I'm back

[callison]

Finally got internet at my new house about 35 minutes ago. I don't want to go into the costs of satellite hookups when residing in the hinterlands.

 

It's rained nearly every day since we moved in 3 weeks ago so I rewired all of the stuff I added to FrankenSport figuring that it was something I did that causes the ECU fuse to fry whenever the throttle is whacked open. Once it finally stopped raining long enough for me to screw up the courage to ride the 4000 feet of newly oiled gravel road that passes for the main drag in my housing area, I headed for the immortal Route 66 to try out the repairs. Crap and damn!!! The stupid fuse still blows. More things to do I suppose...

 

Went to the local club races at Hallet Motor Speedway last Sunday with two friends - one on a Triumph Triple and the other on a 2002 LeMans (champagne). Nice to know that I only have to go 56 miles to get to the races.

[Cliff]

This is not the fuse for the fuel pump is it?

 

What sized fuse is it. Try putting a meter in series with fuse to see what the normal current is and how it changes.

[callison]

This is not the fuse for the fuel pump is it?

 

What sized fuse is it. Try putting a meter in series with fuse to see what the normal current is and how it changes.

58447[/snapback]

 

It's the fuse to the ECU. Tried two different ECU's too. No joy. Only happens when riding the bike. Maybe it's a seat vs relay thing. Baffled and a bit PO'd as the bike is ready to go except for this little "quirk".

[Cliff]

The ECU does not draw much power from +12V - perhaps 100mA. All the load is controlled by pulling things to ground. I can't see where 5A would go inside the ECU.

It sounds like some short in the harness.

[callison]

The ECU does not draw much power from +12V - perhaps 100mA. All the load is controlled by pulling things to ground. I can't see where 5A would go inside the ECU.

It sounds like some short in the harness.

58458[/snapback]

 

I've bought a used harness just because of this problem and the state of exasperation it has brought about. Eventually, I'll find which box it was shipped in and start the replacement process.

[Murray]

Stupid suggesting but maybe we are over looking possibly the obious. When you apply full throttle is kinda odd the bike is already running things that are drawing current are drawing current. The only thing that starts working hard and drawing more current are the coils. The alternator starts to produce more voltage at higher rpm but this seems to be a throotle postion problem not a rpm problem. Have you checked the harness that runs near the throttle cables and linkages how about in the throttle body. The linkages or cabe could of rubbed through somewhere and when you apply full throttle short something to earth. Dunno its only an idea the other thing to look at is to make sure the coils are solidly mount and not touching something when the bike suddenly accelerates forward.

[callison]

Stupid suggesting but maybe we are over looking possibly the obious. When you apply full throttle is kinda odd the bike is already running things that are drawing current are drawing current. The only thing that starts working hard and drawing more current are the coils. The alternator starts to produce more voltage at higher rpm but this seems to be a throotle postion problem not a rpm problem. Have you checked the harness that runs near the throttle cables and linkages how about in the throttle body. The linkages or cabe could of rubbed through somewhere and when you apply full throttle short something to earth. Dunno its only an idea the other thing to look at is to make sure the coils are solidly mount and not touching something when the bike suddenly accelerates forward.

58473[/snapback]

 

Not stupid suggestions at all. I've looked, but perhaps I've overlooked something. The fuse only blows when actually seated on the bike and accelerating. On a stand - no problem. Accelerate slowly - no problem. I can even run it near redline without problems. Exceed redline though and the fuse blows. I must have gotten something wrong when I put the bike back together after it was totalled. Eventually, I'll get it resolved. Alternatively, I may just part the thing out and stick the (better) engine/exhaust in my Sport 1100i.

[Guest Nogbad]

Put a nail in the fuseholder. This will cause the fault to blow something else allowing you to find and rectify it. If nothing blows, leave the nail in there. Problem solved.

 

(Need a tongue in cheek smiley!)

[jrt]

Can you tell if it is throttle position or engine speed that causes the fuse to blow? For example- does it happen if you wack the throttle open at 2500 rpm, or only at 5000+ or either?

[txrider]

The seat-relay thing you mentioned might be the item to take another look at. Can you see under the seat with all aft body work removed? The wiring under the fuse holder and the relay holder could be stressed if the seat is resting on either with you aboard. A subtle shift in seat position upon accleration could then allow a shorting condition if wiring is chafed but touching intermittenly. Is the ECU mounted where it clears the seat with you on the bike? Or can you make up some spacers to raise the seat and then redo the acceleration/rpm test?

[badmotogoozer]

Sure does sound like it is your seat shorting something out when your weight is pushed back hard. Have you tried jumping around on the seat at idle to see if it blows? Sounds silly, I know...

 

I remember there isn't much room under there and I did have to hog the seat pan out with a dremel as it was cutting into my battery strap.

 

other than that...????

 

Ryan

[beauchemin]

The problem might not be from simply sitting on the seat (to test, try standing on pegs while accelerating). Could it be some indirect result of loading the engine, which you won't get during stationary running? Good luck with this head scratcher!