reaction360

I'm sure i could've made a search and found this info after reading pages and pages of old posts. but i'm a bit lazy

we just did a homemade turbokit on my buddy's 2000 civic ex and are having a fuel problem. or at least we think we are.

Whats goin on?
now i kno A/F guages arent the mose accurate things to use, but his guage reads normal while driving, idle and initial boost, but once he hits about 4-5psi, his a/f guage does a drop all the way into bottom lean. and it does this pretty consitently, everytime he boosts.

he's running a T3, vortech 12:1 fmu, Airtex inline fuel pump. missing link.

thanks in advance.

b16ahybrid

The only way to really know whats going on is by getting it on a dyno and checking it out. Or get a wide band o2 and meter.....
Btw as you know, the air/fuel ratio gauge hooked up to your stock o2 is worthless. The only accurate thing mines has ever done, was tell me that my o2 sensor no longer works. i tuned my car to a 12.0:1 afr on a dyno, my gauge still reads lean under boost about 50% of the time the other times it reads rich under boost........

JDogg

i would suspect the fuel pump. stock pressure is 40ish, at 50 psi with the 12;1 fmu that would add 60 psi, thats 100 psi. get a guage on the car and get it on a dyno. make sure you have the lines on the fmu hooked up correctly

reaction360

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">i would suspect the fuel pump. stock pressure is 40ish, at 50 psi with the 12;1 fmu that would add 60 psi, thats 100 psi. get a guage on the car and get it on a dyno. make sure you have the lines on the fmu hooked up correctly</TD></TR></TABLE>

well we're running the vortech fmu and we installed the Airtex inline pump which comes with the Drag turbo kits. he has a b&m guage on his fuel filter and we did notice fuel pressure at idle bumped up to 50psi. I'm going to check his plugs again, but do you think he's still leaning out at 5psi? that's all he's running.

thanks for the input guys.

integrx

under heavy acceleration the AF gauge should read rich (the green part).

b16ahybrid

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integrx &raquo;</TD></TR><TR><TD CLASS="quote">under heavy acceleration the AF gauge should read rich (the green part).</TD></TR></TABLE>

it should if it could accuratly read the air/fuel ratio.
The problem with the meters hooked up to your stock o2 is that they are not wide band so the accuracy range is very minimal, the further away from stoich (14.7:1) you get the less accurate they read. They are generally only good for N/A engines. In general a safe afr for a boosted engine is around 12.0:1 +/- a little so the accuracy is not that great...If you want an accurate measurment of your afr you need a wide band o2 sensor

JDogg

all those autometer guages are good for is telling you if its richer than stoich or leaner than stoich. if you see it go lean then it is leaner than 14.7.

b16ahybrid

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">all those autometer guages are good for is telling you if its richer than stoich or leaner than stoich. if you see it go lean then it is leaner than 14.7.</TD></TR></TABLE>

And half the time they cant even do that.