08 VFI K9 What i've learned about bad rear sites

[Corey]

I have a lightly modified (600 cam, Sachs headwork, s&s dual runner, big radius 2 into 2) k-9. Runs good but for some reason I've always had the rear sites out of perameters problem. I had the exhaust installed before I picked the bike up brand new. Other mods came as time went on. Checked wiring and checked for air leaks smother things. I would plug in the computer, go into pro tune 2 software and the real cylinder fuel map was way out of perameters but only in certain ranges. Basically up to 18% throttle position up to around 1800 rpm. Couldn't figure out why! So this year at Sturgis I stopped at 5 dyno tuners and none of them messed with the s&s tuning. When I finally got to the s&s booth and explained what was going on he figured it out about instantly. He plugged in to the module, looked at the maps, went and balled up a few rags and with the bike running put the rags over the front and rear exhausts as he was watching the screen. The rear cylinder being the shorter pipe was sucking some air back in (as they do) far enough to be read by the O2 sensor thus telling it to dump more fuel causing the bad rear sites. Solution - get a nice 2 into 1 pipe or what we did for now. We just forced the fuel injection to run off the base map at those areas comprised and left the rest closed loop. Ran perfect the entire Sturgis trip. What ever you do save your original map. Yes I speak from experience or lack of. Long post - had a few extra mins at lunch and thought I should share.

 

[HMAN]

This is great nfo. Thanks for sharing. I know its gonna help some other folks.:2thumbs:

 

[chacha]

Good scoop...thanks for writing it up man!

 

[Jwooky]

Great info.

Where did the map your using come from? Custom, or a Map you found somewhere.

How did they force base map only in certain points?

 

[Pond Bear Swilley]

So what you are saying is to short of a pipe on Fuel Injection with exhaust reversion can indicate/read as lean condition at the 02 sensor?

Good to know! Thanks fo the info. :2thumbs:

 

[Th3InfamousI]

Yep!! Short pipes will get you everytime. Espeically uneven short pipes.

I have the FSD exhaust with the shorter pipe in the rear my front plug is spot on golden brown and my rear shows lean. Not sure about your pipes but the FSD I would say the length of the front pipe if straighted out is about 2x as long as the rear pipe straighted out.

I have contemplated stuffing a short baffle in the rear to mitigate the rear running lean.


Price you pay for looks I guess.

 

[Th3InfamousI]

So what you are saying is to short of a pipe on Fuel Injection with exhaust reversion can indicate/read as lean condition at the 02 sensor?

Good to know! Thanks fo the info. :2thumbs:

Just a hunch but I have a feeling your not who you say you are. Carry on however it is the internet - Wild Wild Web :2thumbs:

 

[08mastiff]

Just a hunch but I have a feeling your not who you say you are. Carry on however it is the internet - Wild Wild Web :2thumbs:

Curious myself on that one.......time will tell.

 

[Corey]

The map? Thats another learning experience i didnt need to have. Here's the little story. So the bad rear sites problem i thought i could fix in the software but you can't fix something if you don't know the problem. Before I started I thought I saved my map that was in there but somehow it wasn't saved. The changes I made richened up the rear way too much and i was at a standstill. I called the place that tuned it and they crashed their computer and my original map was lost. I had to laugh! So I brought them the bike and explained the problem as i did the S&S guy. They had no clue. They went back and forth with S&S about one thing or another at least that was their story. What it came down to was i told them they had to wipe the mogule clean and load a new map. I told them to have S&S send them one. Finally the day before leaving for sturgis they had a map in and it ran ok. So i guess its a map from S&S. S&S did say just load the one for the 124 that has the 640 cam but that seemed extreme but it would learn. All this still wouldnt of solve my issue. The guy from S&S that i met in Sturgis saved my map cuz they didn't have one like it. Maybe they will put it on their site or i can send you a copy of mine. As far as setting the mapping targets you do that in the Pro Tune software. Of course he made it look easy. Once you bring up your fuel maps you can look at the values thats it out of range. Then you can bring it up in a chart and select the cells you want to change and click on them and a small drop down menu appears. And he set those areas on "stioch" which has it run off the base map in those ranges you selected. Sory its not a tutorial. Before you try anything SAVE YOUR FILE!

 

[Corey]

I am calling S&S in a week or two and were going to merge my maps and hopefully not erase them this time. He said he'll talk me thru it. I'll try to record the call so i can write up what to do. Its easy to load the software and go look around. Make sure you go to the advanced mode. Thats where you'll see everything.

 

[erldawg]

Thanks for the info Corey excellent post...I did save my original map... It's time to take a look and see what's going on...