gnathv
Full Access Member
Cycle glow plugs without starting and then check voltage, see if the are less than 12v
Cycle glow plugs without starting and then check voltage, see if the are less than 12v
Before I go any farther I am going to clean the contacts on both positive battery terminals. They look fine but I don't think i've ever had them off.
12.7 after sitting before start
11.2 during glow time not started
12 while afterglow truck running
14.5 after glow times out
what does yours do during these events.
I read that at 9.6 v under load it’s time to replace.
I would also clean the grounds both at the terminals and at the block. Bad grounds cause more issues than just about anything.
Look up "how to full field 3g alt" and try that, it will give the maximum charging capability of the alternator(according to the set point on the reg), disregarding the voltage input to the regulator.
This will tell you a lot, like if it's capable of more and is just stuck low for some reason. If that's the case then it's not sensing the correct voltage(I think the yellow wire?). Whichever wire is the sense needs to go to the battery + terminal or the starter relay + on the fender. Both are fine.
Full fielding it gives the alternator's max voltage it can create, but it doesn't check the rectifier or diodes for failures. Which is likely where your problem lies.
With the engine running, set your meter up to measure ac voltage, and connect the positive end to the alternator's B+ terminal and the negative end to the alternator case.
Anything more then .5 volts ac shows diode damage and the rectifier requires replacement.