when i hit boost
 

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?

Re:when i hit boost
 

how much boost are you running?

Re:when i hit boost
 

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

Re:when i hit boost
 

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

Re:when i hit boost
 

what are you talking about?...how would the walbro not helo the fmu?

Re:when i hit boost
 

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

Re:when i hit boost
 

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)...

Re:when i hit boost
 

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

Re:when i hit boost
 

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...

Re:when i hit boost
 

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.

Re:when i hit boost
 

first thing the air fuel gauge is not accurate and then get a wide band O2 sensor and then the injectors, the LS injectors will do but they will cut out when at higher boost, the pulse width modulated signal from the ECU is somewhat interupted there lacking the fuel that the turbo needs.
YOU NEED MORE FUEL

Re:when i hit boost
 

Its not a question of how "new" the A/F guage is... Mine was brand new too...

Its just not accurate..

Re:when i hit boost
 

the widband o2 sensors are like 300 bucks

Re:when i hit boost
 

I know.... Sucks, but its the only way.... Dyno shops have a wideband that goes up your tail pipe... A place in Orlando by me charges $75 for an hours with the Dyno and using there wideband.

Or you could spend $300...

Sucks I know, but just b/c widebands are expensive doesn't mean your A/F gauge is right ( mine is WAY oFF ).

Re:when i hit boost
 

their is a shop near me that charges 100 for a hour of dyno tunning. i just want to get the car out of the rich zone. I was looking at the s-afc controllers the other night and how do they work. or actually the functions fo they wide the injector pulses

Re:when i hit boost
 

nnnnarrghhhhhkkk!!

a/f gauges are a waste of time unless you have the right o2 sensor for it.

i didn't even bother getting one. the only gauge i might get to tell my mixture would be an EGT gauge, but i don't know where i'd put it.. ohwell.