| Author | Message | ||
     Buell_41 |
First I'd like to thank Al at Amerian Sportbike, Keith Thrash at DarkHorseMoto, a buddy of mine in Tulsa as as well as the BWB community for their massive effort to help me resolve this issue. All of them provided invaluable help, with out which, I would have got rid of my bike altogether. For those who haven't been a part of this, the short story is that my bike was performing very poorly. It was missing badly on steady state rides, surging at idle, and fuel mileage went down about 15%. I replaced the following parts in an effort to resolve the issue: Head temp. sensor Fuel pump Ingnition coil 90% of the fuses (discovered during testing that most of the fuses that the dealership had sold them bike to me with, were in some cases, rated for double what they should have been... AKA a 20A fuse was where a 10A fuse was supposed to be) While some of those things may have helped, we're not sure if they had any real bearing on resolving the issue. Just FYI, throughout this whole process, we did what diagnostic work we could with a DVOM and the drill down procedures in the service manual. I downloaded ECMSpy and Mr. Thrash was kind enough to loan me his cable. Initially, I observed 3 things. First, the AFV was around 115. Second, the software indicated that my o2 voltwage was .02V. I learned later that this was WAY out of range. Third, the voltage was did not move. Al had me do a series of tests where I disconnected the o2 sensore and forced in values of 100, 115, 125 and 95. After each change I'd take it for a ride and gauge the change. This is what I found: Reference point scale 100 (no problems, bike runs smoothly at all rpms accel./decel.) 0 (head about to snap off, rough to no idle, dies on decel.) AFV at 105 - no o2 - (50) improvement - bike still exhibits missing symptoms at 30/3k/2nd steady state but pretty much disappears after 3500. The "spikes" when it misses are lower but the frequency is about the same as pre-tesing. At 4k it will miss every so often and range from feeling like a bump in the road to front forks momentarily compressing. Accel is slightly uneven (very tolerable) Decel also slightly choppy (tolerable) surges at idle AFV at 100 - no o2 - (80) improvement - bike still exhibits missing at 30/3k/2nd steady state but pretty much disappears after 3500. The "spikes" when it misses are lower but there are more of them and more closely match the engine vibs. Little to no missing at 4k... almost negliagable. Accel is even. Decel is slightly choppy choppy. surges at idle AFV at 125 - no o2 - (85) improvement - bike still exhibits missing at 30/3k/2nd steady state but disappears at 3200 and up. The "spikes" have the same amplitude as as the 100 AFV but the frequency is much further apart. Noticibly quieter engine running. Accel is like SILK Decel is very very smooth Slight after-firing on decel/idle After a 4k steady state run, bike wants to idle at 2100 (not surprising due to fueling) surges at idle AFV at 95 - no o2 - 200 decrease - misses everywhere. Very lathargic accel.. dies at idle. Pronounced valvetrain noise. Very "viby". Noticable decrease in power in midrange. Accel is WAY WAY choppy... awful. Decel is like AFV at 105 (funny how these last two conditions make complete sense when looking at my fuel map. It already cuts fuel on decel so this feels normal but since in can't enrichen the mixture on accel. its all screwed up) Doesn't idle We did this because according to Al, without the o2, we force the bike to stay in open loop and never adapt the AFV. Doing this attempted to determine if the problem was in the open loop or closed loop. In talking with Al we discovered (we think) that AFV is driven by EGO correction. So it goes O2 sensor, then EGO (constantly updating rich lean rich lean etc.), then AFV (which is adaptive or average fuel value). The bike learns with the EGO but RUNS on the AFV. Also, there's a difference between closed loop and closed loop learn. Our bikes can be in closed loop but not learning... AKA warm engine at idle is in closed loop but isn't updating the AFV thus not learning. In closed loop it is reading the instanteous O2 values to keep the engine running, but doesn't update the AFV. I think it truly does only learn above 2k (my opinion). Sooooo... just a guess at this point: Open loop: ambient to whatever the bottom temp range is of the O2 Open loop: enters this mode again when rpms > 5k Open loop: in WOT Closed loop: engine temp. at bottom range of o2 or engine at operating temp. (both below 2k rpm and no load). Closed loop learn: 2-4k (or 5k for 9s) steady state only. If you accelerate, it goes into open loop for the duration of the acceleration. If you then were stable at the higher speed, it would go back into closed loop learn. This is because in order to accelerate it must slightly (and momentarily) enrich the fuel beyond 14.7:1. The whole reason for an O2 is to get that 14.7:1. There's a time element to AFV that neither Al or myself can't figure out. We don't know what the bike to initally enter closed loop and we don't know how long it takes the EGO to update the AFV. For those of you with VDSTS, the AFV is the number you see with the bike on but not running. When the bike is idling, the numbers you see are the EGO which should be wildly varying from ~.1V to ~.95V. A year or so ago I re-routed my vent lines to the outside and terminated them with one of those mini K&N looking bullet filters. So after all this testing, I'm looking around for shorts and by accident, I discovered that that filter was completely blocked. The pressure could build up enough to leak out between the fittings and the rubber hose, return to normal, then build back up and repeat. This is what was causing the surging at idle. I removed the filter, plugged the o2 sensor back in, did my test ride, came back and plugged in to ECMSpy. Sure enough, AFV was at 105... perfect. One thing solved but it still ran poorly and missed... and the o2 voltage was still messed up. At this point, we really didn't know what a .02V meant other than it was SO out of range that we thought it had to be the ECM. Purchased one from American Sport Bike. With the new ECM in place, I did a TPS reset, connected the o2 and vwala!! o2 came alive and boy did it ride good. Just on a whim we decided to test the old ECM by "sucking the brains" out of the new one and burning them into the new one. With the new one in, and new brains burned in I checked the o2 voltage and sure enough... no oscillations. Thinking we converged on some A to D problem with the ECM, I joyfully put the new one back in. But wait... the voltage was stuck again!!!! More loom tests that finally ended in me replacing the o2. This seems to have corrected the oscillation problem but I don't really know what the problem was... I may still actually have whatever caused this and it'll come up again. I may have just pushed the correct wire and its working... I've replaced just about all I can for just working on it in my garage... Comments welcome. Whats your take? Karsten | ||
| Preybird1 |
My bike did this same thing drove me nuts, I replaced so many things as you did to no avail, Then on a chance we happened to have a race ecm handy and we put it in and it was golden from then on. Parts replaced O2 sensor used bosh/chevy replacement sparks and wires coil swapped for test only! rear head temp sensor air temp sensor. borrowed race ecm borrowed race intake I had an exhaust stud break and when re installing the headers the o2 wasn't tight enough and vibrated out, Which started the problem i was having. This may sound weird but when i pulled the old ecm i smelled the connectors and it smelled like burnt plastic, We installed the race ecm and it ran better than ever. So the o2 sensor some how shorted the ecm input side pins when it came out and the ground was lost, So it was not reading correctly. My bike ran exactly like you have described, after all this it is running well to bad its snowing here! | ||
| Bombardier |
Had similar issue. Replaced the standard NB single wire O2 with a 4 wire (heated/grounded) NB O2. I believe the running issues are in part caused by the fouling of the O2 sensor at startup caused by an over rich mixture and insufficient temp to adjust the O2 to compensate and oil from the the vent lines fouling the O2 and the AIT. |
