Originally Posted by
MO LS Noobie
You need to start with a baseline. 128 is actually 0% trim on earlier systems. Disconnect battery cables and jumper the cables together for 10 minutes. This will clear adaptives and eliminate the possibility of the software getting locked up. What fuel pressure are you running? What is the part number of your injectors? Key on, engine off, MAP and BARO should be the same, I suspect the map is off. ECT (coolant temp) and Ambient temp should be the same before starting, I suspect ECT is low. If it is OK, unplug the MAF (if used) and both oxygen sensors. This will keep everything at baseline. Then start engine and see if it is still rich. If it is, fuel pressure is high, injector flow too much, or .bin needs adjusted. If .bin need adjusted, look at injector flow rates. Spark plugs should look sooty if it is rich. Make sure your ignition is all correct. Good luck.