Hey guys, Those that have the "hesitation/flat spot" issues with their 6th gen. VFR's should go to http://www.bikersoracle.com/vfr/forum/ as it appears that Honda UK has found the problem with, as the Brits refer to it "fueling issues"
I won't go into it in length here, but basically it has to do with the O2 sensors being plugged in/wired backwards.
The thread is getting pretty long now but the "solution" from Honda UK is noted on page 8 of the thread under Jason Creasey's name....starts with "I've just spoken to Dave Hancock....."
Looks as if the whole problem has occured due to misconnections on the assembly line.
Of course, this happens just after I go with a PCIII and a custom map rolleyes.gif
This will come as very good news for a lot of Vtec owners. Personally, I'm guessing that I must be one of the lucky ones who hasn't had this problem However, I will be checking my own sensors out just to make sure.
Maybe someone could say where this sensor is pls. On left or right side, my crappy manual pics ain't so good. Do you have to take the fairing off to see this? I think mine runs fine but still want to check this out. Thanks, Hank
left side lower. the connectors are just forward of the water pump, the o2 sensors you can see under the bike. to actually get to them , i was able to just remove all the lower faring fasteners except the upper ones and removed the front clips of the left fairing to center fairing juncture, and pryed it open when i installed my o2 eliminators
vfr03silver, Jan 20 2005, 07:49 PMMaybe someone could say where this sensor is pls. On left or right side, my crappy manual pics ain't so good. Do you have to take the fairing off to see this? I think mine runs fine but still want to check this out. Thanks, Hank
I hate to break this to you but you will have to pay 04asphalt (Mr Frugal) royalties for the use of one of his avitars. I'm sure he will only charge about $1.00 a day. tongue.gif (insert Mr Frugal is a cheap bastage emitcon here)
vfr03silver, Jan 20 2005, 08:28 PMWait Wait, this is a new site now and I got it first! He'll have to pay me tongue.gif Thnx for the info much smile.gif
STOP THIEF! This isn't a new site, it's just new software. Mr Frugal will track you down next time you are in Michigan....you see he is too cheap to come to Florida to kill you, you will have to go to him. (insert shaking head emitcon here)
Hurricane249 Posted Today, 01:04 PM STOP THIEF! This isn't a new site, it's just new software. Mr Frugal will track you down next time you are in Michigan....you see he is too cheap to come to Florida to kill you, you will have to go to him. (insert shaking head emitcon here)
Ok hope no one has this one smile.gif but if they do I have a bunch of my own now... see I figured if I ripped off Mr Frugals I'd start to feel guilty. And even though I know he can't catch me, cuz the silvers are obviously faster then the blacks, I figured I might start to feel guilty every time I spent money for some strange reason!!! laugh.gif
Das Bone, Jan 20 2005, 06:50 PMHey guys, Those that have the "hesitation/flat spot" issues with their 6th gen. VFR's should go to http://www.bikersoracle.com/vfr/forum/ as it appears that Honda UK has found the problem with, as the Brits refer to it "fueling issues"
I won't go into it in length here, but basically it has to do with the O2 sensors being plugged in/wired backwards.
The thread is getting pretty long now but the "solution" from Honda UK is noted on page 8 of the thread under Jason Creasey's name....starts with "I've just spoken to Dave Hancock....." Looks as if the whole problem has occured due to misconnections on the assembly line.
Of course, this happens just after I go with a PCIII and a custom map rolleyes.gif
Allright, allright children knock it off! Stop fighting or I'll make you go to your rooms! mad.gif
Now, first off, let me admit that I didn't read all those cross threads over there at the UK site. That said, I must have missed something. If I read that correctly, the answer to my VTEC woes is to switch wiring to my connectors? Doesn't my O2 eliminators negate that? They aren't connected to anything and therefore don't know if they are front or rear. Am I supposed to trace the wires up to the top of the loom and switch them there? I am confused. I get this way lately with my medication. Please someone else do this first and post pics (lots of 'em) so us third graders can do it too. Thanks.
redsars, Jan 21 2005, 06:46 AMIs this for real, or an early April 1st joke ?
Hmmm I think it's real. Seems very plausible anyway. I haven't had a chance to check mine yet, but I'll be surprised if they aren't as should be. Would certainly indicate validity because I don't experience and flat spots. pretty kewl info hope it's right.
Allright, I just finished reading all eleven pages of the thread. All you need to do is click here. It explains what Honda UK explains to be our problem with the VTEC.
To summarize the O2 sensor with the black socket should be plugged into the top exhaust port and the white should be plugged into the bottom port. The picture below explains top and bottom and also shows what should be considered the wrong way of wiring. As the sensors themselves are the same, all that is needed to correct the situation is reverse the wiring so that the black sensor wiring from the loom connects to the top sensor and the white wiring from the loom should connect to the bottom. Is that understandable?
What remains is if this is the case, why does my and so many others fitted with PCIII and O2 eliminators still exhibit the problem? Oh well.
This situation is unfolding just within the last two days. I suggest we keep checking back to see if there are any changes on the UK site.
toneout, Jan 21 2005, 08:55 AMAllright, I just finished reading all eleven pages of the thread. All you need to do is click here. It explains what Honda UK explains to be our problem with the VTEC.
To summarize the O2 sensor with the black socket should be plugged into the top exhaust port and the white should be plugged into the bottom port. The picture below explains top and bottom and also shows what should be considered the wrong way of wiring. As the sensors themselves are the same, all that is needed to correct the situation is reverse the wiring so that the black sensor wiring from the loom connects to the top sensor and the white wiring from the loom should connect to the bottom. Is that understandable?
What remains is if this is the case, why does my and so many others fitted with PCIII and O2 eliminators still exhibit the problem? Oh well.
This situation is unfolding just within the last two days. I suggest we keep checking back to see if there are any changes on the UK site.
Thanks for the pic! that helps alot. I remember when I read the article something about syncing the starter valve too, but don't know enough about it to have any idea if it would have an effect. So in the picture it's the opposite of what it should be? sorry I just want to be sure smile.gif I may not touch mine even if it is wrong, cuz the bike seems fine, I'll wait to see what Honda says I guess. Thnx again!
The pic shows the wiring in the wrong place. The O2 sensor with the black lead should be on top and the white should be on bottom. DO NOT REMOVE THE O2 SENSORS. Just swap the wiring from the loom to the sensor if necessary. As the thread explains, this is not applicable to all bikes. Only some are affected. If your bike runs fine, don't fix it.
What remains is if this is the case, why does my and so many others fitted with PCIII and O2 eliminators still exhibit the problem? Oh well.
Wil, I read the first part of the whole thread a couple of days ago, and the reasoning of why just the 02 elims(PCIII too?) were seeming to cure the problem for many people, most of the time but still had intermittent occurrences of flat spots/hesitation was that two of the four cylinders were set to run leaner than the other two due to heat issues......so apparently the reason that it matters that the 02 sensors are plugged in to the correct connectors in the wiring loom going to the ECU is that the monitoring and therefor adjustments that the ECU makes are different dependent on which cylinders it is attempting to make corrections for.
Sorry as this is probably a poor description of the reason.....but that was my general take on it.
So, with the 02elims, they apparently just give a constant(static) signal to the ECU, but in some conditions(heat,humidity,ambient whatever) Since the ECU is not getting the the complete info that it should have gotten with the 02 sensors hooked up properly , it tries to make changes based on the 02 elim info that it's getting which sometimes will still cause the glitches.
I'm obviously not a tech-head, so You guys might really want to go check out the whole thread form the beginning to get the "real" story.
04asphalt, Jan 21 2005, 06:21 AM tongue.gif laugh.gif laugh.gif laugh.gif
He's BACK!! He's been lurking around unnoticed to see what you guys really think about him! You guys should be ashamed you probably hurt his feelings or something!
Getting back on track, It seems to me that Honda is compensating for a fuel delivery problem between the front two cylinders and the rear two. Or they are running the bike so lean that they really should have input on all 4 cylinders to allow the computer (ECU) to compensate fuel delivery at any moment to the engine.
On a curent model car they are using a O2 sensor in front of and behind the catilytic converter. To check unburned gases comeing out of the cat also. They don't check groups of cylinders or all cylinders.
I think on the motorcycle the airfuel ratio probly changes from cylinder to cylinder so much due to the intact tract that they will need to go to 4 O2 sensor.
Or they are running the bike so lean that they really should have input on all 4 cylinders to allow the computer (ECU) to compensate fuel delivery at any moment to the engine.
Vince, that's my take from what I've read....two cylinders are set to run leaner than the other two for heat/cooling issues.
Getting back on track, It seems to me that Honda is compensating for a fuel delivery problem between the front two cylinders and the rear two.
snip
The sensors are not set up for the two front cylinders and rear two. The sensors monitor the diagonally opposite cylinders and not the front/rear banks.
Jim, Jan 21 2005, 09:20 AMThe sensors are not set up for the two front cylinders and rear two. The sensors monitor the diagonally opposite cylinders and not the front/rear banks.
If that is the case they are running the sensors on a crank angle based fuel delivery or air delivery deficiancy. With lean mixtures everything has got to be just right to get the most usable performance without glitches. With ours being a V4 design engine the firing impulses due to crank angle may just need another fine tuning sensor such as the O2 sensors based on each crank pin throw or angle rather than a crank angle sensor only. But I would think that would be due to an ineficant air box design and related to how much air gets to each cylinder therefore the air fuel mixture sensors in the exhaust. Maybe a better presurizied air box would help you 6th Gen types.
Just did a cursory check on mine too and the white is on top/black on botom,i.e. backwards for what UK Honda is saying they should be.
As I mentioned, I've had a PCIII and map made so I'm going to have to decide whether to remove the PC and go back to stock with the correct hook up of the 02 sensors.
For those of us that have the flat spot/hesitation issues, I would definately check your 02 sensor arrangement and if it's backwards, switch the connections and see if you notice a difference. You need not even remove the whole fairing....just remove some of the fairing screws and you will be able to pull the fairing out enough at the bottom to check and then switch the connections if necessary.
I just went back on the UK board and they're letting MCN and RIDE magazine know about this and it sounds as if there are things happening at Honda in terms of rectifying this situation.
Just had another thought: If any of you that have had NO problems at all would do a quick check on the 02 conections to see if theirs are correctly installed....might be interesting???
So, if I plug the black male sensor into the white female sensor and the opposite for the other then that should solve the problem? Or, do I have to undo the looms and switch them? Thanks.
As mentioned above, mine were reversed (Black, bottom -- White, top). I switched the cables and did a brief test ride. I'm reluctant to jump to any conclusions but I was unable to detect any 5K surging. I want to ride it that way for a week or so just to be sure.
quicknick, Jan 21 2005, 02:03 PMSo, if I plug the black male sensor into the white female sensor and the opposite for the other then that should solve the problem? Or, do I have to undo the looms and switch them? Thanks.
Just switch at the connector. No need to trace them up the loom.
toneout, Jan 21 2005, 07:27 PMJust switch at the connector. No need to trace them up the loom.
Yup, what he said.
Any of you guys that have "perfect" running VTECs have time to check your 02 sensor connections yet? You don't even need to remove the fairing....just remove the bottom screws a nd a couple of the upper one's so that you can just pull the fairing out at the bottom to look up in there......same technique for doing an oil change without removing the entire fairing.
Would be very interesting to see how one that's never had any "fueling issues" as the Brits say is wired up.
P.S. Everyone that has had the problems, found that the 02 sensors were plugged in backwards, and switched the connections, please keep posting to let everyone know how your bike is running.
Das Bone, Jan 22 2005, 11:20 AMYup, what he said. Any of you guys that have "perfect" running VTECs have time to check your 02 sensor connections yet? You don't even need to remove the fairing....just remove the bottom screws a nd a couple of the upper one's so that you can just pull the fairing out at the bottom to look up in there......same technique for doing an oil change without removing the entire fairing.
Would be very interesting to see how one that's never had any "fueling issues" as the Brits say is wired up. P.S. Everyone that has had the problems, found that the 02 sensors were plugged in backwards, and switched the connections, please keep posting to let everyone know how your bike is running. Thanks, Craig
yep checked mine.......o2 eliminators still there still running strong!
EDIT: Whoops, spoke too soon! It's plugged in wrong! O2 sensor with black socket was on the bottom hole; sensor with white socket was on the top hole. I'll report back after I have a chance to ride it...
bsd43, Jan 22 2005, 07:01 PMEDIT: Whoops, spoke too soon! It's plugged in wrong! O2 sensor with black socket was on the bottom hole; sensor with white socket was on the top hole. I'll report back after I have a chance to ride it...
Sound like yours are backwards too......wouldn't it be truely amazing if this is the magic fix.......after three years and the soloution is finally found tongue.gif
I've got a friend with an '04 that has the hesitation issue so we're going to be checking his very soon and if they're backwards, switch them over and see what happens.....keeping fingers crossed
ok.....fell into the trap today. figured id pull off the o2 eliminators and plug back in the sensors. if (big if) it is truly correct on the posted assumptions, mine too would have been connected backwards. I took the bike out for a 1/2 hour ride. I still feel a sag in the engine at a steady throttle....approx 4500 rpm. is it as bad as was factory? i dont remember , the o2 eliminators deleted all of it. will it get me better gas mileage? that i dont know , but i figure ill give it a short time of riding before i make my final assumption. ill fill it up tomorrow and run a tank of fuel on a long ride tomorrow and see what i think. right now i'd have to say its BS...maybe after re-adjusting to it ill be able to better decide tomorrow. i just need to see it out of honda's mouth before i believe its true...
767fixer, Jan 22 2005, 05:38 PMok.....fell into the trap today. figured id pull off the o2 eliminators and plug back in the sensors. if (big if) it is truly correct on the posted assumptions, mine too would have been connected backwards. I took the bike out for a 1/2 hour ride. I still feel a sag in the engine at a steady throttle....approx 4500 rpm. is it as bad as was factory? i dont remember , the o2 eliminators deleted all of it. will it get me better gas mileage? that i dont know , but i figure ill give it a short time of riding before i make my final assumption. ill fill it up tomorrow and run a tank of fuel on a long ride tomorrow and see what i think. right now i'd have to say its BS...maybe after re-adjusting to it ill be able to better decide tomorrow. i just need to see it out of honda's mouth before i believe its true...
It's going to lean out a little at cruise no matter what, so there might be a little bit of a flat feeling even if everything is hooked up right. The PC eliminates that because it gets rid of the lean-at-cruise setting that Honda encoded. It isn't really fair to compare the "repaired" bike directly to the PC version. The PC could run the bike so rich that gas pours out the pipe and not worry about passing emission standards of any kind, so the bike should always be better with the PC.
Before you put the PC back on ride it a while, then switch the connectors backwards and see if the hesitation gets worse. That will be the true test for B.S. smile.gif
tbzep, Jan 22 2005, 06:51 PMIt's going to lean out a little at cruise no matter what, so there might be a little bit of a flat feeling even if everything is hooked up right. The PC eliminates that because it gets rid of the lean-at-cruise setting that Honda encoded. It isn't really fair to compare the "repaired" bike directly to the PC version. The PC could run the bike so rich that gas pours out the pipe and not worry about passing emission standards of any kind, so the bike should always be better with the PC.
Before you put the PC back on ride it a while, then switch the connectors backwards and see if the hesitation gets worse. That will be the true test for B.S. smile.gif
i don't have a power commander. just the o2 eliminators. going buy what they posted, if the o2 sensors are hooked up the "right way", that mid range sag should dissappear . for me it hasnt happened yet on my little 1/2 hour experiment
767fixer, Jan 22 2005, 06:19 PMi don't have a power commander. just the o2 eliminators. going buy what they posted, if the o2 sensors are hooked up the "right way", that mid range sag should dissappear . for me it hasnt happened yet on my little 1/2 hour experiment
I should have noticed that you just said o2 eliminators...my bad.
If truth be told, o2 eliminators should not eliminate sag either. The computer still wants to lean the mixture whenever the throttle is at steady state, i.e. crusing. If they are helping, maybe it is because the plugs were backward and sending bad info...and the eliminators just turned off the bad info.
Heck, I don't know...I guess I should mix another drink and shut up. wink.gif
tbzep, Jan 22 2005, 09:40 PMI should have noticed that you just said o2 eliminators...my bad.
If truth be told, o2 eliminators should not eliminate sag either. The computer still wants to lean the mixture whenever the throttle is at steady state, i.e. crusing. If they are helping, maybe it is because the plugs were backward and sending bad info...and the eliminators just turned off the bad info.
Heck, I don't know...I guess I should mix another drink and shut up. wink.gif
if memory servers me.....i believe it uses the o2 sensor reading and tunes down from there....but if the o2 reading doesnt change....yooud figure it may try to tune down harder...you may be right? huh.gif but...... with o2 eliminators on .....it doesnt sag at all. unless the o2 eliminators are set to make the computer believe its already at the correct stoichiometric setting.......now i think im on to something huh.gif may be i should just have a beer and go watch tv rolleyes.gif
imintman, Jan 21 2005, 07:11 PMAs mentioned above, mine were reversed (Black, bottom -- White, top). I switched the cables and did a brief test ride. I'm reluctant to jump to any conclusions but I was unable to detect any 5K surging. I want to ride it that way for a week or so just to be sure.
So you definitely had the surge before?
My bike doesn't have surging that I can detect, but since I've been riding it for two years and I seem to recall it, perhaps I've just "adapted" and can't notice it. I'll check my wiring and see if its the same, but I'll wait until you or someone else says a surge you had before is gone before swapping anything.
Really glad someone figured it out. That takes care of the black eye the VTEC got when it first came out. Something so simple and no one noticed. unsure.gif
OK, just did a ~45 minute run after the swap, on freeways. To preface, the only issue I had with the bike early on (2 years ago) was that when I took it above ~7000 ft elevation, the throttle response was very choppy. The dealer performed a starter valve sync, and all seemed cured. There was never "surging" or "hesitation"...
Well. One thing I did notice immediately today was that there was zero delay in roll-on response from a steady throttle (between 4k and 6k). Since I rode a carburated bike before the Viffer (EX500), I had just thought it was part of fuel injection to have an ever-so-slight delay in throttle response. It definitely felt different.
I'm not going to proclaim that "everything is fixed!!!", because I actually wasn't unhappy with anything. But this is to say that there *was* a difference, and it was for the better.
I didn't get to play in VTEC-land, but I'll test that when I'm on the twisties next.
[quote=bsd43,Jan 23 2005, 07:45 PM] OK, just did a ~45 minute run after the swap, on freeways. To preface, the only issue I had with the bike early on (2 years ago) was that when I took it above ~7000 ft elevation, the throttle response was very choppy. The dealer performed a starter valve sync, and all seemed cured. There was never "surging" or "hesitation"...
Your results sound great so far ! From what this artical says if your's were wired backwards and had "The dealer performed a starter valve sync" prior to swapping them you may need to have the Starter Valves re-sync'ed again to gain optimal performence. At least that's how I'm reading it ? blink.gif Keep us informed ! smile.gif
baileyrock, Jan 23 2005, 12:19 PMYour results sound great so far ! From what this artical says if your's were wired backwards and had "The dealer performed a starter valve sync" prior to swapping them you may need to have the Starter Valves re-sync'ed again to gain optimal performence. At least that's how I'm reading it ? blink.gif Keep us informed ! smile.gif
Yeah, that's what I read too. But, 1) the starter valve sync is done at idle, and 2) the ECU, allegedly, runs in open loop (without O2 input) at idle. So, I don't see how the the synchronization changes, unless the ECU actually takes O2 input at idle...
just got back.....put 100 miles on as a "test". something actually did change. i still feel the o2 sag, but it is very small. on way back to the house it was almost negligable. before rolling throttle out of the sag the bike would lurch. now just pulls smoothly. time in vtec land felt smooth, but i never had a problem there anyhow. did have a bit of a gurgle at just above idle if i let it ride there while trolling through a neighborhood in traffic. never did that before but just may be conditions. 44 friggen degrees in florida at 3:30 pm....what the heck!! im frozenly numb ohmy.gif
767fixer, Jan 23 2005, 03:50 PMjust got back.....put 100 miles on as a "test". something actually did change. i still feel the o2 sag, but it is very small. on way back to the house it was almost negligable. before rolling throttle out of the sag the bike would lurch. now just pulls smoothly. time in vtec land felt smooth, but i never had a problem there anyhow. did have a bit of a gurgle at just above idle if i let it ride there while trolling through a neighborhood in traffic. never did that before but just may be conditions. 44 friggen degrees in florida at 3:30 pm....what the heck!! im frozenly numb ohmy.gif
44 degrees? Dayum that's hot! We had freezing temps yesterday and 40+ mph wind gusts. I had to get on the roof and repair some damaged shingles in that mess!
BTW, That's great that this thing seems to be sorted out now. It's also good to know that guys like me and Hurricane that never had the problem, and others that do have the problem are not crazy!
i never had a problem after the o2 eliminators except for an occasional glitch ( the ol' reboot method). but didnt like it stock. maybe this will work, and maybe ill get some fuel mileage. but i still want a PC III!
767fixer, Jan 23 2005, 05:02 PMi never had a problem after the o2 eliminators except for an occasional glitch ( the ol' reboot method). but didnt like it stock. maybe this will work, and maybe ill get some fuel mileage. but i still want a PC III!
We'd all like a PCIII. smile.gif
It would be nice if the VFR had a switch...one way for max performance, the other way for max fuel economy on long rides to and from the twisties. cool.gif
tbzep, Jan 23 2005, 04:29 PM44 degrees? Dayum that's hot! We had freezing temps yesterday and 40+ mph wind gusts. I had to get on the roof and repair some damaged shingles in that mess!
BTW, That's great that this thing seems to be sorted out now. It's also good to know that guys like me and Hurricane that never had the problem, and others that do have the problem are not crazy!
Wouldn't 44 degrees be great? Tuesday is supposed to be 52 and sunny, do you feel a bad case of the Twistyitis coming on? biggrin.gif
Isn't great to have a perfect Vtec that didn't require any work to get it there?(insert gloating emitcon here)