What N' The Hell...........

Hello all. I got a good one here. I just picked up a 08 WRR that had starting issues. Good price $1500. Real clean, well maintained. So here's the problem. It is overly rich when it is cold. Real strong fuel smell and no start. I have checked all the codes and run the diagnostic checks through the dash. All sensors read correctly and there are no codes. I have taken off the throttle body to check it out. Charged the batt. and tried using jumpers from a good car batt. I can unhook the coolant temp sender and hold the throttle wide open while cranking for about 30-40 seconds or maybe a little longer and I can get it to start. If I hold the throttle open for a bit, it will clear out and start to run. I can then hook back in the coolant sensor and the bike will continue to run. It seems to run a bit rich untill it is fully warmed up. I tried adjusting the CO levels with no luck. I also unhooked the FMF proggramer with no luck. The bike has a 2 Brothers pipe, flapper mod, AIS removed, EXUP removed. I have checked all the connectors and checked resistance values of the sensors at the ECU and the sensor itself. If you have any ideas please let me know. I really would like to get this thing running right. I've been wanting one since they came out and would really like to get to enjoy it. Thanks for your time and help!

Check the Air Temperature sensor. Two reported problems with it in that 'other' forum (adventure).

Thanks for the reply, I checked the sensor, (Ohms) and the digital display reads the exact same as my infared temp gun. I'll go ahead and check it again. Thanks!

Just checked the resistance on the air sensor, reads correct according to the service manual.

Here is a random thought. Is it possible that one of the injectors is sticking open. I am not a FI genius and not 100% how they work. But, if they open different at start up when cold compared to when the bike is running could cause a problem. Flooding the engine at startup. ???

Good idea, that's what I though also. I was thinking maybe a leaking or stuck open injector causing the engine to flood out when cold. It checks out OK. I was wondering if there is anyway the injector could have high or low resistance causing it to add too much fuel? There is a FID actuator on the right side of the throttle body that adds air when the bike is cold. I believe that the bike should have a higher idle speed when cold. The FID adds more air and then slowly closes the air bypass when the coolant heats it up. I'm debating replacing the whole throttle body. I don't want to throw a $400 part at it if I'm not sure though.

If you think it might be the injector, send it to witchhunter performance and have them test, clean, rebuild, and test it again. It's good peace of mind and cost about $25/injector last time I had it done. They'll be able to test flow pattern as well as volume and be sure it's where it should be. I did this for my turbo car to make sure I had a good pattern and flow match between cylinders. Sent them 8 and picked the closest 4 to use.

Best option is the air bypass you were referring to. From my personal experience with other vehicles, this is much more likely than a fuel injector issue (I've had 4 idle air control/fiddle/air bypass valve failures on 3 cars in 10 years). Modern fuel injectors are just about the most reliable component of an automobile (I've had zero fuel injector failures on 8 cars in 15 years). If the previous owner used a coolant that isn't aluminum friendly there could be corrosion in there jamming it up. You may be able to pull it apart and rebuild that component to "fix the glitch".

Thanks for the info on the injector! I did pull apart the air bypass gizmo and clean it out (looked clean anyway). I also tried maually moving the air bypass plunger to allow more air in during starting. When I get it running, it does change the idle speed. There is a small nut on the bottom of the valve that adjust spring pressure on the thing. Kinda don't want to mess with that because no matter what it still is hella rich cold starting. Anyone think it might be tight valves? It has 5600 miles on it and runs once I get it started. Also appears to be well maintained.

Does anyone know what the injector resistance should be? I have 11.8 Ohms. Not sure if thats right? I can't seem to find any info on resistance checking in the service manual.

Grsmnky78 wrote:

Does anyone know what the injector resistance should be? I have 11.8 Ohms. Not sure if thats right? I can't seem to find any info on resistance checking in the service manual.

Should be fine. Most are between 11.5 and 14 ohm unless they are low impedience injectors.

Typically a failed injector will show an open circuit (if it's stuck closed). If it functions at all, the coil is fine.

It could be leaking if someone ran fuel with too much ethanol and dissolved fuel line or filter is jammed up in the seat. Witch Hunter can answer that.

Thanks for the info Arkmage. I did pull the injector and it sprays nice while cranking the engine over. It did not appear to leak at all when I primed the pump.

Think I got it tracked down. It only has 100 psi of compression when hot. Did a leak down test and it had 70% at TDC leaking out the intake valves. Guess I'll have to adjust them or take it to the Yamaha shop & have them do it. $175 quote. Anyone else have valve issues at 5600 miles? Seems kinda weird? I'll update on what happens after the adjustment. Thanks again for the help!

Ouch... I hope they just need adjusting but it is awful shocking that they are leaking at such low mileage.

Possible your cam chain tensioner failed and the intake cam skipped a tooth? May be worth pulling the valve cover and checking the mechanical timing before you start shopping for shims.

Good Idea, I'll do that. I'll definately check the valve clearance before I go any further. It does'nt appear to have any cam chain related rattle in it?

Bummer i didnt read this sooner, had exactly the same symptoms with an fzr 1000, valves were held open.
It's not a massive job to do yourself, setting the cam chain tensioner is the hardest part from what i hear.
Could have just been ridden real hard for those miles & slightly soft valves...
easily fixed anyway.

Thanks for the info xy500! I hope thats it. I'm gonna borrow a friends fuel pressure tester first. He seems to think it might have low fuel pressure. I have heard that low pressure will make the injector spray weird and cause flooding while trying to start. Either way I'll check both and let ya know what happens.

Grsmnky78 wrote:

I have heard that low pressure will make the injector spray weird and cause flooding while trying to start.

Correct. The lower pressure results in poor fuel atomization. It's particularly an issue at low engine rpm (low air velocity through the intake) and cold temperatures (less heat to help evaporate the fuel in the intake).

Basically, the fuel comes out in too big of droplets for the low velocity and cool air to properly mix it into the air. As a result it collects on the intake runner and actually drips into the cylinder as a liquid instead of being carried in as a vapor.

It's certainly worth checking.

Grsmnky78 wrote:

Did a leak down test and it had 70% at TDC leaking out the intake valves. Guess I'll have to adjust them

No matter what, you're going to have to sort that out, low fuel pressure or not.

OK, checked fuel pressure, spot on 36 PSI. Finally got the valve cover off and found that the right intake valve has no clearance. Not sure what N' the hell could cause that? All the other valves are in perfect spec. The lifter bucket had some weird wear on it kinda like the hard facing is coming off. I switched shims and buckets from left to right and the clearance is still tight. With the cams out I have only 2-3 percent leakdown (nice!). I'm gonna buy some shims and a new lifter bucket and put it back together. Not sure if the valve will last, but only time will tell...... Stay tuned I'll let ya know what happens. Might be about a week till I get the parts and time to finish it up. Feel free to let me know what ya think. Thanks.

Grsmnky78 wrote:

OK, checked fuel pressure, spot on 36 PSI. Finally got the valve cover off and found that the right intake valve has no clearance. Not sure what N' the hell could cause that? All the other valves are in perfect spec. The lifter bucket had some weird wear on it kinda like the hard facing is coming off. I switched shims and buckets from left to right and the clearance is still tight. With the cams out I have only 2-3 percent leakdown (nice!). I'm gonna buy some shims and a new lifter bucket and put it back together. Not sure if the valve will last, but only time will tell...... Stay tuned I'll let ya know what happens. Might be about a week till I get the parts and time to finish it up. Feel free to let me know what ya think. Thanks.

With that low of miles that's pretty strange. I wonder if that valve happens to be defective material and is already stretching?

If it was caused by an over-rev I'd expect both intake valves to be stretched a similar amount. Can you post a picture of the wear you are talking about? It's possible of that particular cam lobe is at the end of the line for oil it may have gotten starved. That would cause the one valve to overheat and stretch faster.

Yeah, it's kinda weird. I'll try to get a couple pics of the wear. It's not real bad and it's a small part so I'll do my best. Also I can't seem to upload pics to here wortha damn, but I'll try.

thats a bummer man, hopefully it's just the bucket and not the valve. Good luck.

Grsmnky78 wrote:

Also I can't seem to upload pics to here wortha damn, but I'll try.

click me for help <---

Thanks Motokid! Think I figured it out. Figured I'd share a pic of my old 600 just to make sure I got it.https://servimg.com/view/17849667/11][/url]

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