Bike fires and starts then immediately dies.

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I have just tried to do the relay, solenoid and injector diagnostic test. I turn the kill switch off and on and noting happens, no engine trouble light and no relay clicks.

When I turn the bike on normally (not in diagnostic mode) fuel relay actuates.

I am going to check the kill switch again.

 
Sometimes it is the simple things. Fingers crossed!

It could be grime in the switch. You might try disassembling the switch housing and spraying some contact cleaner in there.

 
Unlike some bikes, the FJR's starter won't run with the kill switch tripped. If the starter runs I don't think it's the kill switch.

European system might be different, though. . . .

 
Last edited by a moderator:
I have just tried to do the relay, solenoid and injector diagnostic test. I turn the kill switch off and on and noting happens, no engine trouble light and no relay clicks.

When I turn the bike on normally (not in diagnostic mode) fuel relay actuates.

I am going to check the kill switch again.
All of the symptoms you list from the diagnostic test are consistent with the the Fuel Injection Relay not being turned on by the ECU. You say that with normal key operation the fuel relay turns on, are you sure it is the fuel relay and not another relay? Do you hear the fuel pump turn on and run for 3-5 seconds when you turn the key on? Are you able to test the fuel pressure on the fuel rail?

It is troubling that you can't turn on the Fuel Injection Relay via the diagnostic procedure, this indicates that the ECU can't turn the relay on for some reason. It does fit the symptoms when:

-- the fuel pump runs when the key is turned on

-- fuel is then delivered to the fuel rail

-- the motorcycle starts and consumes the fuel in the fuel rail

-- the ECU can not turn on the Fuel Injection Relay so after the fuel in the rail is consumed the engine dies

This is why I ask if you can test or monitor fuel pressure on the fuel rail.

Did you find any errors stored in memory when you ran the diagnostics?

 
Last edited by a moderator:
The kill switch is good unfortunately. The fuel relay actuates when I cycle the diagnostics to 09, but not in the 50 option and there are no stored errors. I don’t have the facility to monitor the fuel pressure but I will as around and see if I can find someone who can.

Ionbeam, what you say sounds just right I thought a new ECU may be on the cards.

However, things have just gone from frustrating to bizarre.

I took the tank off and checked the fuel pump connections and voltage. On turning the engine over I get a good voltage at the pump. Having put the tank back on, I gave the bike another try. It started and ran for a good time! Feeling very happy with myself (despite having no idea how I managed to get the thing to run) I turned the key off, the engine stopped but the starter motor started turning the engine over and would not stop. I hit the kill switch, cycled the key and removed the main fuse, no joy the motor kept turning over. I finally disconnected the battery and the starter motor stopped (obviously). I removed the battery and checked the start relay, it was still engaged. I can only assume the relay latched and remained latched even without the battery. Could a faulty start relay be causing all of my problems?

 
It sounds like you may have to separate problems.

I still think you chould consider unplugging the main ECU connection and re-plugging, just in case you have a corroded connection or two. A little dilectric grease isn't a bad thought, either, as you locale is probably more harseh than mine.

 
Now it's sounding like a wiring problem. The starter relay being stuck could be the starter switch sticking, even.

03HiYoSilver's been through some electrical weirdness he tracked down to a main connector just inside the frame under the front of the tank. Don't know for sure that the same connector exists on the European bike.

The thing about a harness connector problem is that the connector carries several circuits, so the bike exhibits several seemingly unrelated problems. Sound familiar?

 
Last edited by a moderator:
After many hours studying wiring diagrams and testing with a multimeter it lives!!!! I changed the start relay and we have a runner. The start relay also supplies power to the fuel pump and injectors via the fuel injection system relay. Without the positive supply from the battery to the fuel pump and injectors, the machine would not run. As it turns out the positive supply through those relays also feeds the ECU with the power to run diagnostic testing of the light, injector, start, fuel injection, and radiator fan, relays. The diagnostic system now runs correctly and the bike runs.

Thanks for all of your help and suggestions.

One more thing, how do I up load the diagram of what I did?

Cheers,

TAZ

 
:clapping: :yahoo: :clapping: :yahoo:

Congratulations on the repair and on posting your results here.

Posting a diagram is like posting a picture. It must be hosted on another site (Picasa, photobucket, etc.) and then linked using the photo icon, 2 spaces to the right of the smiley icon, under "sizes", just above this area when posting.

 
Top