Car Running Lean - Why?

[90gsxmesaaz]

As you can see in my Vehicle Profile I have an upgraded fuel pump, RC 550, injectors, 2G MAF, FMIC, Buschur AFPR, 56 trim AGP Turbo, and 3 inch full exhaust with high flow cat. In trying to tune my car I noticed that my car seems to run much leaner than other people. When trying to set my low fuel trim I have to have my low settings at 1000 RPMs to +15 just to get it stoich. Most people with the injectors and fuel pump that I have usually have to use negative numbers on their low settings. Any idea why my car is running so lean? I have my base fuel pressure set to 40psi (with the vacuum off and plugged). Any ideas would be great! Thanks!

 

[oldschooltsi]

How are you tunning your car? Do you have an upraged ecu or afc controller....?

 

[90gsxmesaaz]

I am tuning with E-manage which is somewhat similar to a SAFC.

 

[heppm01]

Your 2G MAS is reading about 33% less than a stock 1G MAS would for the same airflow. Your 550s are 22% larger than stock, so you still have about 11% to make up to get back to even - that's pretty close to your +15.

M

 

[justin0469]

also if you have a 255 you should have an AFPR.

 

[90gsxmesaaz]

Yes, I have a Buschur AFPR

 

[justin0469]

ok sorry, lookin back i guess i glanced over it

 

[90gsxmesaaz]

I did not realize that the 2G MAS reads about 33% less than a stock 1G MAS. That helps a lot! Thank you!