Intermittent Power Loss Puzzle | GTAMotorcycle.com

Intermittent Power Loss Puzzle

FattBoyy

Well-known member
Hello All

Hoping some one here can give me some ideas, I though I had this solved,, I was wrong,

Bike is a 1996 fatboy

Issue: intermittent loss of power,

Symptoms: analog speedo drops to zero, digital km counter turns off, bike bogs down like it's getting no fuel. (Guessing from plugs not firing). Loss of power , Lights dim in and out. However The bike does not shut off, I pull over let it idle a minute if that and it steadies itself.

This happened twice a few weeks back, I checked battery it has 12.5, when bike is running goes up to 14 if I give throttle.

I tightened everything going to battery and the main ground cable cleaned it all out. Rode the bike for 2 weeks no problem..

Today it happened again. And now I am guessing something In the fuel delivery causes power loss? Is that crazy?

Here is why.. Today I noticed, this happens I think not sure when I open up the throttle passed half.. It's almost like it bogs down from too much gas? But is that possible to shut off power,,

Is there any scenario where where giving throttle would cause power loss symptoms

Or

When I give it so much guess it shakes so much (and it does) then the loose electrical contact comes into affect? But then how does the connection steady itself back so quick

Any ideas?
 
Since you checked the battery connections / cables - a random guess is the ignition switch connections (under the console)
 
Hello All
I am guessing something In the fuel delivery causes power loss? Is that crazy?
Here is why.. Today I noticed, this happens I think not sure when I open up the throttle passed half.. It's almost like it bogs down from too much gas? But is that possible to shut off power,,

does your harley vibrate more at higher rpm,, or smooth out vibrations.......... [just read you stated it does..] so ,, I'd be looking for that loose connection.
FLSTC said Since you checked the battery connections / cables - a random guess is the ignition switch connections (under the console)

I'll add my R.A.G. .. random ***** guess... I just found my problem on sunday.. the PO had added some running lights by putting a scotchlok on the wiring.. which finally burned thru, and the circuit was intermittent while this was happening,,

alot of wiring is in behind the headlight .. pull it out and inspect there... it is pretty easy..
 
Since you checked the battery connections / cables - a random guess is the ignition switch connections (under the console)

When the issue happens I quickly turned the ignition switch on and off and it made no difference... So I am kind of leaning away from that
 
So if it is vibration at high rpm's loosening a bad connection, then why does the problem continue for 20-30 seconds after I am no longer in the high rpm's

That's my issue with that theory. I thought of the same thing
 
I was thinking about a corroded connection in the wires/plugs to the ignition switch, under the console. I read about this somewhere. The instant loss of voltage/signal to the speedo leads me in that direction.

Would a bad coil do this, probably not,

What about a bad stator (under or overvoltage) - don't think so.

Bad voltage regulator? Possibility.

Battery/cables? More likely hard/fail to start vs loss of voltage when running (stator/v-r providing voltage)
 
Ahhhh - is this the bike that you had to take the chrome cover off the triple tees? Could be something pinched up there...
 
No not that bike :)

I can check under the ignition..
Let's see if anyone else chimes in with any other ideas
 
If instruments are turning off / displaying zero or nothing, the problem is electrical in nature, not fuel delivery.

I had a wacky electrical problem on a fuel injected bike in which it would randomly lose power. It turned out that a cheap crappy license plate LED was shorting internally, but the extremely thin wiring to it would pull a lot of current but not enough to blow the fuse ... but enough to cause a voltage drop to the other electrical components that were fed from the same fuse box, and guess what, that included the EFI fuse. It was a bugger to figure that one out.
 
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If instruments are turning off / displaying zero or nothing, the problem is electrical in nature, not fuel delivery.

I had a wacky electrical problem on a fuel injected bike in which it would randomly lose power. It turned out that a cheap crappy license plate LED was shorting internally, but the extremely thin wiring to it would pull a lot of current but not enough to blow the fuse ... but enough to cause a voltage drop to the other electrical components that were fed from the same fuse box, and guess what, that included the EFI fuse. It was a bugger to figure that one out.

Ok so what's a good plan of attack to find this ?

It seems there is split second power loss over and over them I pull over idle for 30 seconds and its ussually fine.
 
Could be one of the connectors. Had a similar issue. Had to pull the plug out & tighten the connections
 
Could be one of the connectors. Had a similar issue. Had to pull the plug out & tighten the connections

Different bike, but I was having similar problem recently - seemed like fuel delivery, and it turned out it was. One of the wires had broken off of the female connector in the plug - seemed fine to look at it, until I pulled the plug away from the fuel pump relay and the wire popped out. It was intermittent, because the wire was sitting in the right place. In your case, it's got to be "further up the chain", or closer to the battery/ignition - because it affects all of your electrical accessories. Is the battery charging and holding a charge okay? Could it be the regulator?
 
Different bike, but I was having similar problem recently - seemed like fuel delivery, and it turned out it was. One of the wires had broken off of the female connector in the plug - seemed fine to look at it, until I pulled the plug away from the fuel pump relay and the wire popped out. It was intermittent, because the wire was sitting in the right place. In your case, it's got to be "further up the chain", or closer to the battery/ignition - because it affects all of your electrical accessories. Is the battery charging and holding a charge okay? Could it be the regulator?

Ok the battery shows 12.5 and 14.0 while running, is this a sufficient test if the battery and charging system?

I am guessing the running out of gas feeling comes from the spark plugs not firing at that instant right?
 
Just replaced the center console switch 2 weeks ago ( 07 Superglide ). It was intermittent to start with then turned into a full failure. Similar to what you are describing. I did figure out the problem before it failed ( sticky and when you played with it the bike would shut down). Too bad I didn't replace it before it failed on my Wife. Dam did I hear about that one
 
This I will do.
Is there a chance my battery is failing under heavier load of accelerating?

No. The demand on the battery once the bike is running is low, and non-existent when the bike is moving (e.g. battery is charging rather than discharging)
 
Just replaced the center console switch 2 weeks ago ( 07 Superglide ). It was intermittent to start with then turned into a full failure. Similar to what you are describing. I did figure out the problem before it failed ( sticky and when you played with it the bike would shut down). Too bad I didn't replace it before it failed on my Wife. Dam did I hear about that one

But when I fiddle with it. I don't get any symptoms. That why I am skeptical. I guess I won't know until I look
 
I just took the ignition switch out fiddled everything I don't think there is anything wrong there,, I did notice the negative terminal came off the battery with one twist so I am hoping it's the issue? I doubt it. Not that lucky
 

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