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Discussion Starter #1
I'll try to make this as clear as possible...


The other day, the bike ('01 RC, full Ack exhaust + flapper mod) cut out a couple of times under hard accel. Both times it happened in second, around 8K or so. This was like a hard hiccup, the bike lurched hard and then accelerated normally through all the other gears. This happened twice that day.

Later that night, the bike started stuttering and bucking badly, the cluster flickered, and the FI light blinked on and off, and the bike stalled a couple of times.
I turned around and headed home, and as I was cruising at a steady pace on the highway, the bike started stuttering and lurching again, FI light blinking again, and stalled again, cluster still on. I started it back up and road for a short distance, the bike stuttered and lurched, and then lost ALL electrical power and died completely.

I had the bike towed home since I was in the middle of the interstate about ten miles from home.
The next day I checked connections at the battery and they were solid.
Then I tapped on the ECU itself, and the power came back on. I checked battery voltage, and it showed 12+ volts. The bike fired right up.

I then removed each of the pin connectors from the ECU and checked each pin to see if one or more of them was loose, they were all solid.
I plugged the ECU back in and with the key switched to "ON" I wiggled each wire connected to the ECU and watched the cluster to see if it would flicker, indicating a loose connection. All the wires were solid.
(I just bought this bike, the previous owner installed the undertail, and did not fasten anything down correctly inside, including the ECU and taillight assembly)

I decided to ride the bike a short distance down to the beach to see how it would act. Just as I got there it started sputtering and bucking again.
I took the pillion cowl off and tapped on the ECU again, the juice came back on.
This time when I tried to start it, I heard what sounded like a circuit breaker opening (*click*) and the power went out. Each time I tapped on the ECU, I got the power back, but would lose it again when I tried to start it.
Finally I got it to stay running again, and was able to get the bike home.

Are there any circuit breakers back there that would open the main circuit? Whatever is opening seems to be inside the ECU, since tapping on each of the relays (?) back there did nothing. Could there be a circuit breaker inside the ECU for some reason?

Can somebody post a wiring diagram?
Any ideas?
 

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Have you checked your main ground on the right hand side of the bike near the subframe bolts. I had a similar problem, I didnt have good contact on the main ground there.
 

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FI light means you might have some codes to retrieve. Tapping on that ECU could be causing just enough vibration to the bike itself to get whatever is acting up to right itself, making you think the ECU is bad when it might not be. Search for the code pulling process and find out what code number it is. That will point you in the precise direction:) Chances are good the vibration from riding and bumps is causing a loose connection to act up.
 

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Discussion Starter #4
topturtle said:
Have you checked your main ground on the right hand side of the bike near the subframe bolts. I had a similar problem, I didnt have good contact on the main ground there.
If you mean the one grounded to the back of the case, no it's still solid. :(

area51racer said:
Tapping on that ECU could be causing just enough vibration to the bike itself to get whatever is acting up to right itself, making you think the ECU is bad when it might not be. Search for the code pulling process and find out what code number it is. That will point you in the precise direction:) Chances are good the vibration from riding and bumps is causing a loose connection to act up.
That's what I thought at first, so I tried bumping the bike in several different places with the bike running and with key-on-engine-off, and nothing worked. I pounded on the seat, the pillion, the tank, the tree, tapped each of those relay-looking things in the tail individually... Only tapping on the ECU itself does it.

Where do I find the code retreval process? I have a .pdf manual but it's missing a few sections including the wiring diagrams :mad:
 

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no there is a main ground near the subframe mount bolts on the right side. if its loose or has a bad connection it will give all the problems you are describing, including the FI light to come on. Look for green wires connecting to the frame there. Not the main battery ground its the ground for your wire harness.
 

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Discussion Starter #6
topturtle said:
no there is a main ground near the subframe mount bolts on the right side. if its loose or has a bad connection it will give all the problems you are describing, including the FI light to come on. Look for green wires connecting to the frame there. Not the main battery ground its the ground for your wire harness.
Just checked it, that one's solid too. I'm gonna try retreiving the codes now.
Will it store those to memory even if it's not a hard fault? Or is it a hard fault even though the FI light's not always on?
 

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Discussion Starter #7
By "green clip" they mean the huge 20-pin green connector with the cap on it, right?
If so, which pins do I jump???

If not, what does the connector look like?
 

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Discussion Starter #8 (Edited)
Ok, I think I fixed it.

As I was in there poking around, I noticed a spark coming from the battery box. It was the battery positive terminal arcing :banghead I guess it was a loose battery connection after all. I must not have jigged that one hard enough.

So anyway, the pos terminal was now hot as a b**ch from arcing over and over again. After I tightened it down, I bumped the starter a bunch of times to see if it would open the circuit like it had been doing intermittently before, and it didn't, but the positive terminal started getting hot again as I did that. I guess that's just from full-fielding the coil over and over again???
Any thoughts on that?

UPDATE:
It was the batt + connection :eek:
fixed it.

thanks
 
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