I'm working on an SD tune on a 2000 SS, 6 speed. There's something forcing the car to run lean in the upper left portion of VE table. Take a look at this picture to see what I mean:

I followed the WS6Snakeater write up. I'm using a WB and seems like no matter what changes I make to the VE table, I still end up with a histogram that looks like the one in the picture. Any ideas?

Drew

 

Make sure DFCO isn't enabled.

 

What's the best way to disable DFCO? I changed the "DFCO Enable Normal" Temp to 250, but that didn't seem to have any effect. Should I the "Speed vs Baro" and "TPS vs RPM" tables (using HPTuners)? I haven't worked with these tables before.

Thanks.

 

You didn't unplug your MAF. If you did unplug it, then you have a vacuum leak. If that isn't it, you may be really screwed...

You can disable DFCO easily by making the DFCO enable temp 258 degrees. DFCO won't do that though.

 

I have never seen anything like that...weird!

 

Post a pic of your fuel trims.

 

Well, I disabled the DFCO, but that didn't change the look of the histogram I posted earlier. The MAF is unplugged, so that's not what's causing this weird condition. As an aside, the bucking/surging I get is much worse in SD mode. I also pinpointed the exact situation where the surging occurs: right in between where the car is running lean (the peak in the upper left portion of the histogram) and where it's running rich (the valley running down the middle). Makes sense. At that area, the car is probably confused about the fueling and causing the surging. If I can figure out the peak and valley situation, I bet my surging goes away.

So, is there a magical button I can push to clear this up?