| Author | Message | ||
     Xbimmer |
My tach is starting to act up more frequently now. It sweeps fine at key-on but when the engine catches the needle sometimes jumps up to 2-3k a couple of times, then settles to 1k at idle speed where it will sometimes jump up to around 2k. Rolling on the throttle it either moves with the engine speed or doesn't, then jumps up to eventually settle to actual rpms. Riding down the road everything acts pretty much normally, except for an occasional blip or bounce. Before I take it to the dealer for another warranty claim where I'll have to sit around for hours so they can tell me my tach is misbehaving, I was hoping it might be something simple. Everything else on the panel seems fine, including the low-fuel light which keeps coming on due to a faulty fuel pump I'm getting replaced soon. | ||
| Chris_socal |
Man, that stinks. I am assuming that the tach is electronically driven based on the fact that it sweeps as a part of a POST. Have you checked the cable between the module that senses the speed and the tach itself? Or is the ECM in line? Damn, I need to buy a service manual. This is like shooting in the dark. I am gonna go look at my bike to see what the deal is. -Chris | ||
| Xbimmer |
Yeah Chris you should get the OSM. I think all '08 XB's are included in one book, my '06 OSM is Uly-specific, I like the '08 idea better. Although the manual sometimes includes unnecessary steps in a procedure, and is sometimes flat out wrong, it's generally very good and informative. The wiring diagrams are excellent IMO. From what I can tell there is no rpm sensor directly to the tach, that was my first suspicion. I ignorantly suspect that the tach signals are sent from the ECM based on other info received say from the timing sensor which counts engine revolutions? Hell I don't know, just guessing. Think I'll check the main connector to the instruments this w/e, maybe by some freak chance the connectors to the tach could be loose while the rest are fine. | ||
| Chris_socal |
I know that some tachs work off of counting the number of times a particular plug wire fires, which is measuring the revolutions of the distributor. I am venturing a guess, but if the Buells have electronic distributors then there may be a wire that leaves that and heads up to the tach or ECM. Damn I need a service / wiring manual. Yep definitely... definitely need the manuals... not wearing any underwear... nope, definitely not... Kmart sucks, Wal Mart's better. Sorry went rainman for a moment. All better now. -Chris  | ||
| Teeps |
Hey Xbimmer, From your description; I doubt the problem is caused by wiring or connections. The Tach and Speedo needle movement are probably controlled by stepper motors, as opposed to a dual bobbin (opposing magnetic) type movement. Some times the logic circuits get scared or confused. In this case powering down and draining any capacitors will sometimes fix the problem. So, try doing a battery cable reset. It's free and the only down side is you will lose trip mileage and the clock will have to be reset. Start with Ig switch off * disconnect the negative battery cable * disconnect the positive battery cable * connect the two cables together. leave them connected for 5 minutes. * reconnect the positive cable. * reconnect the negative cable. start engine and see if the problem is fixed. | ||
| Xbimmer |
Thanks for the tip, Teeps. I tried it this week but it didn't help. Looks like another warranty issue, better now than a month from now... | ||
| Xbimmer |
Seems to be ambient temperature related. It's in the 80's here today, bike was pinging away and the tach needle was all over the scale. Sometimes at 3500 it would drop to 0 for a few moments, or accelerating it would shoot to 5000-6000 then crash back down, or blip at idle to 2-3000... all while the engine was running normally. Oh well. When I get it fixed I'll post the findings. | ||
| Ulendo |
know anyone with the most recent version of ECMSpy? in the diagnostics, theres a tach test mode - might help you isolate the problem to the gauge cluster/feed wire vs a sensor or input problem. (to say nothing of checking for error codes ) |
