Most wasted mpem

[hotrodssnova]

This happened today.

What the hell?
I've tested the mag. Ohmed out at 0.02. Puts out 45 volts ac. New voltage reg. Battery was fully charged and showed proper charging at idle and 5500 rpm.
Just a bad mpem?

I've been blowing the 5 amp fuse, but it has been random. It'll run for an hour, blow. Run for 2 min and blow.
Kinda at a loss here, not to mention a fried mpem.

 

[mikidymac]

Does your VTS work? They are known to fry MPEM's.

 

[hotrodssnova]

Everything works. I'm baffled. Even the vts gauge works.
I even replaced the wires from the stator to the e box. Couldn't stand how short it was.
All tests we're done with the new wires. That came from a 97 gtx.
All tests we're perfect. My battery still shows 12.7 volts now.
Swimming with a ski in tow sucks!
I'm thinking its a bad mpem.
I ordered on from eBay, and it wouldn't charged the starter solenoid. Have to send that back.
I went thru the whole system, even tested each wire with a wiggle and found nothing.
This is the 96 xp 787 in my "new adventure " thread.

 

[Sportster-2001-951C-Stock]

Hmm, so does that MPEM still work? I'm also nervous about the VTS, disconnecting it will eliminate the possibility.

And I'm not familiar with that particular MPEM but if it's made like the others it will have an over voltage surge protection diode internally, on the output side of the 5A fuse. These diodes are notorious for developing a short and causing the 5A fuse to blow (and perhaps some other odd internal failure, it's unclear).

[MENTION=41828]Minnetonka4me[/MENTION] Don't forget Nick, he's a good source for spare parts.

 

[hotrodssnova]

The mpem does not work. It is smoked. I'm gonna try another mpem I have. Needed to get some fuses. I'll have an update today with what I find.
Gonna try unplugging the vts, voltage reg, new battery. All this stuff I have in the other ski. And go from there.

 

[Minnetonka4me]

Was that ebay one a oem or aftermarket?

 

[hotrodssnova]

It was the original one. Dated 4/11/96. 278000510

 

[hotrodssnova]

Quick update.....
Unplugged vts from the small box in back, unplugged small single wire by e box, and red wire from regulator. Still popped 5 amp fuse. Unplugged large 4 prong plug from e box started up. Plugged regulator in and started, charging at 13 5 at idle, then major rain hit. So, had to stop there. Looking like a vts issue.
I noticed that my vts gauge is smoked also. Looks like one major system fail . Can't even see the needle it's so bad. Didn't even notice it till now.

 

[hotrodssnova]

Last update. ......I hope.
Vts fried everything. From the mpem to the gauges.
I tested the purple wire against the black wire and showed a short. Same again on the red and purple to black also a short.
Got a spare vts installed, and another hood installed (actually needed to do that, the original was damaged). Unfortunately, the center gauge is dead. Not sure about speedo. Vts gauge is working perfect.

Now maybe I can FINALLY ride the ski for once.

 

[Sportster-2001-951C-Stock]

Ouch, seems like the original harness should have included a fuse or two to avoid this.