Charging problem!

[jaed_43725]

  Ok, so when I start the car and blip the throttle to 2K it goes up normally. After that the tach just goes to like 600 RPM and then slowly drops from there. I can tell its not charging because the fuel gauge and water temp gauge both slowly fall. By slow here I am talking about 40 miles and the battery is dead. I have a new alternator which is tested good, the belt tension is good. The only thing that is old is this black thing on the back of the alternator that has a blade plug in and its held on by an 8mm bolt. Any help is greatly appreciated. I don't want to have to take this thing somewhere but if I have to I will.

[ORCoaster]

Perhaps a broken wire along the line somewhere.  Makes contact then does not.  Clearly you are not charging up.

[TylerDurden]

Not charging and/or the GP relay stuck.

Unless the accessories are on (lights, fan etc.) a battery should keep a diesel engine running for hours (if not days).


I would charge the battery and test:
 - Meter the battery, should be ~12.5V
 - With the ignition switch in the ON (run) position, but engine not running, the battery should read ~11.5V until the GP relay opens (~20sec), then back to ~12.5V.
 - Meter between battery neg and blue wire at the alternator D+ terminal should be ~1.5V.  The dash LED should be illuminated.
 - Meter between battery neg and big red cable at alternator B+ terminal should be ~12V.

Start the engine:
 - Wait ten seconds and rev the engine once to 2000rpm
 - Battery voltage should read ~13.5-14.5V
 - Blue wire at D+ terminal on alternator should read the same as battery
 - LED on dash should not be illuminated

If these check out ok, then it is likely a connection problem with grounding.

(The black module is a condenser to suppress RFI from interfering with your AM radio... not important.)

[scrounger]

Is this your new alternator. Might be better as a followup  to your original thread. "Whats the best alternator"
Keep reading.

TD Give up AM radio. No way, how am I going to find out what is going on the world.

[jaed_43725]

I am gonna do the checking then. I hope its not serious, but then again there aren't many wires on this thing. I read somewhere someone changed all their little wires for substantially bigger ones and it made quite a difference. If everything checks out then I am gonna have to drop it off at Apex Tuning.