No spark

[user 89005]

So there I was on a cold wet morning...and the girl just won't start.

No error codes, no diagnostic results indicating a problem.

Guages and dash lights are normal when ignition switch is on. Starter turns. Injectors function. Engine noises are normal, but she cranks til the battery dies.

Battery, plugs, and ignition switch are all new.

Used the maintenance manual to troubleshoot the ignition system. Switches and sensors are good. Wiring harness at the ECU has connectivity with the coils. Visually confirmed no spark in any of the plugs. Manual says replace the ECU.

Ouch, $900.

Before I blow the dollars, is there another way to confirm an ECU failure? Tried to detect a low voltage signal from ECU to coils when attempting to start the bike, got nothing.

What could have caused the failure before I plug a new ECU in I suspect I should fix the root cause. Note, my clock and trip odo resets occasionally and i have warped plastic at the upper right corner of the digital dash readout. No indicators of a burn on the electronic panel inside the dash.

Haven't seen but one FJR around and the Yamaha shop has nice folks, but their labor and parts costs are astronomical!

Appreciate and guidance or counsel...

 

[Denver_FJR]

What about the "other side" of the coil. Shouldn't it be getting 12v?

Check the ignition fuse?

If it comes down to ECU replacement (and I doubt it's gone south) would think there would be plenty on eBay.

 

[escapefjrtist]

<<Big Snippage>>Battery, plugs, and ignition switch are all new.
Note, my clock and trip odo resets occasionally and i have warped plastic at the upper right corner of the digital dash readout. No indicators of a burn on the electronic panel inside the dash.

I realize you say the battery is new, but a clock/odo reset is classic low voltage. Are you 100% confident the battery cables and grounds are tight...if yes, check them again. If the connections are tight, I'd buy/beg/borrow another known good battery to try.

GEN I's also have a couple large connectors near the steering head. Check those for signs of corrosion.

Lastly, are you sure it's not flooded? FJRs are sometimes a bitch to clear and get running after a non start episode.

You'll get a lot of great information here. Good luck!

--G

 

[Mihalis fjr]

Welcome.

Your new ignition switch is original spare part?You bought it from a Yamaha dealer?

Also i have never heard for a defective ECU in fjr..

I don't think that your ECU is bad.

Check all the connectors especially near the steering head as mentioned before.

Also,you said:''Note, my clock and trip odo resets occasionally''This is a bad battery sign..Or something takes all the power from the battery and don't leaves power for the ignition,so for that reason the reset in the clock and trip odo.A short circuit somewhere perhaps.

 

[Donal]

Have you used the diagnostic system to actually function test the coils?

Doctor Ionbeam's guide is here, diagnostic codes 30 & 31.

As I understand it the ECU grounds the coils, then isolates to produce a spark. Have you tried disconnecting the wire(s) from the coil to the ECU (at the coil) and doing this manually?

Seems odd to me that both coils would go out together......... I think I am with Denver_FJR on this. Confirm you have 12 volts at the 'other' side of the coil.

 

[Fred W]

The wasted spark design puts two coils in series. You need to keep that in mind when testing for a spark.

I'd be trying the Fast Starter Syndrome startup routine first.

 

[Big Sky]

"...and i have warped plastic at the upper right corner of the digital dash readout. No indicators of a burn on the electronic panel inside the dash."

I don't see where you state the year or Gen, but I'm guessing it's a Gen I. I had the Yamaha (AHAMAY) touring windscreen on my '03 and also had some meltage on the upper right part of the dash panel, actually melted entirely through the black plastic in one small spot. I thought something underneath must have gotten very hot. But it was later confirmed that if that touring screen was left in an upper position and the bike parked at just the right angle to the sun, like a magnifying glass there could be a hot spot, hot enough to melt dash plastic. There were several instances of this recorded here many years ago.

 

[Denver_FJR]

...Used the maintenance manual to troubleshoot the ignition system. Switches and sensors are good. Wiring harness at the ECU has connectivity with the coils. Visually confirmed no spark in any of the plugs. Manual says replace the ECU.

...

No spark is key!

I've had the fast starter problem before and diagnostic mode would still fire the plugs. ECU could be a problem but there have been many more issues with wiring and switches. I would work the circuits between coil and battery first. I don't have a Gen1, but there are several switches, relays and connectors I would check before digging into ECU.

 

[user 89005]

Great gouge guys!

Bottom line, long weekend ahead chasing the wiring diagram, connectors and ground, then use diagnostic again especially on #30 and 31.

In reference to all your great comments:

Yes, she's a Gen I FJR, 2003, 82k miles. I have two electronic accessories, one for a heated jacket (no, for my wife!) and one for PIAA halogen lights.

Confirmed coils are good.

Ignition fuse double checked as good.

Battery is good.

Compression seems good, can feel pressure at spark plug port.

Ignition switch is OEM new three years ago, checks good.

Warped plastic, ha, yes it's the sun magnified through my large touring wind screen!

Thanks again!

 

[wnyfjr]

I'm always one to ask about the stupid things that most everyone checks the very first thing...kill switch by chance? Prolly not, but I had to ask. Carry on and good luck!!

 

[RossKean]

I'm always one to ask about the stupid things that most everyone checks the very first thing...kill switch by chance? Prolly not, but I had to ask. Carry on and good luck!!

Won't turn over with kill switch on.

 

[Denver_FJR]

Great gouge guys!Bottom line, long weekend ahead chasing the wiring diagram, connectors and ground, then use diagnostic again especially on #30 and 31.

In reference to all your great comments:

Yes, she's a Gen I FJR, 2003, 82k miles. I have two electronic accessories, one for a heated jacket (no, for my wife!) and one for PIAA halogen lights.

Confirmed coils are good.

Ignition fuse double checked as good.

Battery is good.

Compression seems good, can feel pressure at spark plug port.

Ignition switch is OEM new three years ago, checks good.

Warped plastic, ha, yes it's the sun magnified through my large touring wind screen!

Thanks again!

Ok, but is there voltage at the coil? If there is,next test is ECU.

 

[wnyfjr]

I'm always one to ask about the stupid things that most everyone checks the very first thing...kill switch by chance? Prolly not, but I had to ask. Carry on and good luck!!

Won't turn over with kill switch on.

D'oh. See? I told you I'm stupid...

 

[ionbeam]

Some of the following has been checked but I'll include it anyway:

With the ignition key on - +12 volts on the Red/Black wires on the coils

Verify - the Orange and Gray wires directly from the ECU to coils (no connectors) are not broken

Verify - the plug caps are on and the plugs are good

If all this checks out then the Crankshaft Position Sensor and the timing wheel under the timing chain cover needs to be checked, the ECU uses this sensor to calculate spark timing. It isn't uncommon for wires to get pinched between the timing cover and the engine.

 

[user 89005]

First day here in Southern Germany that brought out the fair weather riders, probably safer to be working on the bike!

Yes, 12v at the primary coil side. No spark during the diagnostic function test.

If I understand Donal's idea correctly, by pulling the ECU wire from the coil I should get a spark during the diagnostic function check. If I do get a spark then the ECU is bad, because the ECU is not isolating the ground and thus preventing the spark?

Notes: I double checked that both wires from connector at the ECU to the coils have continuity.

All switches, sensors and connectors are good in the ignition system.

Issue is not a fast start nor are the cylinders flooded and I see no unrelated faults...except for the operator!

 

[audiowize]

Ouch, $900.Before I blow the dollars, is there another way to confirm an ECU failure?

I see plenty of used ECU's on eBay for $50-200. On the less expensive end of things, spending $75 for an ECU and swapping them out is still a better deal than paying for dealership service.

Having both coils fail at the same time is highly unlikely, and you've confirmed that both coils don't fire. You have also measured +12V available at the coils, so it's up to the ECU to sink current through the coils to provide your ignition.

As others have mentioned, crackshaft/camshaft position sensor problems will manifest as this exact issue. I can remember resurrecting a car that I mothballed some years ago, and it would turn over endlessly without firing until I looked at what was coming out of the crankshaft position sensor, which wasn't functioning properly. For whatever reason, the car's ECU couldn't throw a code for this, as it was patiently waiting for the sensor to report.

The one other thing you might want to measure is the DC resistance of the primary winding on each coil. They should be the same, and I would expect them to be somewhere between 2 and 5 Ohms. If you had a shorted coil primary, the dissipation through the current sinking transistor in the ECU would become insanely high. If Yamaha designed the ECU elegantly, they may have used a single die with two transistors as coil drivers, so a single shorted coil could overheat and pop the whole die, potentially damaging the ECU. While this all has the protection of a fuse, we don't call transistors "3 legged fuses" for nothing!

 

[Donal]

First day here in Southern Germany that brought out the fair weather riders, probably safer to be working on the bike!
Yes, 12v at the primary coil side. No spark during the diagnostic function test.

If I understand Donal's idea correctly, by pulling the ECU wire from the coil I should get a spark during the diagnostic function check. If I do get a spark then the ECU is bad, because the ECU is not isolating the ground and thus preventing the spark?

Notes: I double checked that both wires from connector at the ECU to the coils have continuity.

All switches, sensors and connectors are good in the ignition system.

Issue is not a fast start nor are the cylinders flooded and I see no unrelated faults...except for the operator!

Not really! My suggestion was to pull the wire from the ECU side of the coil then use another wire to 'flash' the coil (make and break the connection from the coil to ground). This will simply test the coil with the ECU out of the game.

If the coil is OK then we have to find out why the ECU is not doing it's job.....

As several others have already said it is unlikely that both inputs on the ECU would have failed simultaneously.

The most likely thing is something is telling the ECU not to operate the coils.

 

[Mihalis fjr]

Have you check the crankshaft sensor if it is ok?Black & Grey wires in its coupler.It should shows 420-569 Ω.

Also have you check with your multimeter if from the crankshaft sensor the wires from its coupler,to the ECU coupler is ok?Gray & Black/blue wires.

 

[RaYzerman19]

I'd also check the cylinder identification sensor (top right of valve cover, white connector is at right end of throttle bodies), and lean angle sensor (can't remember, does lean angle sensor prevent turning over the engine)