my a/f muixture was fine until recently. I am now getting lean mixtures the whole time in boost, as soon as the BOV goes off it will go rich though. the car hardly pulls after 5psi since it is lacking the fuel. Is this a sign of a bad fmu?
#88826, "RE: vortech FMU gone bad?" In response to Reply # 4 Aug-18-05 04:39 PM by Semperboost
Originally posted by Dan Zeller whats so wrong with my setup? it is basically the same as a star or hahn kit. The vortech fmu should do its job right?
Don't boost past 5psi..
1) You're on stock injectors, you're maxing them out especially if it's not up to par (fuel filter/ clogged injectors) 2) You're not intercooled - hot air is not good period.
Not enough fuel + HOT air = bad things
You can't tune soley on a narrow band, you should invest in an EGT and fuel pressure gauge. Eventually you'll need them.
#88850, "RE: vortech FMU gone bad?" In response to Reply # 6
Originally posted by Dan Zeller any help with the fuel problem?
Checking your fmu would be a good place to start. Just take it apart, it sounds like you could have a hole in the diaphragm or maybe it's gummed up inside. The diameter of the 12:1 disk is almost the same size as the inner diameter of the fmu which makes it easy to bind. Finally you could check your signal line and make sure it's seeing boost.
Since you're running lean, I would try to lay off the boost until your issue is resolved. Once it's resolved 7psi would be a lot safer until you upgrade your fuel system. Hope this helps.
____________________ 04' EVO VIII Tarmac Black 99' GS OZ Ed.- Sold
#88854, "RE: vortech FMU gone bad?" In response to Reply # 7
I checked the fmu, the brass fitting for the boost signal was pressing on the diaphram, I backed it off and put more teflon tape on it. Now I see rich mixtures again under boost.
I installed a 0=100psi fuel pressure gauge on the test port and watched it through the windshield. I have approx 48psi at idle and under boost up to 5lbs it goes past 100psi.
If I change to the turbo eclipse injectors, any idea what disk I need in the fmu?
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