2002 LeMans voltage regulator - help!

[Doansci]

19 hours ago, LaGrasta said:

As I just went through this, allow me to advise also running a power lead directly to the battery, just as https://www.electrosport.com/ suggests. Until I did this, I could not get mine to work properly.

LaGrasta - this makes sense, but I wasn't able to find the instructions at electrosport.  Do you run it through a fuse or circuit breaker like Docc suggests?  

Tomchi, AudioMick and Docc - I do recall that the ground was to attach to the engine.  Perhaps my memory confused this with a power wire like LaGrasta describes?   I will reroute it when I install the new regulator.

Docc - I tried to find Caig Deoxit a couple years ago and looks like it is mail order only for me.  The connectors are bright and shiny.

Speedfrog - the replacement regulator is arriving today so maybe mosfet next time.  The description of the electrosport regulator also looked good. 

To everyone - I really appreciate your quick and detailed help.  Your knowledge and willingness to help are impressive.  Thank you.

 

[LaGrasta]

https://www.electrosport.com/products/esr510-regulator-rectifier-ducati-1-phase-charge-light-output?srsltid=AfmBOortB9sbJb7q3HYBe3GMkx3e6d1ivf6qCarA7-guJyFeqcfzUss2

 

[Kiwi_Roy]

On 7/6/2025 at 4:01 PM, docc said:

 

My recollection is that this applies to the small gauge factory regulator ground back through the loom to the battery.

Yet, there is wisdom in making a short, robust ground from the regulator case to the engine/timing chest as long as the main battery ground to the back of the gearbox is reliably serviced.

Comments, @Kiwi_Roy ?

edit:

(Inadequate) factory regulator ground wire after failed main battery ground to rear of the gearbox:

Yes, make sure your main ground is good, typically it runs to a 6mm bolt at the rear of the gearbox The regulator also needs to be well grounded, i prefer that to be a short jumper to a timing cover screw rather than back to the battery.

I think we figured that this picture was the result of a bad main ground,. On starting the starter current 100+ Amps tried to get back to the battery via the small wire between the regulator case and battery Negative the massive engine and gearbox castings are a better path than a wimpy copper wire. Better that the starter doesn't work than frying the loom.

Edited July 20 by Kiwi_Roy

[Kiwi_Roy]

On 7/6/2025 at 3:51 PM, audiomick said:

If I recall correctly, the reason for that is that if ground connections elswhere go bad, the connection from the regulator to battery negative could end up trying to be the main ground for the whole wiring system, and get fried.

Thats right the tiny ground wire will get red hot and weld itself to other wires in the loom

This happens while cranking up to 150 Amps, there's a photo on here somewhere