big cammed c5 idle issue

[hodge9386]

I am running a SNS stage 3 235/243 .631/.610 with a ported ls2 intake, ported ls2 tb, longtubes, cattless x pipe, mildly hand ported 243 heads. 99% of my tune is good, it will drive part throttle in 6th gear at 45mph with no bucking, wot is good, it even comes back to idle without searching or any of that crap. The only thing that is bugging me is the actual idle, I want a nice even steady chop but it wont do it. It will start to idle nice and steady then it will sound like its fighting with itself and the engine and car will start shaking. The idle dosent search, it stays right around 900 rpm and my spark is steady at 25/26*. Iv tried close loop idle at 14.7 but my o2 sensors are very erratic so i thought the 17* of overlap was causing the o2s to throw my idle off so I tried open loop and leaned it out to 16.3 which it seemed to like but it still kicks into this quick chop/struggle and shakes the car. Im not sure what to do with it anymore. Any body have some suggestions?

My tune is attached.HC TUNE 4 OL Idle SD.hpt

[Monty]

try playing with your Injection Timing "Normal" and "Make Up" very fine changes.. it will change the chop.. i was able to take mine from a violent shake to no chop at all, and then back to just right amount of chop think i changed mine at something like .53 also iv noticed well here ill give ya my files to check too hard to explain..

but i get a crazy nice chop at 111 engine temp to 133 degrees temp so with the files im post up, you should be able to figure out which way to make yours for the chop you want.. note: all other parameters in the 2bar file is just a base tune file..

but the Injector Timing "Normal" Make Up" tables are what is in my truck today ! what you can hear by watching this video https://www.youtube.com/watch?v=pF_Du7VTxwI when you hear that nice chop there in the video is the 111 to 133 engine temp Injector Timing "Normal" Make Up" you see in the 2 bar file .. note you can hear at first start up cold no chop then hits the 111 to 133 for a very short time, then you can hear it change to a smaller chop..

neways hope this helps peace Edit here is another with exhaust on and a lower idle i think its 650 or 750 with the same injector timings https://www.youtube.com/watch?v=JKpY49iwC-0