[[email protected]]

Has anyone ever had there engine quit and start again be itself? I was going down the freeway at approx. 70mph and the engine rpms went from about 7400 to 0 and back to 7400 in a split second. It then did it a second and third time after I started to go home. I then tried to replicate the problem myself. So, I kicked her back up to 70 and again she quit but as she coasted down to 65 she started right back on her own.

So it seems she wants to quite at 70 mph and will restart at 65 mph. It is electrical as it was like a switch was tripped. I have the little code tool that I hook up to display the codes and will get to that in a day or so. But any thoughts?

Mike

 

[Jim]

Sounds like a possible fuel or air issue, like it's starving.

Possible very dirty air filter, or fuel filter.

Also possibly spark plug.

 

[Buffalo]

Something else to check is the throttle position sensor.

 

[itlives]

Caveat- I don't know what I'm talking about. But that never stopped me before.

I don't know if electronic ignition is the same on cars and motorcycles but my electronic ignition control module did that on my Ford.
Yours is displaying the exact same symptoms. I replaced it and never had the problem again.

 

[mikeyMarine]

Caveat- I don't know what I'm talking about. But that never stopped me before.

I don't know if electronic ignition is the same on cars and motorcycles but my electronic ignition control module did that on my Ford.
Yours is displaying the exact same symptoms. I replaced it and never had the problem again.

yup I'm thinkin this is a computer problem, now is it doing what it's told or is it getting erroneous shutdown signals from somewhere

 

[Redbeard]

Also check the side stand switch.

 

[[email protected]]

Thanks guys for the suggestions. I am going to run some more tests on her and I will try out some of these scenarios. I will report back as to what the mechs say.

Mike

p.s. I hope it is not a control module-something tells me $$$$ at that point.

 

[Colchicine]

One other thing to consider- the shut off switch on the right handlebar cluster. You can make the bike do this manually by flipping that switch at high speeds. It will auto fire to normal as soon as you switch it back to on. Perhaps the switch has gotten dirt/water in it, and it's a lot easier to check than the other components suggested.

 

[[email protected]]

Ok gang here is what I did. I changed out the air filter and spark plug-mainly because they needed it anyways. I took her for a test drive and-nothing. She ran like a top. I took her through the speed range that 'caused' the cut out to happen and nothing. So I am 'guessing' the plug was shorting out as it happened so quickly it had to have been electrical. Thank you all for the replys and help.

Mike

 

[NormanB]

From the described symptoms and behaviour - I would not be so confident that the matter is resolved .....so soon.

 

[[email protected]]

NormanB, I am hoping I will still plug in the code switch to see if anything pops up. But here is to hoping. Buy the way where is the throttle sensor?

Mike

 

[Ralph M]

Sounds like the electrics are being disconnected look for any loose connections start with the battery does the ignition switch seem ok.

 

[Buffalo]

Buy the way where is the throttle sensor?

Mike

The TPS sensor is located on the throttle body on the end of the shaft opposite the side with the linkage on it. You don't test it at the sensor though. You test it at the plug where it hooks to the wire harness. According to the manual that plug can be accessed by removing the left leg shield.

 

[Colchicine]

^I agree.

And it's not really possible for an engine to be running and having a spark plug short. Much less begin running normally immediately.

 

[TheDarkCutlass]

If its still acting up after your fixes. Take a look at the fuel filter. Had a car many years ago that had similar symptoms at high speed. It was starving for fuel due to what I'm assuming was a bad batch of gas that gummed the filter all up.

 

[[email protected]]

NormanB...you were right. It did it again on Monday and i got the dreaded FI light today. So I will tear into her tomorrow.

Mike

 

[[email protected]]

Well I put the code switch on her and I got a brief c15 which is engine temp coolant switch, but that went away and never returned. Then I got a _c00 code which is the Throttle Sensor which I adjusted back to the normal position.

I started it up and got an FI light, shut her down and started again an nothing. So I took her out for a test run and she ran fine. Then she did it again. So I am off to put the code switch back on her.

If I have the same code as before then I know the TPS switch is either bad or dirty or it moved on me after I adjusted it. If no error code then I may dive into the tank to see about the fuel filter.

Mike

 

[SteveE]

Having the engine suddenly cut out and just as suddenly restart can be a symptom of a failing ignition switch. That's what would happen to my 650 before I had to replace the ignition switch TWICE in two years! Don't know if the iginition switch design is the same for both bikes, but on the 650 virtually all of the operating current load flows thru the switch which can/will overheat and eventually fail. This is especially true if you draw any significant power from the aux power jack or if you run your high beams a lot. I was guilty of both. Now on my third switch I have installed a high current 40A relay to handle the operating current load and the only load the ignition switch now "sees" is the miniscule load of the relay actuation coil.

 

[[email protected]]

O.K. I started looking around the bike today and noticed the coil wire looked frayed so I took it out to have a look at it. The wire looks good, it was just the angle and light made it look worse than it is. When I pulled the leads off they were covered in oil as my airbox leaks right above them. So I cleaned them off and was hoping that was the problem. Yeah! reinstall and test drive.

Well, I went to reinstall the leads and noticed that I have a wire going a direction that the other was not not. One of the wires to the Coolant sensor sheared right at the sensor. What would explain the code that I got initially about the Coolant temp sensor. But it went away so I did not think about it after that. Is it possible that the computer senses an open circuit and shuts off but then gets signal again and restarts?

Mike

 

[Ralph M]

It's entirely possible that the ECU is getting all sorts of strange signals from the
temp sensor and is shutting the engine down to save the engine, any way it's got
to be worth sorting it out then trying the scooter again, if it's getting signals that
the engine is cold then it could be richening the mix to the point of a rich cut or
if a sig that things are overheating then it may be shutting the engine down.