| Author | Message | ||
     Chadhargis |
Some of you may recall that a few weeks ago I posted about my exhaust servo cycling. It never did it again until tonight. Here's the scoop: 1) I had not ridden the bike in about 3 weeks, but it had been kept on a battery tender in my garage. 2) I turned the ignition key on with the engine cut off switch in the off position, and the servo began cycling, the low fuel light came on and stayed on, and the odometer switched to the "F" setting (I had a full tank of fuel). 3) I flipped the engine cut of switch to the run position, and the cycling stopped, the low fuel light went out, and after diagnostics completed, the check engine light went out as normal. The bike started and ran flawlessly. No check engine light, no exhaust cycling. Fuel light stayed out. 4) When I got back home from my ride, I tried turning the key on with the engine cut off switch in the off position. Same result. I flipped the switch to the run position and it was fine. 5) I turned the key off, left the engine cut off switch in the run position, held the throttle wide open, and turned on the key. The servo cycled once as per the service manual. 6) I removed the airbox and watched the servo cycling for several minutes. It would go wide open, and then partially closed. However, if I did the servo check as per the manual by holding the throttle wide open and turning the key on with the engine cut off switch in the run position, it would open completely and close completely just as it should. 7) I disconnected the battery and reconnected it. No change. 8) I hooked up the Techno Research cable and used the software to reset any diagnostic codes. No change. 9) I unhooked the servo and turned on the key with the engine cut off switch in the run position and got an error indicated by the check engine light (as expected). 10) I hooked the servo back up....same results as before. So...any of you Buell experts out there have a clue as to what's going on? My bike didn't do this before, and only once before today. Now it's repeatable on demand. What would make the servo cycle and the low fuel light come on with the engine cut off switch in the off position? Maybe I should get get the Race Kit and be done with the servo. If I wasn't so fearful of loosing bottom end torque, I'd pull the trigger on the race kit. Seems like the exhaust server is nothing but a pain in the butt. | ||
| Opto |
The servo motor assy is cactus, the fuel light might be another issue. Or, your ecm has lost the plot. Have you been messing around with any ground wires at all? A good servo motor with a good ecm only has 2 positions, open or closed. | ||
| Chadhargis |
Nope...no wire tomfoolery. | ||
| Clayman |
Just my 2 sents but ive got the drummer and no servo, ive removed the cable to the exhaust and the bike runs great with no more servo problems. Before this i had to have the servo replaced in the first week of owning the bike, and then the new one started acting up a month later. All is well now. | ||
| Stevenknapp |
Chad, the issue with the fuel light as well as the servo has me thinking ground issue. I'll look at the wiring diagram tonight, I'm curious what might be common. As before, I'd also get the DVM out, and look at the output signal from the ECU that controls the servo. See what it's doing. Then also, for grins, look at the feedback back from the servo. Use the servo connectors ground pin as well as try it with the battery - as the ground. | ||
| Stevenknapp |
I don't have a bike to look at, but the service manual for this bike is pretty good. If I was a betting man I'd guess that you've got a loose ground. Further, I think the fuel setup and the servo share a ground. From the looks of it, in the knee of the "L" made by the fuse box and the ECU. The other way to go is to follow the exhaust servo wiring. There is a four pin plug on the servo. Black is ground. But there is another 3-pin connector into the main harness. No ground on this connector. The black wire grounds to the frame. If you wanted to prove a theory, put your DVM on the black/ground pin of the exhaust box, and the other end on the battery's "-" terminal. Set it to volts and go nutz. Why is this? I'm not sure. Maybe something else is using that ground path when the kill switch is "off" causing the voltage to increase? Anyways, a place to start. | ||
| Chadhargis |
Thanks for the advice. I'll do some fiddling with it tonight and see what I can see. |
