2G Alternator not charging, Help

[jcr]

Hi, does anyone have an alternator pinout
With colors? I have a 95 gsx and it literally has a rat nest of wires and its not charging. Can someone give me oem colors and positions on wires?

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[steve]

Looking at that and your other posts I think your going to need many of the files in our resources section. https://www.dsmtuners.com/forum/articles-manuals-documents.262/ Take a look around.

Here's the 2G alternator diagram.

You must be logged in to view this image or video.

And a little about the ECU control of the 2G alternator.

You must be logged in to view this image or video.

 

[jcr]

Hi guys! I need your help.
I have a 95 GSX, it has a black box ecu MD359403 (According to my research from a 99).

Anyway, my alternator is NOT charging. I check relay and dummy light. The light will not come on. I checked the bulb and bulb is good! But it won't light up. What else can I check?

What reading should i get at pin 33 and 41 from ECU?

 

[steve]

From the 2G DSM Technical manual:

GENERATOR G TERMINAL (ECU pin 33)
The engine control module limits the generator output current by duty control of the continuity between generator terminal G and the ground.

When there is no continuity between generator terminal G and the ground (let this be 100% duty), transistor No. 1 (TR1) stays in the always ON state. When the voltage at generator terminal S reaches 14.4 V, the power transistor is forced to OFF to adjust the generator output voltage to 14.4 V. This operation is the same as that of the conventional generator.

When generator terminal G is short-circuited to the ground (let this be 0% duty), the TR1 stays in the always OFF state. In this case, when the voltage at generator terminal S reaches 12.3 V, the power transistor is forced to OFF to adjust the output voltage to 12.3 V. Since the voltage is lower than charged battery voltage, practically no current flows from the generator.

GENERATOR CURRENT CONTROL

During the period the engine is in operation, the ECU achieves duty control of the continuity between generator terminal G and the ground. (In this case, the OFF duty of terminal G is controlled to equal the ON duty of the power transistor in the voltage regulator.)

Operation of the headlights causes a sudden increase in current consumption, but the ECU suppresses a sudden increase in the generator output current, thereby preventing the sudden increases in electric load from abruptly reducing the engine speed while the engine is running at idle. (During the period before the generator generates enough power, the battery current is additionally supplied to the headlights, etc.)

During the period of approximately 0.5 seconds after the power steering pressure switch has been set to ON and also during the period of approximately 0.5 seconds after the selector lever has been changed over from the N range to the D range, the ECU controls generator terminal G in terms of 30% OFF duty to suppress generation of power by the generator.

Under the following conditions, however, this control is not achieved:

High engine speed.
Engine coolant temperature 50°C or lower.
Air conditioner switch ON.
More than 0.5 seconds after the power steering pressure switch has been set to ON.
More than 0.5 seconds after the selector lever has been changed over from “N” to “D”.
Three seconds or less after the engine has been started.

When a high signal at generator terminal FR (ECU pin 44) lasting for more than 20 seconds is input to the ECU during operation of the engine, the ECU determines that the generator terminal FR circuit has been open-circuited and stores diagnostic trouble code (No. P1500) in memory, and places generator terminal G in the always OFF state.

You must be logged in to view this image or video.

Make sure you're getting battery voltage to the B+ stud (all the time), and pins 2 and 3 of the alternator connector (when the key is on). No light on the cluster is a initial failure mode indicator.

 

[TheFlashDSM]

Saturn alternator swap

 

[99dsmer4g63]

Have you fixed the nightmare of a wiring job in the original post?

I would suggest trying to return the wiring to the way the factory intended it to be. Looked like it’s hacked up pretty damn good.

I would also pop the alternator off and take it to a parts store for some free testing to see if it passes or fails too. These alternators have a hard life living next to the exhaust. On top of that power steering and water pipe leaks or even someone recklessly working above it letting fluid soak it will kill them quickly as well.

Being a 95 I believe you should also have a relay near the fuse box for it as well.

-Daniel