Engine cuts out on bumps

[IG.]

Running out of ideas - need a little help.

Symptom: momentary loss of power over bigger bumps, smaller bumps are OK. No FI light ever when this happens (i.e. no code).

Recent work: had C24 problem on starting the bike - cured by cleaning coil connectors - never shows up after the fix.

Troubleshooting done:

1. Shorted the kickstand switch. Rode. Still a problem.

2. Put the bike on rear stand, lifted the tank, started, put in 1st gear. Pulled and banged on PC, ECM, battery, all connectors surrouning them, connectors under the tank (i.e. fuel pump connector, connector to injectors). Not a hiccup. I will repeat this exercise again, just to make sure.

What else? Connector to the instrument cluster, sidestand relay, kill switch, TO sensor. Not sure...

 

[dadofthree]

Could be a weal relay or you could just lay off the bumps. As aggravating as this is you just can't fix something until it's broke. Unlike dealerships you can't start swapping out parts to get a fix. So typically you have to wait until it either fixes itself or breaks.

I feel for ya, good luck with it.

Add battery connections and ground connections.....

 

[dadofthree]

All connections are suspect at this point, including fuses. Has the harness ever been damaged ?

 

[IG.]

All connections are suspect at this point, including fuses. Has the harness ever been damaged ?

Nope.

 

[Powers739]

For some reason I am going with the killswitch.

But, I'm lazy and I would start with the easiest of the above you mentioned and start the process of elimination.

Let us know waht you find.

 

[Tufbusa]

Check your battery ground wire, oposite end of the battery. Maybe remove, clean and re-attach.

Disconnect the PC altogether.

 

[racerV]

Look at the tip over sensor. It is mounted with the same bolt that holds the back of your gas tank. It may be bad or the mount may be broken. It is a brass colored metal box with a bracket attached to it.

 

[IG.]

OK. I will give another shot at the "pull and shake while the bike is running" approach, and leave more heavy duty stuff for the weekend.

Let me ask you another question. If I leave the bike idling (as opposed to being in 1st gear) and will continue with my previous experiment, if I manage to disturb a bad connection it should shut down the bike, right? I already eliminated the kickstand switch. So, a bad connection anywhere else (kill switch, relay, fuses, wiring, PC, ECM, ground, TO sensor) should cause the bike to shut down or at least stumble even if the bike is in neutral and not in gear. Right?

 

[tclause]

Electrical gremlin, wiggle tug and tap any thing that looks suspect. Good Luck

 

[DEMMYM]

You might want to zip tie your Kickstand up tight against the safety switch, and see what happens, it could just be the kickstand is loose and bouncing off the switch, easy enough to check.

 

[Narcissus]

Also check or just replace all the vacuum lines. You've got an '01. If they're stock, it's time to replace them.

 

[dadofthree]

OK. I will give another shot at the "pull and shake while the bike is running" approach, and leave more heavy duty stuff for the weekend.

Let me ask you another question. If I leave the bike idling (as opposed to being in 1st gear) and will continue with my previous experiment, if I manage to disturb a bad connection it should shut down the bike, right? I already eliminated the kickstand switch. So, a bad connection anywhere else (kill switch, relay, fuses, wiring, PC, ECM, ground, TO sensor) should cause the bike to shut down or at least stumble even if the bike is in neutral and not in gear. Right?

right

 

[IG.]

The kickstand switch has been disconnected all this time - so that's not a problem. Vacuum lines look good - I inspected them, and they certainly wouldn't cause a momentary loss of power over the bump.

 

[racerV]

I still think it's the TO sensor and it is easy to inspect.

 

[owens231]

I had the same problem with my aprilia...
turns out, raising the front of the tank 1inch did the job
somthing to do with when the fuels low the tank is better off in a relaxed possition...

only cost £5 for washers too!!

 

[IG.]

I still think it's the TO sensor and it is easy to inspect.

Inspected. It's mounted solid. I will bang on it when I have a chance to start the engine and let her idle. If all else fail, I will unscrew the sucker and shake it while the engine is idling.

 

[IG.]

I had the same problem with my aprilia...
turns out, raising the front of the tank 1inch did the job
somthing to do with when the fuels low the tank is better off in a relaxed possition...

only cost £5 for washers too!!

did the same thing when the tank was full. Doesn't seem to be fuel related.

 

[owens231]

Ohh rite, okay im stuck, i have looked on the internet at answers from people with the same question, 1 guy from "texus" said...

I have taken it to 3 garages for them to find out the problem, no1 knows...
But then it came to me, there is a valve in the tank that turns fuel on and off, and just above that, theres a measure gage, if that is pushed down, the preasure increases...

Apart from when u open it up to full her up again...

His was a gen1 1999 busa...

I dont know the answer to that myself but try that out...

 

[Acehole]

Ignition switch?

 

[IG.]

Ohh rite, okay im stuck, i have looked on the internet at answers from people with the same question, 1 guy from "texus" said...

I have taken it to 3 garages for them to find out the problem, no1 knows...
But then it came to me, there is a valve in the tank that turns fuel on and off, and just above that, theres a measure gage, if that is pushed down, the preasure increases...

Apart from when u open it up to full her up again...

His was a gen1 1999 busa...

I dont know the answer to that myself but try that out...

Umm.. Thanks for the details. But you lost me there... In any event, a fuel cut off for a second would in the worst case make the bike to stutter, cough, etc. First, why whould it happen on the bump. Second, my cut off is absolutely clean - OFF, and a moment later ON - no sputtering, hesitation, etc.