LSD Diff Shorting out fuse #46

[joe1602]

After changing the open diff on my 99 with an LSD from an earlier model year. I have been blowing the #46 fuse. I replaced it with a 20Amp fuse and that blew right away as well. Replaced the fuse again with a 15 amp, unplugged the diff, no fuse blown but not speedo either. I knew that would happen if I unplugged it. Question is: What is causing this? did I miss a ground or do I need to change the sensor/plug in the diff? Any ideas would be greatly appreciated! Thanks

[M-technik-3]

Your car had traction control and still thinks it does, so you need to disconnect the traction control.

The LSD and the Traction Control are effectively fighting each other and electronics generally loose to a mechanical item. Never Never put a larger fuse in a circuit than it was rated for unless you would like a possible wiring fire.

[joe1602]

I wondered if it was something like that. Any idea on how I disable the traction control? I already have the traction control and ABS lights on my dash due to a bad right front wheel speed sensor. Never really wanted to fix it as I disable it anyway for autocrossing. Do I still need to turn the switch off in the cabin or do I need to disable a fuse or disconnect a certain wire? Thanks for the help, I really appreciate it!

[M-technik-3]

I would disconnect the butterfly electronics that regulate the airflow and I would down load a copy of the ETM Electronic Troubleshooting Manual for the 99 as it does have differences year to year.

Then I would just remove basics so If you were to sell the car you could reverse it to someone that wants that for there kid.

[joe1602]

Does anyone know if there is a diy for this? I did a search but didn't come up with much. I am really limited in experience when it comes to electronics and fuel injection!

[joe1602]

What would happen if I just pulled the 3 fuses for the ABS & Traction Control? #'s 10, 21, and 38?

[BlackBMWs]

Originally Posted by M-technik-3

Your car had traction control and still thinks it does, so you need to disconnect the traction control.

The LSD and the Traction Control are effectively fighting each other and electronics generally loose to a mechanical item. Never Never put a larger fuse in a circuit than it was rated for unless you would like a possible wiring fire.

Interesting... I installed a 3.45 LSD in my 97 Sport and I am not having an issue. I have traction control (ASC) as well and it turns on and off just fine.

I am about to install a 3.45 LSD in my 98 sport as well, so if this is an issue, it's good to know, although I'm not clear how speedometer readings from the diff affects the ASC operation.

Thanks for the feedback!

[joe1602]

I am going to pull the 3 fuses later today & plug the diff back in. I will let you know what happens.

[joe1602]

Pulled Fuses #10, 21, 38. Plugged the LSD back in. Drove around for about 10 min, some of it very hard, all seemed to work well, Brake lights OK, On board computer fine. I will keep an eye on it to see how it goes.

[BlackBMWs]

Hmmmmm. I installed a 3:45 small case LSD on my 1998 318ti Cali Sport. No electrical issues. I wonder if it a 1999 model year thing? I'll be installing. 4:45 LSD on Wifie's Active auto. I'll note if any electrical issues occur.


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