I've an 09 SG. ~ 20K miles. Sorta new build including S&S cams, 106" BB, ThunderMax. New HD battery and recently replaced cruise switch.

SOME UPDATES AND, AS NOTED BELOW, IT WAS THE ECM FUSE

Rode for awhile tonight and bike ran beautifully as usual. Got home, shut it off to open garage. On restart it popped for a second then died. Now cranks like crazy but no fuel pump prime action. I'm not an electrician....

Here's what I've done/know:

The CEL did not illuminate and, using the tack, the bike threw no codes.

When I turn the ignition on and flip stop/run to on, no fuel pump prime sound and won't start (but cranks).

Bike cranks when stop/run is on but not when it's off. Does this mean fault is not in the stop run switch? Correct

Fuel pump fuse appears good, plus I traded it for another. Still no prime.

Start and brake relays have same part no. When I switch one for the other, brake light activates but no fuel pump prime.

System relay is different part no but same shape and connectors. When I put it in fuel relay slot, still no pump prime.

I hunted around for loose wires under seat etc. Nothing.

Ideas?

Many thanks

Jef

My wife said the problem was caused by my washing the bike so much. ... I do think I'll no longer use the leaf blower for drying.

 

I would start with the simple things: check your grounds, and battery cables first before you start diggin around

 

I can only suggest a multimeter and wiring schematic.
Start at the relay and determine if it is getting juice there, if it is chase away from the relay, if not chase back to ignition. Sounds like you have ruled out relay.

 

The files may by corrupt in your ThunderMax I have seen this happen more than once.

 

You may want to check "filter shell" inside the tank. I had a similar problem back in May. I pulled the filter shell and found it cracked. Your pump may be priming, its just not noticeable because its not building pressure.

 

Because I've a great mechanic (Mike at Ironworks in Gaithersburg, Md) and this is beyond my level, it's going to the shop tomorrow. I'll report back. Thanks.

 

Fixed. It was the ecm fuse .....(I carry fuses and use dielectric. grease but didn't check that one.) Mechanic said he's unsure why it blew but told me to stop using the stop/run toggle to kill the motor, because that causes voltage spikes.

 

Glad you back up in running but I'm not sure I buy into what your mechanic said below.

 

Glad its fixed, but his advice makes no sense. There is nothing wrong with using the run switch to shut it off and start it up.

Carry an extra fuse if you want and keep using it. I doubt it will ever blow again.

 

another update

Blew a second ECM fuse Friday morning as I was leaving for Ocean City Bikefest. .... I decided to replace the fuse and ride to the Zippers/Thundermax tent at the festival and see if they could figure out why I was blowing fuses. But, had to finally fix something first.

For about a year I've been having intermittent issues with my Kury running lights: The power has been unstable, which I knew because the green running light on the HD aux toggle I installed would go out. When it would do so I could reach under the fairing cap and shake the wires and it'd come on. So, before leaving I traced all the wires and found two connectors that were not fully inserted and one Kury-supplied connector that had insufficient shielding. (I hate lame electrical connectors on the expensive stuff we buy.) No other faults. I tightened and wrapped with tape. Now I can shake the wires like a gorilla and no flickering power. Rode 600 miles, started and stopped a zillion times, fuse is good.

The Thundermax tech found no problems. When I later told him about the lights he said that "definitely" could cause the ECM fuse to blow. He said the circuits are close-enough together that the bad connection could cause a spike in the ECM circuit. Maybe that was it.

BTW, T-max issued a software update 'just before Sturgis." Helps with starting and probably other stuff.

Bike ran like a dream. For me, the Bay Bridge is scary every time.

Hope all of this helps some of you. -- Jef