| Author | Message | ||
     Fightnphoto |
Good day folks, I'm working on the girlfriends 2003 XB9sl. it started leaking oil pretty bad from the lower rear base gasket but ran great. I pulled the motor and fixed the leak but now it won't start. it turns over and has fuel but seems to be short on spark. I've tested the wires coming and have power to the coil and the CPS is brand new so i'm a bit lost. can an ECM just go bad sitting? The battery was disconnected through all the work so there should have been no big shocks. Can the TPS be that far out just by removing the engine? any advice would be great. Cheers. | ||
| Blake |
Ensure grounding. Service manual has excellent diagnostic procedure for no spark. I can shoot a copy later from my 2009 XB manual if you need. If the CPS is new, that circuit might be a good place to start, no pun intended. Check mounting and connections. Check to see if the coil is getting the low voltage input signal. If not, then CPS circuit is likely culprit, especially since it was recently worked on. | ||
| Reepicheep |
How long did it sit? Maybe fresh gas and fresh plugs are all it needs. You can check the actual cps signal by watching the tach when you crank the motor with the starter (or even better with a $70 oscilloscope). | ||
| Fightnphoto |
Thanks guys. I rebuilt the top end gaskets. Bike ran great prior to removal. I pinned out all the wires and there is power to the coil but no signal. I'm on second CPS thinking it was the culprit. Last night I tested the signal from CPS all the way to the computer and it's good. From computer to coil the wires check ok but no signal. Why would an ECM go bad if nothing touched it? I was hoping maybe someone would have had the same issues at some point. Right now I'm thinking ECM but is there a way to test it? | ||
| Reepicheep |
The ECM can definitely "break", either at the wiring harness, or the solder pads where the connectors go into the ECM motherboard. The aren't well supported, and the routing makes it easy to load up the wires, which loads up the connectors, which cracks the solder joints. It is usually purely mechanical breakage, so you might see it come and go if you wiggle the connector. That could be a dead giveaway. The wiring bundle under the front steering head can chafe / crack also, and when you rotated the engine to do the gasket, you might have changed a "broken but touching" wire into a "broken but open" wire. They crack inside the insulation, not outside, so you can feel it but not see it. | ||
| Reepicheep |
Oh, and this is a 9s. Also look at where the ECM wire bundle routes relative to the sharp edge of the battery cable. If it goes over it, you can get a microscopic nick and short some random wire to that battery terminal, which can do some random odd thing. You have to route it and the battery terminal so that sharp edge doesn't touch anything. | ||
| Fightnphoto |
Thanks for the suggestions. Just looked at the routing and everything looks good. I also checked continuity between the coil and computer blk/rd and yw/gn. Both read good. I get the test light out again and tried ground all over the bike and it seems to be strong. Is there specific locations I should check? | ||
| Fightnphoto |
Ok. So got the bike fixed and running. Turns out I'm an idiot. CPS plug is the same as one of the other plugs just a different color. Make sure the gray plugs go together and the black plugs go together. I feel shame. Thanks for the help and suggestions. Hope I save someone else the issue. Cheers | ||
| Reepicheep |
Hey, a mistake is a mistake. If anyone thinks they can do repairs and never make one, they are a fool in denial. The rest of us are just fools. You went to fix your bike. You fixed your bike. All the in between parts aren't relevant. The stories I could tell on myself...  Thanks for the heads up! So what was the other connector over there... neutral indicator probably? That will be a great tip we can use later to sound like geniuses when somebody else does that. Somebody tells us they have no spark after working on the right side of the motor, and we cooly ask them to go see if their neutral indicator works. | ||
| Fightnphoto |
So the plugs are cps and speed sensor.identical plugs just different colors. I feel better now that it runs again. Not my first mistake... Probably not the last. Cheers |
