This one has got me stomped. I am one point leaner in AFR during idle and boost. But get this,I have not messed with anything.I have two widebands, an LC1 tied into my ecu for logging, and another seperate unit for display. They both register 1 to 1.5 ponts leaner than usual.

What could be the cause.

Things I have checked:
Base fuel pressure
Fuel pressure under boost
Fuel pump setup
Fuel pump
Voltage

Thanks for your suggestions

 

Fuel pumps failing
Fuel filter need changing
Fuel injectors clogging..

 

air temperature change

 

air/water temp correction maps if any, if not then what he said ^

Wouldn't be a fuel pump/filter issue if he's getting proper pressure under boost. Do you log fuel pressure, or just a mechanical gauge?

 

My fuel pressure is not logged, electric cabin guage. Just rechecked correction maps, they have not changed.

 

recalibrate the sensor and LC-1. My experiences are not great w/ innovate.

 

this is with the Singer EMS correct? your air temp adjustment table may still need some work. It's common for the engine to go richer or leaner when it gets warm out without very careful adjustment of the air temp correction.

 

Thats right, EMS Stinger. The air correction was set and has been working reasonably well up to now. Its just recently I noticed that I was idling at 13xxafr and I normaly idle at 12xx. I didnt pay much attention to it and went a step further and do a logged pull. Sure enough my afr accross the rpm range were about 1 to 1.5 afr leaner. It was the strongest pull I have I have felt at that boost level, and even stopped early because I thought I was over boosting. I dont think my LC1 needs to be recallibrated, it is reading right the car is deffinitely leaner and stronger. My next step will be to increase my fuel trim percentage accross the entire map and I am pretty sure that will solve the prob. I just want peace of mind by knowing what caused the sudden change of afrs