I'm attempting to troubleshoot an issue with split blm's, it's been awhile since I have last tuned so perhaps I'm over looking something. I have a 383 with a 240/240 .608/.608 107lsa cam, I have a 52mm TB with the IAC port tube mod and 37 pound injectors. The BLM's are maxed out at 108 on one bank and 160 on the other, both at idle and during normal driving. It seems that the longer I drive it the worse it becomes, perhaps something temp related. This takes place in both normal and speed density mode. I had a previous tune dialed in that used straight E85 and then later a blend of E85 and regular gas and there wasn't any issues. Unfortunately I moved to an area where E85 is not available so I am trying to get it to run on straight gas, I have a feeling at the moment it is running extremely rich. I have tried to mess with the TPS volts and adjust the IAC counts but this only seems to effect the blm's at idle not while driving. Any thoughts on where I should begin?

 

Interesting...I was just reviewing a datalog file from yesterday and noticed that the 02 mv readings on my left bank went from normal range around 600-700 or so to just 4 which then made my BLM's split like crazy. Both the normal and the very low o2 readings were during closed loop. How could the 02 readings change this drastically?

 

Change the O2 sensors? maybe?

 

Yea I was thinking of switching them around to see what happens, but they are relatively new. I just find it extremely strange that at one minute it would be at 600-700 and the next stuck at 4. Just doesn't make any sense.