I have been getting a SES light while cruising, so I scanned it. The code turned out to be left and right o2 rich. I in the lot I noticed that everything looks fine until I cruise and the car goes to fuel trim cell 6. When it goes to cell 6 the long term blms go straight to 160, and short term blms goto 108 on both sides, the o2 readings goto 900 and I get about 6* of knock. After about a minute of cruising a SES light is set. If a give it more gas the o2's to back to reading right and the blms are around 130 in all other cells. Is there something in the tune thats causing this or what? Thanks for the help.

About the car: I have converted to a 94+ computer, dynotuned, custom cam similar to cc306 on a 113, LT, CAI, MSD 6al, M6

 

Could be the tune. Without seeing a datalog anything would be pure speculation.

 

Agree with Vince, in cell 6 for a stock tune you're RPM's s/b between 1200 - 2000 and MAP should be between 30 -50 kpa. When you give it gas you may be changing RPM and/or MAP and moving to another cell or the failure just clears by itself. See if your log shows the MAS air flow significantly dropping when you hit cell 6. A low MAS gms/sec reading or one of the MAF calibration tables messed up for specific frequencies could cause lean conditions.. In your post you have BLMs, cell, knock and O2 readings so you have some kind of data. What tool are you using to? What code are you throwing ?

 

I am using datamaster to log and the codes are 45 and 65. Well I started looking at the tune and found in the VE tables and might of found my problem. In the area around cell 6 there is a all 99.6. I'll find out if this works later on today. Thanks for your help

 

Jason, are you running SD ? edit...sorry just noticed you are a '93..

 

Sounds like you found it. It's unlikely your engine has a volumetric efficiency of 99.6% in that RPM and MAP range. ;-)

 

Too high a Ve will make the thing run rich not the other way around. A ve of 99.6% is saying you have 99.6% of the volume of air that will fill each cylinder trapped in every cylinder. While i agree that will not be kosher for this type of situation, that will cause overfueling not running super lean.

Does the blm go crazy on both sides or just one? What is the actual map reading, the fuel injector duty cycle etc. Does the trend continue if you drive the car faster or in a diff cell say 70mph. Sounds like a fuel pump, vacuum leak or a bad sensor on the intake or engine temp side of things.

Post a datalog, and you'll get better answers from everyone. If i was you when you get the problem figured out i'd spend some real quality time with ve master and get the fuel trims fixed for part throttle.