Fast Idle and Wonky Tach

[Alpha Dog Custom Cycles]

I did manage to find the right wiring diagram, and in fact, the whole service manual.

 

[Mr. Wright]

k, let me think some more.

 

[pknowles]

I had a similar problem when I installed the wire+ on my 07 Bulldog. If I remember it was having to install a constant hot wire from the vfi? That was about 9 years ago. After I quit drinking this afternoon I will try to find my notes. If you can contact Tom(GROUNDPOUNDER) he helped me with mine.

 

[Mr. Wright]

Paul's on to something here, witch bring me back around to what I was thinking. You have a ground problem somewhere. With that constant hot wire on there, if it has a ground problem, it will start grounding through any thing it can find. Hench you high idle problem too.
I'm going to start with the most obvious, and go back to the headlight. Did you just put a hot wire at the EHC to check that circuit, or did you isolate it. If you have a bad ground at the headlight, it will ground itself back through the high or low beam.

 

[knothead]

Paul's on to something here, witch bring me back around to what I was thinking. You have a ground problem somewhere. With that constant hot wire on there, if it has a ground problem, it will start grounding through any thing it can find. Hench you high idle problem too.
I'm going to start with the most obvious, and go back to the headlight. Did you just put a hot wire at the EHC to check that circuit, or did you isolate it. If you have a bad ground at the headlight, it will ground itself back through the high or low beam.

Thats why i talked to you about this particular bikes problem you explain things better than i can lol...

 

[Alpha Dog Custom Cycles]

Paul's on to something here, witch bring me back around to what I was thinking. You have a ground problem somewhere. With that constant hot wire on there, if it has a ground problem, it will start grounding through any thing it can find. Hench you high idle problem too.
I'm going to start with the most obvious, and go back to the headlight. Did you just put a hot wire at the EHC to check that circuit, or did you isolate it. If you have a bad ground at the headlight, it will ground itself back through the high or low beam.

I have a good ground at the headlight socket. 0.3 Ohms to ground.

I isolated the headlight circuit by unplugging at the EHC. From the pin in the plug to the bulb socket, I get 0.3 Ohm. Infinite Ohm to ground. If I apply power at the EHC plug, (disconnected from the EHC,) I can illuminate either the low or high beam. My fault is happening somewhere other than the wiring to the headlight.

 

[Jersey Big Mike]

Since you have the schematic, I would jump a wire from battery neg directly to EHC ground, with as much disconnected as possible power up -- add one thing at a time till it goes wrong. Process of elimination.

 

[Rottweiler]

When you said this earlier.

What is so infuriating about it is that everything was working except the tail lights and right rear turn signal. I tracked down those faults and all lights except the headlight work just fine now. The headlight worked before I fixed the tail lights.

Maybe go back and take another look at the right rear turn/ brake light.

 

[Alpha Dog Custom Cycles]

When you said this earlier.

What is so infuriating about it is that everything was working except the tail lights and right rear turn signal. I tracked down those faults and all lights except the headlight work just fine now. The headlight worked before I fixed the tail lights.

Maybe go back and take another look at the right rear turn/ brake light.

I DID go back and look at that. No doubt, I will look at it again. The taillights, brake lights, and turn signals are working just fine, though.

 

[Alpha Dog Custom Cycles]

Since you have the schematic, I would jump a wire from battery neg directly to EHC ground, with as much disconnected as possible power up -- add one thing at a time till it goes wrong. Process of elimination.

I have to spend some time studying the schematic. Initially, I was going over the schematic for the carbureted version but having the wrong schematic was not going to work in my favor. After a little Googling, I found the complete service manual, including the EFI version of the schematic.

 

[Rottweiler]

Looking at the wiring dia. low beam is on Bus 1 and high beam is Bus 2.
I believe you said you tried both and they both trip the internal fuses?
Question What style headlight are you using H4 or LED?

 

[Alpha Dog Custom Cycles]

This is to report back to the group what I did to resolve this.

One responder said that the EHC switches to high beam if the low beam burns out and that sometimes the solid state "fuse" in the EHC can fail when this happens. This appears to be what happened. The low beam filament burned out while I was troubleshooting the tail light and turn signal circuits.

I decided to bypass the headlight circuit in the EHC altogether. I used a connection on the EHC that is powered when the key is turned on to trigger a 30 A headlight relay to power up the headlight. I ran 14 ga wires to the headlight bucket to carry power instead of the ridiculously small gauge wired originally used. Now the challenge was controlling high/low beam. The button on the handlebar control is a momentary contact button rather than a switch with two positions. I installed a toggle relay in the headlight bucket that is designed to work with a push button.

Drag Specialties® - From our garage to yours

Drag Specialties is the world’s largest distributor of aftermarket accessories in the powersports industry.

www.dragspecialties.com

I used one of the small gauge wires that originally powered the headlight to send the signal to that relay. I used another one of the original wires to send power to the high beam indicator light.

Thank you everyone who took the time to help me brainstorm this problem.