This weekend was the first long ride I've taken since I gutted my exhaust and got a PC3+Coyze's map. On Friday, I rode up Carson Pass (a little over 8000') when the temps were in the upper 50s and all was well.
This morning, as I ascended up Monitor and then Ebbett's pass coming home, the bike was running like crap! I first felt something amiss at about 6500' with the temps in the mid 40s. Things got even worse as I ascended to the 8700' pass (temps stayed about the same). The bike would idle around 600-700rpm, barely staying running.. the VTEC transition was enough to jerk my body front and back, huge flat spots followed by surges, huge power loss, etc! I was seriously worried something was *really* wrong.
I have done this same ride pre-PC3 and had no problems (other than less power at high elevation, which is completely expected).
Going downhill, it was mostly fine since I wasn't on the gas much. Once I got down to 3000' or so and the temps had risen, I came to a stop and the idle was normal. I ran it through the rev range and it once again felt great....
Is this behavior expected? or is it indicative of something else wrong?
I am running a PCIII with Cozye's map and Staintune exhaust. I was riding at about 5300 feet of elevation about eight days ago and noticed the same thing, but not as severe as you describe.
At higher altitudes and cooler temperatures the VTEC transition was very abrupt under acceleration. When I came back down a few thousand feet it was just fine.
It's normal for the idle speed to drop at higher elevations. I keep mine set around 1400-1500 and it will drop down to as low as 900-1000 around 5300 feet. I would do this even before I installed the PCIII. Also the loss of power at elevation is pretty normal.
[image: View Post]johnmark101, on May 25 2009, 08:14 PM, said:
I am running a PCIII with Cozye's map and Staintune exhaust. I was riding at about 5300 feet of elevation about eight days ago and noticed the same thing, but not as severe as you describe.
At higher altitudes and cooler temperatures the VTEC transition was very abrupt under acceleration. When I came back down a few thousand feet it was just fine.
It's normal for the idle speed to drop at higher elevations. I keep mine set around 1400-1500 and it will drop down to as low as 900-1000 around 5300 feet. I would do this even before I installed the PCIII. Also the loss of power at elevation is pretty normal.
Thanks, this makes me feel a little better. When I installed the PC3, my idle dropped from ~1400 to ~1100-1200, don't know if that was normal, but it wasn't a big enough change for me to do anything. With my idle being lower, it obviously allowed it to drop down to below the 'idles fine' region once I hit the high elevations.
There's an idle screw on the "wheel" where the throttle cable attaches to the throttle bodies, right?
When my bike is only at 165-170 the vtec is always abrubt. Dosent it kick in at 160 or is it 170? My bike is stock with remus exhaust and it dosent run good and smooth till 170 and above.
[image: View Post]SkeeBoy, on May 25 2009, 09:33 PM, said:
When my bike is only at 165-170 the vtec is always abrubt. Dosent it kick in at 160 or is it 170? My bike is stock with remus exhaust and it dosent run good and smooth till 170 and above.
VTEC kicks in at 150�... I've had this bike for 7k miles, I know what it feels like (and how it feels different) throughout the temp range. I'm one of the guys that doesn't mind the transition at all... seems to be mostly noise... but this morning, I assure you, I was jerked harder than ever before. It was like someone cut the throttle to zero, downshifted, then twisted the throttle to 100%.
[image: View Post]klinquist, on May 26 2009, 05:07 AM, said:
[image: View Post]johnmark101, on May 25 2009, 08:14 PM, said:
I am running a PCIII with Cozye's map and Staintune exhaust. I was riding at about 5300 feet of elevation about eight days ago and noticed the same thing, but not as severe as you describe.
At higher altitudes and cooler temperatures the VTEC transition was very abrupt under acceleration. When I came back down a few thousand feet it was just fine.
It's normal for the idle speed to drop at higher elevations. I keep mine set around 1400-1500 and it will drop down to as low as 900-1000 around 5300 feet. I would do this even before I installed the PCIII. Also the loss of power at elevation is pretty normal.
Thanks, this makes me feel a little better. When I installed the PC3, my idle dropped from ~1400 to ~1100-1200, don't know if that was normal, but it wasn't a big enough change for me to do anything. With my idle being lower, it obviously allowed it to drop down to below the 'idles fine' region once I hit the high elevations.
There's an idle screw on the "wheel" where the throttle cable attaches to the throttle bodies, right?
The idle adjustment is just above the clutch cover, behind the right fairing. It is a black knob with a phillips head screw in the center. Put the bike on the centerstand and let it run until it reaches operating temperature.......then adjust the idle as needed.
[image: View Post]klinquist, on May 25 2009, 11:48 PM, said:
VTEC kicks in at 150�... I've had this bike for 7k miles, I know what it feels like (and how it feels different) throughout the temp range. I'm one of the guys that doesn't mind the transition at all... seems to be mostly noise... but this morning, I assure you, I was jerked harder than ever before. It was like someone cut the throttle to zero, downshifted, then twisted the throttle to 100%.
I know you said your T-stat is good, but my bike has the exact same symptoms when it has warmed up then falls below 160 deg.or so (bad t-stat) because of cooler outside temps. The Vtec transition is horrendously ruff to an extreme level, this is the ONLY time my vtec is ever ruff!
I don't run a PCIII at all either. This may have zero to do with your bike, but I could understand someone's complaint about Vtec transition if this is how theirs felt and think engine temp and a ECU glitch is the cause for those how have ruff transition on a stock bike! :cool:
On the other hand, doesn't running a PCIII w/no 02's hooked up remove the bikes ability to adjust A/F ratios based on Altitude? :blush:
[image: View Post]Baileyrock, on May 26 2009, 10:42 AM, said:
On the other hand, doesn't running a PCIII w/no 02's hooked up remove the bikes ability to adjust A/F ratios based on Altitude? :blush:
BINGO! +1 +1 +1
There's your problem right there.
I don't think our engines have an air pressure sensor (do they?) but running a PCIII means you are running the exact same amount of fuel at sea level and 10,000 ft, which is a problem.
However, you're experiencing the same problem anyone with a carbureted engine has unless they change their jet size before entering them mountains. This is not a new experience...
[image: View Post]Baileyrock, on May 26 2009, 07:42 AM, said:
On the other hand, doesn't running a PCIII w/no 02's hooked up remove the bikes ability to adjust A/F ratios based on Altitude? :blush:
Mine idles pretty low (800-900 rpm) once I get above 5,000 feet or so, but I've never heard this could be the cause if a bike is running a PCIII and O2 Eliminators. I always thought it was the Map Sensor's job to sense distance above sea level and adjust its output voltage. Having said that though, mine tests fine and my bike still idles low at high altitude. :blink:
[image: View Post]Ryanme17, on May 26 2009, 11:07 AM, said:
I don't think our engines have an air pressure sensor (do they?)
The MAP sensor is used to give the ECM a base line for pressure when you first turn the bike on. That is how almost every EFI system without a dedicated BARO sensor works.
Thats some pretty high altitude. The downside of fuel tuning on a bike is that you run into problems like this with extreme atmospheric changes.
The stock Honda map is tuned for a wider range of conditions, which is why you can gain a little power by refueling the bike because you give it a more optimal tune for that environment. The map was made and tested at 800 ft elevation.
In the cold, your wax unit might kick in a bit and make the bike run richer, that on top of the fact that the map is 10-15% richer in a lot of places and you were at 8000FT!! would indicate that you were running too rich for the environment.
HS could probably speak a lot more about riding at high elevation. I know that when I had my VFR I would notice it running a bit off at elevations from 3k-5k ft, but that was even with the stock map.
my recommendation would be to put in a 0 map when running at elevations above 5500 feet. I've tested that map at 5500 feet and it should be fine at those elevations for short periods of time.
richer for short times is not harmful. rich fuel for a long period of time can cause "cylinder wash" and dilutes the oil film on the cylinder walls. On the other hand running at over lean conditions are bad!!
[image: View Post]cozye, on Jun 1 2009, 06:24 AM, said:
Thats some pretty high altitude. The downside of fuel tuning on a bike is that you run into problems like this with extreme atmospheric changes.
The stock Honda map is tuned for a wider range of conditions, which is why you can gain a little power by refueling the bike because you give it a more optimal tune for that environment. The map was made and tested at 800 ft elevation.
In the cold, your wax unit might kick in a bit and make the bike run richer, that on top of the fact that the map is 10-15% richer in a lot of places and you were at 8000FT!! would indicate that you were running too rich for the environment.
HS could probably speak a lot more about riding at high elevation. I know that when I had my VFR I would notice it running a bit off at elevations from 3k-5k ft, but that was even with the stock map.
my recommendation would be to put in a 0 map when running at elevations above 5500 feet. I've tested that map at 5500 feet and it should be fine at those elevations for short periods of time.
richer for short times is not harmful. rich fuel for a long period of time can cause "cylinder wash" and dilutes the oil film on the cylinder walls. On the other hand running at over lean conditions are bad!!
[image: View Post]cozye, on Jun 1 2009, 07:24 AM, said:
Thats some pretty high altitude. The downside of fuel tuning on a bike is that you run into problems like this with extreme atmospheric changes.
The stock Honda map is tuned for a wider range of conditions, which is why you can gain a little power by refueling the bike because you give it a more optimal tune for that environment. The map was made and tested at 800 ft elevation.
In the cold, your wax unit might kick in a bit and make the bike run richer, that on top of the fact that the map is 10-15% richer in a lot of places and you were at 8000FT!! would indicate that you were running too rich for the environment.
HS could probably speak a lot more about riding at high elevation. I know that when I had my VFR I would notice it running a bit off at elevations from 3k-5k ft, but that was even with the stock map.
my recommendation would be to put in a 0 map when running at elevations above 5500 feet. I've tested that map at 5500 feet and it should be fine at those elevations for short periods of time.
richer for short times is not harmful. rich fuel for a long period of time can cause "cylinder wash" and dilutes the oil film on the cylinder walls. On the other hand running at over lean conditions are bad!!
OK so what should the rest of us do that live above 6000ft? I was running tinyminds map. Well way too much fuel not enough air. Looked like a Dodge diesel truck chipped on level 5! BLACK SMOKE would just poor from my exhaust. Other than the James Bond effect it didn't seem to do anything. Im now running the stock TwoBrothers slip-on map. I have catless headers, removed all emission control, pair valves gone and modified the air box with a K&N air filter. The stock map seems to work great but I can't believe there isn't a hight altitude map? Can somebody PLEASE be the 1st? I would love to but don't have the $$$$$$$$. Any suggestions?
Thanks Itwrx
Make a copy of Cozye's, and/or Tinymind's map, and dial the fuel out incrementally, until the bike runs well again? You can do that on your own, or pay a shop with a dyno to do it for you?
When I had my 99' vfr, I was living in Denver(5000ft) and would ride in the mountain areas almost every time I when riding (so anywhere from 5000 to 14000)......... It was stock, and I never had a lick of trouble with it (100k)....... Monk
[image: View Post]itwrx, on Jun 1 2009, 11:10 AM, said:
OK so what should the rest of us do that live above 6000ft? I was running tinyminds map. Well way too much fuel not enough air. Looked like a Dodge diesel truck chipped on level 5! BLACK SMOKE would just poor from my exhaust. Other than the James Bond effect it didn't seem to do anything. Im now running the stock TwoBrothers slip-on map. I have catless headers, removed all emission control, pair valves gone and modified the air box with a K&N air filter. The stock map seems to work great but I can't believe there isn't a hight altitude map? Can somebody PLEASE be the 1st? I would love to but don't have the $$$$$$$$. Any suggestions?
Thanks Itwrx
Top performance would be to tune a leaner than stock map or a custom map for those low oxygen conditions. The problem will be however than one day you won't be thinking about it and you will ride down the mountain into town at 1200 feet and will be excessivley dangerously lean. Honestly, like the guy says above I'd just stick with the stock fueling and setup and sell the power commander.
[image: View Post]SEBSPEED, on Jun 1 2009, 10:36 AM, said:
I thought O2 sensor elim's were mandatory w/ the PC3 install as well?
not mandatory, but recommended. The o2 sensors aren't a wideband sensor on these bikes so they don't continually adjust fueling. They only put the bike into a lean mode while cruising at part throttle. Having the o2 sensors in with the pc3 throws the pc3 map off every time it goes into this lean mode.
End of thread · 24 posts recoveredWayback Machine snapshot 12 Apr 2010