Fuel Injector sticking

[yamafitter]

I noticed the FJR was running rough and wouldn't idle properly ever since taking the bike out of storage. I put the bike away in mid October thinking I was going to get in a few more rides last season and with the extended winter, we just had time for a few short rides this season so far.

I pulled the air filter and the K&N was barely showing any dirt so I reinstalled the filter. The plugs were a little old so I installed new iridium plugs and borrowed RaYzerman's Carbtune to check TBS. The bike was still running rough and would miss from time to time.

I noticed on the Carbtune that it was always #3 cylinder dropping out.

Ray stopped in and I had his well tuned ear give a listen. It was either a fuel delivery or spark issue. Since the plugs were brand new and the way the bike would stumble on idle from time to time Ray & I both suspected a fuel issue.

I have a Power Commander USB III and we thought at first that the Power Commander may be reading the throttle position incorrectly so we did a reset and reprogrammed throttle position. That procedure had no effect on the rough idling. We then pulled the leads from the injectors one at a time. Each time removing the injector lead made the idle worse expect for #3 injector which had no effect on the idle. We found the problem.

Now for the solution. I went online to check parts availability and pricing. Online the parts are roughly $125 for injector, gasket & o-ring. My local dealer in Canada listed the injector for $195 and the injector is on back-order. My dealer then suggested that I take the injector over to a local diesel shop that has specialized equipment for testing and cleaning injectors. I gave the shop a call and for $25 they will run a diagnostic on the injector and run it through their injector cleaning jig a couple of times.

If this works out we're golden. I'll know if we have success tomorrow.

 

[okimic]

I'm very interested in hearing how you make out. I have a similar stumble I need to get to the bottom of.

Cheers!

Mike

 

[kaitsdad]

Let me know if you need an injector -

 

[RadioHowie]

I'm at a loss to figure out how a diesel injector shop can do anything with a gas injector...two VERY different types of animals...so I'm adding this LINK to a company that helped me out with plugged injectors.

 

[RaYzerman19]

The FSM is woefully inadequate when it comes to injectors. Two main issues it can be are mechanical (plugged/partially plugged) or electrical (inoperative, improper resistance). In the FSM page 8-55, you can actuate the injectors while in diagnostics mode. That will only tell you that electrically it is OK if it is clicking like a solenoid, then it is likely plugged.

The miss is at idle and improves once around 2000 rpm or higher.... I suspect partially plugged. The injector guy will probably know better, and I hope he can help you out by getting it cleaned so you don't have to spend the big bucks.

 

[yamafitter]

I'm at a loss to figure out how a diesel injector shop can do anything with a gas injector...two VERY different types of animals...so I'm adding this LINK to a company that helped me out with plugged injectors.

While what you say is true about there being a difference between gas and diesel injectors this particular shop is the only shop in the area that has the specialized equipment for working on both types of injectors and have the ability to clean a blocked gas injector. The other shops (marine, auto & motorcycle shops) farm all their injector work out to this shop.

The FSM is woefully inadequate when it comes to injectors. Two main issues it can be are mechanical (plugged/partially plugged) or electrical (inoperative, improper resistance). In the FSM page 8-55, you can actuate the injectors while in diagnostics mode. That will only tell you that electrically it is OK if it is clicking like a solenoid, then it is likely plugged.

The miss is at idle and improves once around 2000 rpm or higher.... I suspect partially plugged. The injector guy will probably know better, and I hope he can help you out by getting it cleaned so you don't have to spend the big bucks.

Unfortunately it does not seem to be a plugged injector. The shop ran the injector on their test rig and checked the spray pattern and could not find any faults. At their suggestion I switched #2 & #3 injectors to see if the fault would follow the injector but the problem still appears to be on #3 cylinder.

I checked spark on #3 and the spark appears good so it now seems to be a signal issue going to the injector. I am going to try the diagnostic mode test so I can check the signal going to the injector and then go from there.

 

[03HiYoSilver]

yamafitter,

Have you checked your spider connections?

I know when I cleaned the GenI Main Harness Connector, this fixed the same type of problems you are going through. On the GenII's it was most likely split up into the Spider Type connections.

When my #4 fouling situation was finally resolved, it was cured by replacing the Throttlebody Assy (which is a rare case).

Good Luck with your fix.

 

[joebiodiesel]

Don't forget to run a compression test. If you have a miss, and it's not spark, and isn't fuel (unless you have an injector control problem) then you defeintely need to check compresion on all the cylinders.

If you want to find out of it's an injector control problem, can you swap the #3 injector connector with the one next to it to see if the miss moves or not? The harness may not stretch that far...

Joe

 

[yamafitter]

yamafitter,

Have you checked your spider connections?

I know when I cleaned the GenI Main Harness Connector, this fixed the same type of problems you are going through. On the GenII's it was most likely split up into the Spider Type connections.

When my #4 fouling situation was finally resolved, it was cured by replacing the Throttlebody Assy (which is a rare case).

Good Luck with your fix.

As a precautionary measure I installed the Brodie Grounding Harness before my trip out to WCR on Vancouver Island last year. I also had some of the other spiders apart and used dielectric grease during reassembly. I'm going to look elsewhere first for a problem but I may end up coming back to this if other probable solutions don't work out.

Don't forget to run a compression test. If you have a miss, and it's not spark, and isn't fuel (unless you have an injector control problem) then you defeintely need to check compresion on all the cylinders.

If you want to find out of it's an injector control problem, can you swap the #3 injector connector with the one next to it to see if the miss moves or not? The harness may not stretch that far...

Joe

Excellent tip Joe. I plan on disconnecting all the injectors except for #3 and then using the diagnostic mode to fire the injector. It won't be a problem shifting the harness to use #2 injector lead to make sure it's the input to the injector or the injector itself.

I doubt this would work with the bike running though since the injector signal should be timed to the intake stroke of the cylinder. By moving the leads around the injector signal would now be mistimed I would think.

I have noticed one problem. When I measured the resistances of the injector coils I got readings of 11.7 - 11.8 ohms for injectors 1, 2 & 4. The reading for injector #3 was 13.0 ohms. According to the diesel mechanic that checked the injector that should not be a problem. Also when I reinstalled the injectors I am relatively confident that I switched injectors between #2 & #3. If the problem is the injector, the problem should now be with cylinder #2 but it's not.

 

[joebiodiesel]

I doubt this would work with the bike running though since the injector signal should be timed to the intake stroke of the cylinder. By moving the leads around the injector signal would now be mistimed I would think.

Not true on our bikes as the injectors are all fired at the same time. Even if the bike was sequentially fired, it would really make very little difference at idle if you swapped the injector connectors. They all fire on a closed intake valve anyway, so having a few more crankshaft degrees for the fuel to mix in the valve pocket doesn't hurt it.

I agree that 13 ohms on that injector is not enough to cause a miss on that cylinder. It looks like your next move is to buy/borrow a good compression gauge.

Joe

 

[Strayshot]

I know it may be reaching, but is it at all possible that the bypass screw on the #3 throttle body got set out of whack? Have you checked your TBS?

 

[Bungie]

3rd gear, empty road, pin it until you run out of road or your license.

Cdn tune up does wonders.

 

[03HiYoSilver]

Wonder if Yamaha Ring Free or SeaFoam treatment would help if you had some carbon on the Valve Face ... like DCarver had a few years back?

 

[frito1]

Not true on our bikes as the injectors are all fired at the same time.

No disrespect, but I got to ask the source of this information. The wiring diagram shows 4 leads of 4 different colored wires from the ecu to the injectors. Why bother making each lead unique if it doesn't matter which injector it's hooked to?

 

[RadioHowie]

Not true on our bikes as the injectors are all fired at the same time.

No disrespect, but I got to ask the source of this information. The wiring diagram shows 4 leads of 4 different colored wires from the ecu to the injectors. Why bother making each lead unique if it doesn't matter which injector it's hooked to?

Got me scratching my head, too. I can see wasting a spark on the exhaust stroke, which the FJR DOES do, but wasting a spritz of gas???

How do I turn that feature OFF and double my gas mileage??

 

[rushes]

3rd gear, empty road, pin it until you run out of road or your license.

Cdn tune up does wonders.

+1

An move south so yer poor bikes don't hav ta try an recover from a induced coma.....

 

[ionbeam]

My FSM specifically says "Normal synchronous injection" and goes on to supply a timing table that shows injector sequence determined by the Cylinder Identification Sensor and the Crank Position Sensor.

 

[RadioHowie]

In case some of ya didn't get that, what Ibeam just said was "the injectors don't squirt simultaneously."

 

[Constant Mesh]

Injection at engine startup is a special case where multiple injectors open simultaneously.

From the service manual:

"During starting the injectors of all the cylinders inject fuel only once immediately upon receiving the signals from the sensors during the cranking of the engine. This is called asynchronous injection.

After the asynchronous injection is completed, and until the ECU receives signals from the cylinder identification sensor, the injectors are actuated in pairs in sync with the signals from the crankshaft position sensor -- cylinders 1 & 4, cylinders 2 & 3."

The cylinder identification sensor is needed to identify cylinder 4. Once cylinder 4 is identified all cylinders are identified.