I am getting really tired of this split BLM thing.. My BLMs are off by ~15-20. I thought I had an exhaust leak, and found that my driver side manifold had a couple bolts that were a tad loose. So I tightened them back up, and to my dismay, the split BLM problem was still there. I took her into a muffler/exhaust shop, and they checked for any exhaust leaks.. there were none.

My O2 sensors are brand new.. and were installed no problem.. The cam I am using isnt too harsh-

222/230 .542/.563 112LSA

so I dont think that could be it.. any suggestions??

 

I've seen this a lot, and not much discussion. I've been told that you can just set the threshold MAP value for BLM update/learn a little bit low and prevent BLM update at idle type conditions and erase the issue. I've struggled as well, with often the case I've just disabled CL entirely to avoid crazy BLMs with big cam motors.

I'm sure there's a better way, anyone? I guess this only applies to dual-O2 like the LT1s right?

 

ive seen some things on the WEB about the issue having to do with the way air is directed from the IAC passages into the plenum cuasing un even fuel distrobution. now the fix i would look into is the cylinder to cylinder fuel trim. if this problems is occuring everywhere the engine operates. if its a at idle issue id find out who else has straightned this problem out.

check via the lt1edit tunnign FAQ i remeber reading something there a while back.

 

I'm leaning towards the theory that it is an idle only problem. My buddy's LT1V had stupidly different BLMs at idle, but all of that cleared up once we were under way. Even during off-idle conditions sitting still the integrator & BLMs were pretty close side to side.