Hi,
Problem involving power, the car is charging the battery but its almost like its using more than its giving? Swapped altenator and its not that but dose it go through a relay? As soon as i put lights or heater on she drops below 12v to 11v but cant seam to figure it out im trying diffrent batteries as well, helo would be appreciated
Its a ca18det btw
Check and clean the engine and body grounds also make sure the alternator terminals are clean.
Did you connect the plug, the large wire and the small wire
Does the light on the dash come on ?
As above most likely a poor ground on the engine/body or if your using a gauge type voltmeter in the car it may be a bad ground on that causing false readings
Checked all grounds and cleaned incase, everythings attached and light is not on in the car
Whats the voltage at the battery with everything off but engine running
Is it on when engine isn't running?Originally Posted by s13spooner
12v with everything off just engine running, no lights off
The alt should be putting out close to 14V when engine is running.
As you have swapped the alt it's probably not the alt. Also I think we can assume you have an alt belt and it's got some tension.
Is the charge warning light lit when you switch on and before starting? The alternator needs the low current it draws though the bulb to start working. It is connected to the alt rotor (field) coils.
Check the big grey 75A alternator fuse with a transparent lid in the engine bay fuse box.
If an alt has not been run for time it may have corroded slip rings or have lost too much residual magnetism. Corrosion can sometimes be cleaned off by revving the engine to >4000rpm for a few seconds. Likewise for reduced magnetism as output volts are dependant on strength and rate of cutting the field, so higher speed compensates for reduced magnetism. Once you get some volts from the stator it will feed current to the rotor and re-magnetise it.
Update: checked everything again all earths ect, and came to the solution of replacing the altenator again for another one, also ran a brand new battery and its FIXED! seams it was a combination of them two just now need to relocate the battery to the boot, thanks for your suggestions much appreciated!
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