[NoLegs]

This will be wordy as I am trying to establish a point through several recent circumstances that got me to tonight. Bare with me...

Of course, there is a disclaimer: I'm only sharing my experience with everyone and it's up to each of you to decide to do this as I am not responsible for what modifications you do to your bike.

I don't frequent the forum very often, but I did come here a few months ago to get the skinny on this Lean condition this bike seems to run in. I of course, came across the "O2 Mod" where you run a resistor in series with the "white wire". I did the mod and nothing, absolutely zero change in the way the bike ran, so I removed the resistor and went back to being annoyed with the chugging (most notably in 2nd gear @ ~27 mph). I figured one day I'd get a tuner of some sort and be done with it, but it still hasn't happened yet and tonight, I think I made some headway!

My discovery stems from working on a 1996 Z71 throwing a catalytic converter code (on GM it's code P0420) due to the upstream and downstream O2 sensors having nearly identical readings (the downstream O2 sensor should read "more lean" than the upstream). Come to find out, the cat is gutted because the truck has 230K miles and the converter has simply melted away... Anyways, this annoyance sent me to several forums (mostly performance related) talking about how to ditch the cats and not flag a code. I concluded that the 3 main remedies for this was:

1) Reprogram the ECU to ignore the sensors ($$$$$)
2) Buy O2 Sensor simulators ($$$)
3) Mod the (working) O2 sensor to send back a "leaner" signal ($) <---cheap and easy!

I've found that people where accomplishing #3 two different ways:

1) Modifying spark plug "non-foulers" to distance the sensor from the exhaust system. One of many threads with pictures
2) Modifying the wiring to decrease the signal back to the ECU saying that it is leaner than it is actually reading. DING DING DING

AND THIS FOLKS IS WHERE I'VE REACHED THE POINT.

I found several threads on modifying the wiring but none had a good explanation on what was actually going on and why it worked until I found this page explaining in great detail why it works.

By running a 1M ohm resistor in series with the O2 Signal wire and running a 1uf capacitor parallel to the O2 - wire, it decreases the signal from the downstream O2 sensor back to the ECU, reporting a leaner condition. This SOLVED my P0420 code and then I got to thinking....maybe I could apply this fix to my bike, so I pulled the harness back out (I'm referring to the extender that came with my full Cobra Swept exhaust) for modification.

SOOOO, using the information from the "$6 DIY O2 Sensor Simulator Link" and the wiring diagram for our bikes (service manual) AND looking at generic photos of O2 sensors on the web (google images) I determined that the resistor needs to go in series with the BLUE WIRE and the capacitor needs to be in parallel (harness side not sensor side) with the BLUE WIRE AND WHITE WIRE.

I then took the bike for a ride (~5 miles) and YES, there is DEFINITELY a difference. No more chugging in 1st at 10mph (and I was idling, like through a parking lot - something I couldn't do before without riding the clutch). No more "hesitating" in 2nd at 25mph or 3rd at ~35-40mph. My bike is running like I think it should!

Anyway, I thought I'd share this information with all of you to hopefully collect more data and see if it helps anyone else, because the other O2 mod where you just put a resistor on the ground wire seems to be hit and miss at best between everyone. ALSO, I hope I'm not premature in releasing my findings, but I was just so excited that I felt a REAL change in how the bike is running that I wanted to let everyone know we might have an actual working fix to the chugging.

I'm also real big on pulling plugs to check for changes, so I'm gonna put some miles on the bike this way and see if it is indeed running more rich. Will report back when I'm able to ride (been raining here).

 

[11Stryker]

Great Write-up NoLegs! Sounds like you know your ship and have researched this well! I look forward to hearing your results also after getting 100 miles or so on this set-up. Please keep us posted. And we will need a wiring diagram and pics of this how to! Take care!

 

[1304cc]

Good stuff! And yes, a how-to please.

 

[NoLegs]

Image uploaded...

 

[NoLegs]

Only rode about 20 miles earlier today and just pulled the plugs and there are definite signs of the cylinders getting more fuel. There is very light tanning on the ceramic where before they were pretty white all the way around. Hopefully I'll get more miles on it this week to check again.

Also, during my abrupt ride today, I was purposely trying to ride in the known power zone where (before) I got the most hesitation and today I got nothing. I was also able to idle through a parking lot without riding the clutch.

Things are really looking positive so far on this particular mod. My goal is to be able to change the airbox without buying a tuner, but I won't take that leap until I know for sure I'm getting enough fuel.

More to come...

 

[11Stryker]

Job well done NoLegs!

 

[jmayhew72]

Bumping an old thread here but I'm wondering how this mod has been working for you since you posted this. I have the cobra swept pipes, air intake and fuel controller on my stryker and I have the same chugging issues but at slightly different speeds. I gut an update to the controller from Cobra but it didn't really help much. I'm considering trying this mod and thought I'd see if you had any update.

 

[EagleEye45]

I would Still look to Ivan's ECU Flash, This is Truly the best Bang for your Buck IMO. If you are interested, just give him your current set-up of the Modification you currently have and he will set the parameters for a basically Plug and Play set-up. This is a real occurring problem with the California bought bikes and the Smog setting they come form the factory with.

 

[jmayhew72]

Thanks, that looks great. I'll contact him when he is open again at the end of this month.

 

[muskie]

Thanks, that looks great. I'll contact him when he is open again at the end of this month.

Seriously, best bang for your buck. You will not be disappointed.

 

[27193]

Bumping an old thread here but I'm wondering how this mod has been working for you since you posted this. I have the cobra swept pipes, air intake and fuel controller on my stryker and I have the same chugging issues but at slightly different speeds. I gut an update to the controller from Cobra but it didn't really help much. I'm considering trying this mod and thought I'd see if you had any update.

With close to two years and no update, not very optimistic. Even though you are still running on the modified O2 circut, there are alot of other little fixes that a reprogram does and can be modified to fit any application.

Here is some food for thought read this thread post #68 http://www.yamahastarstryker.com/21...tory-ecu-change-air-fuel-ratio-co-mode-7.html From someone who knows about how our ECU works on this bike! This has convinced me to not hack any wires or mess with any settings.

So while this may work when just putting around( which may be enough for some) upon decel the injectors shut off. Also if the O2 works up to 40% throttle then you would be adding fuel to that range as well weather it needs it or not (a dyno run or A/F setup would be only real way to physically see IMO).

Here is a quick summary from that post:

When the ECU turns off the injectors on decel, there is no outside adjustment that can make them turn back on... This CO adjustment has no effect whatsoever on this.

Also, when the O2 is doing it's work (up to 40% throttle on this model) it will override any setting that is adding fuel.... if you disconnect the O2, then the CO setting/adjustment will have more effect at the tiny throttle openings (closed throttle basically).

However, as long as the ECU is looking for the O2, the mixture will make very wide swings from rich to lean and will be unstable at the same throttle position. This is why Dynojet supplies O2 controllers with their power commanders on the newer bikes. (these don't really work very well, but much better than nothing)

The best way to get a tunable and stable mixture, is to turn off the O2's function inside the ECU and then the bike has a stable and easily adjusted mixture.

Also, with ECU flash done properly, getting both cylinders running the same mixture and getting both injectors calibrated the same, disabling fuel-cut, getting the ignition timing issues adjusted properly for both cylinders really makes a nice difference to how the bike runs.

I am hoping to get up to Ivan's shop soon as I am all stock, and want this done before winter.

 

[jmayhew72]

Just curious what happens with my existing Cobra FI2000R PowerPro Fuel Tuner. Does it still stay connected or does it need to be removed once this procedure is done?

 

[27193]

Just curious what happens with my existing Cobra FI2000R PowerPro Fuel Tuner. Does it still stay connected or does it need to be removed once this procedure is done?

Keep the tuner don't do the mod.

 

[11Stryker]

Keep the tuner don't do the mod.

YEp YEp

 

[gerdawg]

With close to two years and no update, not very optimistic. Even though you are still running on the modified O2 circut, there are alot of other little fixes that a reprogram does and can be modified to fit any application.

Here is some food for thought read this thread post #68 http://www.yamahastarstryker.com/21...tory-ecu-change-air-fuel-ratio-co-mode-7.html From someone who knows about how our ECU works on this bike! This has convinced me to not hack any wires or mess with any settings.

So while this may work when just putting around( which may be enough for some) upon decel the injectors shut off. Also if the O2 works up to 40% throttle then you would be adding fuel to that range as well weather it needs it or not (a dyno run or A/F setup would be only real way to physically see IMO).

Here is a quick summary from that post:

I am hoping to get up to Ivan's shop soon as I am all stock, and want this done before winter.

With love, the Co mod's been working just fine for me. I've even had comments from folks that rode my bike before and after the mod and they've all commented that it rides much smoother with less jumpyness. I just gave up posting about it when folks started acting like I and the others who have tried it, were making things up or not getting the results that we claimed we were getting.

So for the record, I've had no problems with the modification so far, regardless of what Ivan said it would/could/won't do in his post. It's most certainly enriching the fuel and making the bike run better and I've also had that feedback from 3-4 other people on this forum that have quietly tried it they just didn't post their results after the thread that was started was derailed because it wasn't worth the hassle getting into it again.

It might not be a modification for everyone, based on what mods they have, but it certainly works for the folks that have tried it with just a slip-on. To each their own and I'm sure different mods will easily overcome the benefits of changing the Co.

For the record, I have over 3K miles on my bike after this modification and am not fouling plugs or having any indications that this is causing any problems with my bike and again as I stated before, unprompted, I've had guys that rode my bike before the modification commenting that it runs much smoother and wondering what I've done to correct the lag and jumpiness. The Co mod was the only thing that was changed.

 

[gerdawg]

BTW - I wouldn't do the O2 mod if it were me (since this is the thread we are on) as that would likely richen the circuit at all area's of throttle and lead to fouling of the plugs over time. (Which I believe others are experiencing.)

 

[27193]

With love, the Co mod's been working just fine for me. I've even had comments from folks that rode my bike before and after the mod and they've all commented that it rides much smoother with less jumpyness. I just gave up posting about it when folks started acting like I and the others who have tried it, were making things up or not getting the results that we claimed we were getting.

So for the record, I've had no problems with the modification so far, regardless of what Ivan said it would/could/won't do in his post. It's most certainly enriching the fuel and making the bike run better and I've also had that feedback from 3-4 other people on this forum that have quietly tried it they just didn't post their results after the thread that was started was derailed because it wasn't worth the hassle getting into it again.

It might not be a modification for everyone, based on what mods they have, but it certainly works for the folks that have tried it with just a slip-on. To each their own and I'm sure different mods will easily overcome the benefits of changing the Co.

For the record, I have over 3K miles on my bike after this modification and am not fouling plugs or having any indications that this is causing any problems with my bike and again as I stated before, unprompted, I've had guys that rode my bike before the modification commenting that it runs much smoother and wondering what I've done to correct the lag and jumpiness. The Co mod was the only thing that was changed.

BTW - I wouldn't do the O2 mod if it were me (since this is the thread we are on) as that would likely richen the circuit at all area's of throttle and lead to fouling of the plugs over time. (Which I believe others are experiencing.)

Getting info from you guys who are the guinea pigs for the CO changes is what others need. Post them up! Update that thread. Maybe there is more to it than what is understood.:noidea: I just used that thread as there is some good info from both sides I believe! The one thing that I'm trying to understand is if these adjustments help in some way with the decel fuel cutoff, that's a huge thing that I hate about the stock ECU program.

But modifying the O2 is NOT the correct way IMO from what I have read and understand about. And how sporatic it has worked for others.

I really want the lag and chugging to stop also, but I also want the other benefits of the flash, also getting way better gas mileage is a bonus! While $350 seems steep for most of us (including me) we will spend at least that on an exhaust so that is how I have justified it!

 

[gerdawg]

The one thing that I'm trying to understand is if these adjustments help in some way with the decel fuel cutoff, that's a huge thing that I hate about the stock ECU program.

I doesn't help with the fuel cut off at all. The cut off "is what it is" unless you remove it from the ECU as Ivan stated. However with that said, the amount of popping on decel IS certainly reduced (not eliminated) with the Co modification.

Fuel cut decel happens only above a certain RPM range and when the range falls below that value the popping decreases due to the additional fuel supplied at low throttle. It's not nearly as good as Ivan's mod, where he disables the cut off completely at any RPM range value. From my experience the popping is still much better than what it was stock, prior to Co values being modified. I'm sure Ivan's mod would be a much better solution if you're looking to completely get rid of the popping.

 

[mazilla]

I was running the CO mod up until a couple of days ago when I installed the EJK. I still had popping on hard decel, with the EJK I've had two pops since I installed it vs dozens on any given ride. I also have a 30 tooth pulley so it's difficult for me to narrow down exactly what the CO mode was doing since I failed to run a test ride without the CO adjustment to compare before the EJK. I didn't have any additional problems with the CO mod, it didn't hurt anything that I could tell but seemed to slightly improve the popping before. The EJK and 30 tooth($210 combined) is great, problems solved IMO...I wont be fiddling with the air/fuel any more I don't think so I can officially check that area off the to-do list.

 

[pajuggalo]

Nolegs I'm confused is this a take off on jacks O2 mod, because I thought it was the white wire that got the resistor, thanks