bike cuts off completely

Coolbreezin

Active Member
Thank you all for the input. If nothing else, I have a better understanding of how everything inter-connects and interacts with each other.
As for the headlight, replaced that twice, once in 2008 and just about a month ago (wanted a blue light to match the paint). Everything was in good condition, just a little dirty. Wiped it all clean and reinstalled.

Ill be getting the coil cover painted this month so Ill ck the guts for eveything mentioned above while its apart.

Thanks again.
 

Sven

Well-Known Member
If nothing else, I have a better understanding of how everything inter-connects and interacts with each other.
Bad,

It's a needle in a haystack to keep guessing which is what without being on top of the bike yourself. So, in the generic, I throw out the grasp of the subject. Then maybe the OP can work that concept out, not go blind into it. Just a little bit of theory helps, no?

I agree with you I don't know the specifics of the EHC. Now I (some others) know. Thanks! :up:
 

1goodsinner

Member
Just remember,most guys on here who proclaim your problem to be the EHC replaced it without the problem actually being the EHC. They were incorrectly told that the EHC is the root of most problems on the BDM. It's usually electrical,outside of the EHC realm.
 

RRRUFF

Well-Known Member
Mine was doing exactly as yours. I put a toggle switch in place of the key switch to rule that out because I didn't want blame the ehc and fork out big $. Fortunately that fixed my problem and I replaced the key switch. I agree that alot of electrical problems get blamed on the ehc and sometimes the ehc is the culprit. But usually a failed ehc is because of some other electrical problem that eventually takes it out. I always start with the simple stuff first and work my way up. Simple stuff, key switch, loose connections, bad crimps, broken wires, weak battery and so on. How can a faulty head light connector cause this problem? It can cause an electrical short which will cause the ehc to go into fault mode and shut the system down to protect itself. Turning the key switch will reset it. The fault lights on the ehc will tell you which system to start looking at first. My situation with the faulty key switch is that it would break connection with ehc and the ehc would think I was shutting down the bike so I would not get a fault light on the ehc. Start with the simple things first especially the ground wire from the battery to the starter mount. Be sure to tell us what you find so others can learn from your situation.
 

Coolbreezin

Active Member
Thanks RRRUFF. I cked both battery connections and also ground to starter, all tight. Recently replaced headlight bulb, no wear or issues in shell. Replaced key switch less than a year ago. The key isnt loose inside switch like it was when it finally failed. Im removing the coil cover to get it painted this month so Ill be right there to ck for any problems. Still hoping to see the big flashing arrow though. lol

Yall take care and see ya in a couple mpnths in Daytona.
 

stlmikie

I wish I had more money.
Something else you might try is start the bike and start with the jiggle test. On all the wires you have access to. If you take that test on jiggle for 5-10 seconds each. Or longer if time doesn't matter. Cause the failure.
 
You said you replaced the headlight with a hid light thought i saw something about hid light affecting the electrical systems on our bikes. This may be a stretch but may want to check this out.
 

Coolbreezin

Active Member
Thanks Pauldeepsea, but this problem has been ongoing since April 2005 with the first ride. Plus my friend has a 2004 BDM chopper with the same headlight bulb and he has absolutely no issues.

Any others thoughts are welcome.
 

Wingnut922

New Member
Dead in the water

2004 Big Dog Chopper
Same problem as you and everyone else, pull your seat off and flip it over you will be looking for a mashed down area in yhe carpet under your seat. After numerous episodes I found that when my fat ass leaned to one side in a turn this problem would happen. my answer was to flip around the battery so that the terminals are closer to theto the back of the oil tank. You must be carefull not to allow the positive terminal to touch the oil tank mounts, I used a black closed cell foam 1/2 inch thick for padding around the battery for proper placement. The correct fix would be a shorter battery but that is easyer said than done, when the battery negative and positive are shorted for a moment this kills the ECU that is why it starts right back up. A the same time I was doing this repair I noticed that the power relay that is mounted on the fender was creating a rub mark in the carpet as well. I took everthing loose and rerouted the wiring along with the battery cables which are long enough for this fix you just have to loosen them at the starter and reposition them. I relocated the the power relay, the ignition box lower down under the seat and have not had any problems since. I will post a picture soon of the repair, it's like putting 5 pounds of crap in a 2 pound bag it just does not fit. Good luck.
 

pknowles

RETIRED
2004 Big Dog Chopper
Same problem as you and everyone else, pull your seat off and flip it over you will be looking for a mashed down area in yhe carpet under your seat. After numerous episodes I found that when my fat ass leaned to one side in a turn this problem would happen. my answer was to flip around the battery so that the terminals are closer to theto the back of the oil tank. You must be carefull not to allow the positive terminal to touch the oil tank mounts, I used a black closed cell foam 1/2 inch thick for padding around the battery for proper placement. The correct fix would be a shorter battery but that is easyer said than done, when the battery negative and positive are shorted for a moment this kills the ECU that is why it starts right back up. A the same time I was doing this repair I noticed that the power relay that is mounted on the fender was creating a rub mark in the carpet as well. I took everthing loose and rerouted the wiring along with the battery cables which are long enough for this fix you just have to loosen them at the starter and reposition them. I relocated the the power relay, the ignition box lower down under the seat and have not had any problems since. I will post a picture soon of the repair, it's like putting 5 pounds of crap in a 2 pound bag it just does not fit. Good luck.
Good info here. I'm one of the ones that changed probably before the ehc failed. If your battery arched out on the pan wouldn't you see some burn marks? Now I have to look under the seat for burned spots and dents.
 

Sven

Well-Known Member
A generic deal with this is a loose wire = I hit a bump and/or let it idle. Both those bang and pulses took out a wire. Why narrow it down to a 'possible wire?' My thinking is if it was heat related it would not start right back up. If it was a faulty sensor it would fry by now and no longer start. However, this more sounds like it's wire connector bounces off, acts the kill switch to main power, or to spark, or to cam/crank sensor(s).

You figure the black box is nothing more than waiting for an input signal to send the output signal. To me, it sounds like the box is fine. So, is there an input failure to the black box? Or, is there an output failure to the final jobber, meaning, spark or fuel? WATT you can't sort of do is cause a different resistance to the input signal. So technically, if this bike had a backup system for the sensor, you'd want to run a test light/ohm meter to the wire input side. Why? You are trying to follow to see if the input loses current?

On the output side, you want to see if the test light/meter loses signal to the coil or injector? If you think it's the EHC, then that output [wire] side of the box, [you want to question] that puppy. So in a sense, you are looking at 6 basic wire connections:

1. Power wire source from (+) side = Starts.
2. The (+) source to the hot side of the Key lug = Ends.
3. The wire from the lug of the key going out to the next jobber = Starts.
4. The jobber has received this wire from the output side of the key = Ends.
5. The wire out of the jobber is connected to harness/other jobber = Starts. 6. The final output wire [for that loop] then travels to ground = Ends the complete cycle to (-) ground.

A. Input Signal: Did you lose power to the key or box? So the timing light would be hooked to the spark plug lead. This shows output has dropped, so the input at the cam or crank sensor needs to fail = IF it is on the input side.

B. Key switch: Did you lose power here? So a test light will remain on the battery side of the switch. Another test light will come out of the output lug of the key switch. If power is lost on the battery side = Loose battery terminals/loose battery, etc. If the current stays lit on the battery side of the key switch, but now the output test light from the key switch is off w/key on, did you catch that? You turn the key off, turn it back on and the test light from the output lug comes back on = Key Switch sort of narrows it down.

C. Output Reference Signal: So in a way, it is more like narrowing down two variables, meaning; input/output. We could more or less bleed off of the cam/crank/power input side and see what current was lost between input or power loss. On the output side, it is more or less you watching the fuel injector lose output from the black box, or the timing light; as the plug drops out. This more or less says, if my lights stay on, the bike dies, it's ignition related. If the bike dies and all is lost, it is the input side.

Make sense in the chase of [way too many] variables to narrow down?
 

Wingnut922

New Member
Power loss to ech

Here are pictures of the repairs that I made. You can see the large spot under the seat from the battery, if you short 800 amps you are going to know it very fast but if you short 200 amps momentarily which is all it takes to kill the power to the ECH it could be over looked. I used high strength 3M body trim tape to attach the ignition module to the ECH for position and then moved the other components as you can see.
 

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