right now i have this setup for my custom T25 on my civic

255lph high press Walbro intank
Stock injectors
Vortech 12:1 fmu
6psi
NGK BKR6E-11 gap@.030

my problem is, ever since i installed my fuel pump.....if i hold boost @ 1-2psi the car begins to studder, but if i hold boost from 3-6psi everything is fine. i also noticed that the a/f gauge bounces back and forth in the rich section when i hold boost aroound 1-2psi. i'm also pressing the throttle like 1/4 way.

i don't know what's going on with this. everyone i know has this setup and it works fine for them. when i'm in WOT the a/f guage reads all the way rich. the problem i'm worried about is why does it studder a bit when i'm only holding the boost @ 1-2psi? someone please help me out before i start pulling my hair out. thanks

-jeff

 

sup jeff... it's me marc (memphblak from aim). my guess is that it could be running very rich right in that area if ur at part throttle. not sure just my guess since it's an fmu.

 

Change your plugs one step colder (7 series) keep the gap @ 0.30.

1/4 throttle is closed loop operation and your FMU is just starting to close and may be pulsing the fuel pressure too much causing a rich condition.

What are you using for ignition retard? You may have too much retard.

Tuning an FMU setup for part throttle conditions is very hard to do. you have to balance the response of the pump, FMU, and the closed loop cycling of the ECU.

My suggestion, if you run out of ideas, is try a MSD 6al to improve the fuel ignition.

BTW-What is your idle fuel pressure? How about off-boost drivability?

Tell us more.

Randy

 

 

can anyone else give me some advice????

 

I think RGAZ hit it on the head. If you're only giving it 1/4 throttle, the ECU is probably still in closed-loop where it is trying to maintain an emissions friendly a/f ratio.

Sonny