when i hit boost my air fuel leans out bad, its in the red! i have a 12:1 fmu(iknow) and i have some check valves in the map sensor line. So i can hit boost with no light but it leans out, i also have a 255 walbro pump. Could it be my map sensor not putting out the right voltage?

 

Mine used to do the same thing. Once I replaced the injectors it never went back to red again.

 

u need an inline pump buddy. That walbro does nuthin to aid the fmu..i'm runnin a 12:1 fmu and inline pump, i'm actually runnin rich even at 8psi

 

my pump should be fine i am only running 8psi. Do you think its the injectors. Stock ls's can run 10 psi all day on stock injectors. i was just woundering if it could be my map sensor not allowing my injectors to pulse long enought

 

rewire the pump. get a relay ($2) and 10gauge wire ($3) and see if that helps. if not, get an inline pump. the FMU will be pulling hellish PSI (fuel wise)...

 

yea id check those injectors out man... also make sure ur checking ur gauge under wide open throttle, thats the only time its accurate. lastly if you fmu is not connected right, or not to a good vac source it may not bu working right for you
mike

 

My car was doing the same thing... So I turned the fuel up.. It got worse.... So I installed the stock fuel pump outta my TT stealth R/T... Still no change....

I post on H-T and they all tell me I'm running too rich, not lean and my autometer A/F guage is ------- me... So I argue with them for like 2 days and finally say "---- it" and I turn the fuel down ( with a VERY LEAN READING A/F GAUGE )... Guess what ??/// They were right the A/F was full of ---- !!! I couldn't even get 1psi without the car falling on it face and running like all out crap, but turned the fuel down and "WOW" " 6psi, no problem", then 9psi no problems, now 13psi, no problems !!!

I've using the AFC hack, but the point is that A/F that seeming worked when your car was N/A is now useless....

Either get a wideband O2 or goto a dyno that has one...

 

this is an new air/fuel gauge the other one did what you were saying it would stay in the lean and this one is perfect yill i hit 3 psi. I am going to buy some dsm injectors, andyone know what generation i need 1 or ?
its an non obd computer.