decelerating and gauge jumping around. I have been fighting weird voltage issues for a few days now. At first it would run about 13.5 for about an hour of driving and then voltage would drop while cruising to around 10 and wreak havoc on my AFRs. I discovered my positive side terminal was stripped and barely making connection. Now when I start off I get 14.5 for about 15 or so minutes, I am assuming this is where it should have been all along, and then it drops to 13. to 13.5.
Now the weird issues are if I am cruising after it warms up and I let off of the accelerator my voltage drops from 13+ to about 11.5 for a second or two and then climbs back up to 13+. Also at a stop light it will jump around from as high as 14+ to as low as 12.9ish, just below 13 but never stays that low. I do have an under drive pulley on it so maybe thats causing some of it??
I had the alternator checked and it was good. I am thinking maybe the battery has been under/improperly charged for a while now because of the terminal and that has weakened it, even though it read 12.5 at rest.
Any of this sound feasible to anyone else or anyone have any thoughts on it?
Thanks!!
Now the weird issues are if I am cruising after it warms up and I let off of the accelerator my voltage drops from 13+ to about 11.5 for a second or two and then climbs back up to 13+. Also at a stop light it will jump around from as high as 14+ to as low as 12.9ish, just below 13 but never stays that low. I do have an under drive pulley on it so maybe thats causing some of it??
I had the alternator checked and it was good. I am thinking maybe the battery has been under/improperly charged for a while now because of the terminal and that has weakened it, even though it read 12.5 at rest.
Any of this sound feasible to anyone else or anyone have any thoughts on it?
Thanks!!
After driving around today I think it is working ok, maybe the battery is finally getting a good charge? Anyway it still drops sometimes when I let off of the accelerator but always comes right back up. Will an under drive pulley cause this issue?
I had my battery and alternator both load tested and they came back ok but it still does it and I also get some flickering so I really have no clue.
My new issue is if I drive around for about an hour my afrs go lean at cruise and if I try and get into boost it goes off the scale lean and sputters so I'm having some issues right now.
My new issue is if I drive around for about an hour my afrs go lean at cruise and if I try and get into boost it goes off the scale lean and sputters so I'm having some issues right now.
the alternator has a minimum rpm rating for it to provide an acceptable power output. what that actual value is i'd have to look up, but on a stock motor the pulley of the alternator is small enough compared to the crank pulley to allow it to spin fast enough at idle rpm which for an auto is usually 600 rpm.
if you know the under-drive pulley ratio, you can calculate % of how far below the stock idle rpm the alternator is now turning, which is most likely your problem at idle rpm's.
it is normal after starting the motor for voltage to be up to 14.5 volts, then drop to around 13-13.5v after engine is hot and battery is fully charged. under normal circumstances you should never see the volt gauge in cluster go below the middle 13v mark. if it dips below that mark at idle rpms but comes back above the 13v mark with higher engine rpm's then that's the result of your underdrive pulley
if you know the under-drive pulley ratio, you can calculate % of how far below the stock idle rpm the alternator is now turning, which is most likely your problem at idle rpm's.
it is normal after starting the motor for voltage to be up to 14.5 volts, then drop to around 13-13.5v after engine is hot and battery is fully charged. under normal circumstances you should never see the volt gauge in cluster go below the middle 13v mark. if it dips below that mark at idle rpms but comes back above the 13v mark with higher engine rpm's then that's the result of your underdrive pulley
the alternator has a minimum rpm rating for it to provide an acceptable power output. what that actual value is i'd have to look up, but on a stock motor the pulley of the alternator is small enough compared to the crank pulley to allow it to spin fast enough at idle rpm which for an auto is usually 600 rpm.
if you know the under-drive pulley ratio, you can calculate % of how far below the stock idle rpm the alternator is now turning, which is most likely your problem at idle rpm's.
it is normal after starting the motor for voltage to be up to 14.5 volts, then drop to around 13-13.5v after engine is hot and battery is fully charged. under normal circumstances you should never see the volt gauge in cluster go below the middle 13v mark. if it dips below that mark at idle rpms but comes back above the 13v mark with higher engine rpm's then that's the result of your underdrive pulley
if you know the under-drive pulley ratio, you can calculate % of how far below the stock idle rpm the alternator is now turning, which is most likely your problem at idle rpm's.
it is normal after starting the motor for voltage to be up to 14.5 volts, then drop to around 13-13.5v after engine is hot and battery is fully charged. under normal circumstances you should never see the volt gauge in cluster go below the middle 13v mark. if it dips below that mark at idle rpms but comes back above the 13v mark with higher engine rpm's then that's the result of your underdrive pulley
