Auto Racing: 1995 Mitsubishi Eclipse RS w/T not getting enough fuel with boost, air fuel ratio, fuel pressure regulator

Question
QUESTION: Hi, I have a 1995 Mitsubishi Eclipse RS with an after market turbo, FMU, and a high performance 420A engine in it with lowered compression for the turbo.  When racing I have to start pushing the gas pedal before i release the clutch in order to get my air/fuel ratio at the right level.  Whenever I'm just driving and begin to accelerate as soon as it starts hitting boost my air/fuel gets way to lean.  I've tried changing the vacuum hoses and the fuel lines to my FMU but so far nothing works.  Do you have any idea why it might do this?
         Thanks,
         ED


ANSWER: Do you have anything altering the MAP signal? Is the FMU the only thing you are using for fuel control? What are you using to monitor your A/F's? How much boost are you trying to run? I need some more information about your setup before I can answer you.

---------- FOLLOW-UP ----------

QUESTION: I do not have anything altering the map signal the turbo is an independent unit not controlled by the ECU or electrical devices.  The OBX universal FMU is the only thing that is controlling the fuel, because I am not running alot of horsepower(210-225HP) yet.  I am using an AEM UEGO A/F ratio gauge and I am only running 10lb of boost.  This car does have an intercooler also.  The engine was bored 2 over and eagle rods with forged pistons were installed.  It also had the compression lowered to 8:1.

Answer
Change from the FMU to a adjustable fuel pressure regulator w/ return port and dial in the PSI to acheive the proper A/F's. It is as simple as it sounds. To lean increase the pressure, to rich decrease the pressure. If I remember right the 420A eclipse/Talons already use a fuel return so this should be pretty easy. It would be best to put in some larger injectors while you are at it. The FMU's are a very poor tuning solution, and not responsive or consistant enough for actual tuning in my opinion. OBX makes a universal FPR w/return and it is $95 on ebay.