| Author | Message | ||
     Anonymous |
Hi Buellers, Here is what I have. 1999 S3 with NRHS thunderstorm stage 2 heads with forged pistons, heads milled and combustion chambers machined. I have many miner mods also but still have the stock cams. I am using the race ecm and am using a Super Trap muffler with 20 disks. The bike ran very well for 5000 miles but now has a hiccup about 3000 rpm when accelerating hard. This happens severally when the bike is hot. Not so much when it is cold. If I roll out of the throttle the bike lights back up as if nothing happened. I haven't checked the air temp and head temp sensors when the bike is cold to make sure that isn't the problem. This started very slowly and got worse over time. I just changed the tps and the bike runs no different. When the bike cools down I will check the temp sensors to see if that tells me anything. Thanks, Steve | ||
| Hootowl |
Does it feel like it's leaning out? Did you check you intake seals for leaks? | ||
| Tirebiter |
When the motor is cool there is no bog or a very small hichup. When the motor warms up it seems to have no fuel when it gets to a certain rpm. I haven't checked for a leak since the bike idles very well, so I am thinking more on an incorrect output from the ecm to either the injectors or the timing due to an inaccurate or failing temp sensor. I will check the intake the next time I start the bike. I want to wait for the bike to get to room temperature to check the temp sensors with ecmspy. That will happen tomorrow morning. Thanks, Steve | ||
| Kalali |
Try a TPS reset before doing further troubleshooting. | ||
| Tirebiter |
I did do a tps reset after replacing the tps sensor. I am going out to the shop soon and will redo the reset. I need to watch ecmspy while going through the complete range of throttle motion which I didn't do before. The bike runs exactly like it did before the tps reset and that makes me think that the problem is in the heat sensors. I have been wrong before. Thanks, Steve | ||
| Phelan |
If you're still using stock cams and had the heads milled to deck to squish, you are likely running higher compression than before and need to retard your timing if you didn't do so during the rebuild. My Uly build had a similar issue, which didn't present itself until I went on an all-day ride with my wife on the back. Too much advance and a lean condition made the bike get very hot, which through the course of the day led to the intake valve seats moving and losing their seal when closed. Mind you, the lean condition didn't show itself on the dyno tuning, because we were reading it out of the tail pipe, not individual O2 bungs for each cylinder, which would be ideal. Judging the spark plugs, only the rear cylinder was running lean. In my case, the seats started disintegrating, so I'm replacing them now. But I have 1.900" intake valves, which made the seats much smaller, whereas you likely have 1.840" if your heads are stage II. (Message edited by phelan on July 18, 2015) | ||
| Tirebiter |
Thanks Phelan - I am running some retard that was recommended by Dan, maybe 1 degree. How much retard are you using? I do hear spark knock when I lug the motor off idle, but only then - I try not to do that. Just checked engine temp sensors with engine at room temp. Room is 81F, engine temp sensor reads 24C (75.2F) and air temp reads 27C (80.6). Need new engine temp sensor. Checked tps and have full range and smooth operation. I may be getting somewhere. Thanks, Steve | ||
| Two_seasons |
I wouldn't worry about 6 degree F at the ETS. At full heat soak of engine/trans, that would be about 15 degrees F difference. Not enough to worry about IMO. I'd be wiggling the ETS lead and make sure it's not shorting or has but a couple of strands of copper left. ETS is notorious for shorting in the deep well config! | ||
| Phelan |
I would retard it another degree or two personally. I had retarded mine about the same as you but it wasn't enough. Problem is that I'm building an XB and there is very little charted territory in the route I'm going, at least that I've found. I know there are other builds somewhat similar but I haven't found any info on tunes for those bikes. I have custom headwork with welding, 10* 1250 kit, ported manifold, and CAT3 cams, but stock exhaust. | ||
| Tirebiter |
I have a engine temp sensor ordered. Bike runs normally as long as I drive conservatively. Went to a bike nite at a local tavern last nite. Bike only hiccuped once. Steve | ||
| Kalali |
Out of curiosity, how do you retard the timing on FI bikes? ECMspy and the timing tables? | ||
| Hootowl |
By rotating the timing cup, I believe. | ||
| Tirebiter |
Hootowl is right. Watch the ecmspy page while rotating tire forward with bike in a tall gear. Helps to have plugs out. I rotated the timing plate to have the ignition fire when the timing mark is slightly to the right of vertical mark(retarded or later ignition timing). In my case the mark was about 3/32" to 1/8" off center. | ||
| Hootowl |
Yep, sorry, timing plate. I think the cup moves with the crank. I've never actually looked at one. I haven't had timing issues with any of my Buells. | ||
| Tirebiter |
When I was rebuilding my bike 5 years ago, I powder coated the frame and did many mods to the motor. In my talks with Dan from NRHS he mentioned that they had a billet timing cup so I ordered 1. What I didn't realize was that it was for a carburated bike, not fuel injection (2 windows instead of 5). I think Dan had me confused with someone else and I do not blame him for anything. I spent 3 months trying to get fire to the bike. Changed wiring harness, disassembled bike twice to make sure I wasn't having a problem with a faulty ground caused by the powder coated frame. Changed ecm and several sensors trying to find the problem. Only when I happened to see the original fuel injection cup did I notice the difference in the number of windows. Put the original cup in and the bike fired. Have mercy!! | ||
| Kalali |
Got it. We are talking about static timing and I was thinking dynamic timing tables. Anyone ever messed with dynamic timing? | ||
| Tirebiter |
Found the problem. I had been using some Pulstar spark plugs that used a large gap. I paid over $40 for those plugs and had only had them in for 2000 miles when problem started. I can only imagine that the increased gap was messing with the ecm causing the hiccup.(?) Changed the plugs out for some iridium plugs and all is well. Thanks to everybody for there input. Steve |
