Here's my setup:
b18c5
je 9.6:1 pistons
fmu
S-AFC II
stock injectors (for now cause I'm keeping it to 7lbs)
AEM fuel rail/reg
t3/t4 turbo
Profec-B
Walbro 255

My problem is no matter how much I richen my fuel map right as the turbo starts to spool like at 1 lb. my engine starts to go a little lean then as I start to make 3 or 4 lbs. it richens up to right where I want it. I am pretty new into the world of turbos so any suggestions would be great. I have allready checked the pressure lines going to my fmu and also my fuel pressure.

 

Thats the problem with FMU's, they take a second to add pressure so sometimes you get a delay in fuel delivery. Might want to try and put in a bigger ratio disk (ie. 5,8,10,12:1 depending on whats in there now) and then use the AFC to fine tune you a/f.

 

I have a 12:1 disk. The FMU worked fine for a short time and just today and yesterday I ran into this problem out of the blue. Could the problem be that my boost gauge, Profec and FMU are all T'd off of the same pressure line?

 

vacuum will be unlikely the cause of it, although you may want to try to run the vacuum for the FMU independently and see if that solve any.

stan