'94 900SS fuel pump issues

[PeterB]

Hi All,

I have a '94 900SS and I've had a wierd intermittent problem that I'm looking for some advice on. This has happened only 3 times, I turn the key to the "on" position and instead of the normal fuel pump sound I get a really low noise and no other electrics work, no lights, horn nothing. The first time I just turned the key on and off a few times and things were back to normal. The next time I pulled the fuel pump fuse and then put it back in and all was fine. The last time I was letting the bike warm up when it just stalled with all electircs shutting down. I took the cover off the fuse box, turned on the ignition and all was good again. I had the bike out for an hour ride after that with no problems. Seems to be a short somewhere or would this be a sign of a bad fuel pump? Any suggestions?

Thanks,

Peter

[Shawn]

Hi Peter,

What is the battery voltage with the bike not running and idling? Supersports are famous for frying the voltage regulator.

Otherwise, the list below should give you an idea of where to start with your SS electrics.
a)Check battery connections & frame to ground connections. These should be free of rust/corrosion to ensure proper contact.
b)Check battery cables for corrosion/cleanliness.
c)Check all fuses for continuity. Actually pull the fuse out and check for a bridged connection as it could be cracked and re-establish contact when you move the fuse around. Don't ask me how I found this out, 2 hours later.
d)Check main relay - square black box in the rubber grommet on the right side of the fairing support.
e)Check ground cable for voltage regulator and main ground wire(Socket head cap screw) that is mounted under the dash to the fairing stay but above the headlight.
f)Check to see if all electrical connectors are clean/secure and that there aren't any wires missing insulation causing a short.

Shoot me a PM if you need a PDF copy of the electrical schematic that is in the factory service manual.

I hope this was of some assistance. Best of luck.
Shawn

[PeterB]

Thanks Shawn for all the advice. I was thinking voltage regulator too. I guess I need to roll my sleeves up and get into the electrical system. I will shoot you a PM for the PDF, I just have the haynes manual. I have also noticed my headlight seems dim on low-beam and its always been that way since for the 8 years I've owned it.

Thanks,

Peter

[The Goochman]

Check the ignition switch as well. After 20 years they sometimes start making intermittent contact.

[markk900]

Both Shawn and Gooch give good advice, but I wanted to point out that your symptoms are not that of a voltage regulator failure (I've experienced 3 on various Ducatis over the years, plus a couple on eastern machines - such is the price of liking old bikes). If the regulator fails either the battery will over charge (and boil off the electrolyte), or it will not charge enough (leading to the battery going flat eventually). Neither of those circumstances leads to intermittent total system failure (and recovery by poking and prodding).

Dave is probably right that an intermittent contact in the ignition is the culprit (almost as many bad ignition switches on italian bikes as there are bad VRs), but Shawn's advice may also help locate another loose or damaged connection elsewhere.

Mark

[PeterB]

Thanks for all the advice guys, I finally discovered the problem...a bit of corrosion in the main fuse connection. It seems I had a tad bit of rust on one of the contacts which caused some arcing. The fuse was actually slightly melted but not blown. I cleaned up the area, tightend up the contact, applied some dielectric grease and inserted a new 30amp fuse and all is good. That was a wierd one for sure.

Peter