09 XTX running on two cylinders. NEED HELP PLEASE!

[603NytroXTX]

Okay so I've read as much as I can find on here and everywhere else that's relevant. Here's symptoms of sled.

Sled:
09 XTX: K&N intakes, Power Commander 5 running Ulmer map, Hindle full exhaust, installed Autotune but turned off, trail tank, other stuff listed in signature.

Symptoms:
Starts fine but runs rough. Definitely an issue with 1 cylinder and based on review of spark plugs both old and brand new set it's the middle cylinder with the issue. Had same exact issue last year but after about 15 miles of riding it backfired hard and then ran perfect for the rest of the year. At some point during the summer same issue happened again. Have done 150+ miles this year and it did not come back into it. When it first happened this year it started to pour white smoke when returning to idle after full throttle pulls on the stand in garage and would subsequently stall out. Also my O2 sensor would drop fo 9.99 when white smoke started. O2 readings before that were in normal range. White smoke has since disappeared entirely. It stalls when returning to idle about 50% of the time and seems to be when it comes down in RPM quickly. When it does stall it smells of gasoline very bad and very quickly. Give it 30 seconds or have to give it some throttle during cranking and it starts back up. Very weird thing is that during riding it will come into it semi consistently at 7500ish RPM and if I control the throttle I can keep it running good between 7500ish and 7800ish. Also very rarely it will come into it at full throttle above 9000 and hit rev limiter but as soon as I let off it goes back to two cylinders. It feels like a shot of nitrous or big turbo kicking in when it comes into it.

What I've done so far:
-Checked and changed plugs all three cylinders
-Check for spark on all three cylinders
-Changed out all three injectors
-Cleaned and greased all electrical connections during spark plug and injector change

What's next:
-Check intakes
-Check throttle bodies.
-Check ECU
-?

I do have my buddies 09 XTX to swap things in and out of to troubleshoot which will be helpful. Looking for any suggestions from you guys. I'm really hoping it's not something electrical because I hate that stuff.

Any help is greatly appreciated. I've talked to @Srxspec and @grizztracks back when I thought it might be a head gasket issue due to the smoke but things have evolved since riding 150 miles.

 

[grizztracks]

Try swapping out the ECU's to eliminate that as the problem.

 

[603NytroXTX]

@grizztracks I'm going to swap out the ECU tomorrow to rule that out. I ruled out throttle body(s) and intake(s) this afternoon. Found this post which matches my symptoms perfectly, has similar mods and the video clip he posted is identical to what mine sounds like https://ty4stroke.com/threads/nytro-hurrican-performance-kit-help.139279/page-2 which seems to point towards ECU issue as well. What are your thoughts on the stub shaft/reluctor ring from this thread? I don't know much about this stuff at all https://ty4stroke.com/threads/09-nytro-idle-help.156587/page-2 .

 

[grizztracks]

If it's not the ECU I'd continue by checking the reluctor ring and valve lash clearance. Both of these are simple checks that require no parts unless there's a problem.

 

[603NytroXTX]

Only thing that make me believe it's not mechanical is that I had same issue last year and then it came out for the whole winter until I put it away for the summer. I find it hard to believe reluctor ring or valve issue would revert itself until the sled was put away but I have limited knowledge on both of those.

 

[603NytroXTX]

@grizztracks Swapped ECU's today with no avail. Also checked primary and secondary resistance on all three coils and they are good. Going to head for crankshaft sensor and reluctor ring check next.

Something to note. Had air filter off today and could see inside throttle body when going WOT. First thing is I swear it looked like the middle injector was spraying more fuel than other two cylinders (all three new injectors) and after I turned the sled off and held throttle down I saw a few drips after some time from middle injector and no drips from either other side. Probably just a bias because I'm 99% sure it's an issue with middle cylinder based on spark plugs old and brand new but I swear there was a difference.

Where are all the grounds that you always go check @grizztracks ? Need to check grounds and probably do full sweep of harness. Did not find any rub through on the common spot by casting nub.

 

[grizztracks]

A bad injector is definitely a possibility.

The splice blocks look like a connector that's not being used. You can always distinguish a splice by the wire color code. If all the wires going into the block are the same code then it's a splice.

 

[603NytroXTX]

@grizztracks Thanks for the pic and explanation. Will run those down tomorrow and make sure they all look uniform.

Could be injector wiring but I've ruled out injectors as I put a brand new set in with no change in behavior.

I had an idea today that I'll probably try if I can't narrow this down soon. Let me know what you think but I'm going to completely swap the entire front clip with subframe and wiring from his sled to mine. Will take some time but I haven't even been able to narrow it down to fuel, spark, or mechanical at this point and I'm not just gonna keep throwing new parts at it. This should allow me to narrow it down drastically by putting a whole new front end on it.

 

[olypopper]

Compression and leakdown should be performed BEFORE you throw any more parts at it. If those are good, I'd lean heavily towards a wiring problem like a broken or chafed wire. If the wiring harness tests ok, swap another ecu in and see if you have a bad injector driver. I've seen lots of Yamahas over the years making white smoke/flooding a cylinder to find a bad ecu injector driver (stuck on spraying fuel)

 

[603NytroXTX]

@olypopper Thanks for the input! I've tried swapping the ECU and no change. I need to try and find the specs to test wiring harness at this point I guess. Will get to a compression and leakdown test when I get the tools for that.

 

[603NytroXTX]

Update @grizztracks @Srxspec

I have narrowed it down to the wiring for injector #2. I used the diagnostic mode and found that I didn't get any response/clicks/noise on Diagnostic code #37 which is injector #2. I tested code 36 and 38 and could easily hear the 5 clicks for injector #1 and #3 but absolutely nothing for #2. (As stated before I replaced injectors early in the troubleshooting) Please correct me if I'm wrong but based on the stalling out, smelling of fuel, black spark plugs, and backfiring I believe it to be a ground issue that's causing the injector to be stuck open. Not sure how this theory jives with it "coming into it" around the 7500k RPM mark but at least I've got something to continue to chase. Not too happy to be chasing a wiring issue so any hints or tips of where to start would be incredible. Thanks guys!

 

[olypopper]

Start simple, test for power at the injector clip AND ground when it's commanded by the ECU. I like to use a noid light if you can find one. You can also use a test light during the injector test.

 

[603NytroXTX]

Start simple, test for power at the injector clip AND ground when it's commanded by the ECU. I like to use a noid light if you can find one. You can also use a test light during the injector test.

Thanks Olypopper! I've actually got some noid lights in my Amazon cart but held off because I want sure what size would work and didn't want to get a kit that didn't have the core size. Do you know which size noid light works in this application?

Thanks!

 

[olypopper]

Sorry man, I don't know. I've got a Blue Point kit that I use and just grab whatever works.

 

[603NytroXTX]

Sorry man, I don't know. I've got a Blue Point kit that I use and just grab whatever works.

No worries man! Much appreciate the help. I'm gonna run out soon to grab a kit and pray it fits.