kunchris
10-11-2013, 07:55 AM
hey guys
i am running a V2 STI ej20g in my legacy with aftermarket v5/v6 440cc injectors
a sard FPR set to 3.5bar base pressure, all in parallel fuel delivery,
vf22 turbo,
FMIC,
walbro gss341 fuel pump.
with an ESL ecu tuned at 1.3bar boost.
all this is running on a MAFless/ speed density setup.using a scaled v3/v4 MAP sensor.
(problem also occurs when i go back to using the MAF sensor)
occasionally and annoyingly, i get a small pop or bang while boosting especially on first gear and 2nd gear, this is accompanied by abit of a jerk in torque delivery.
the rest of the gears are fine.
i am running v7, coils and plugs are 6month old PFR6B gapped to 0.7.
while logging i'd pick up abit of knock counts when this happens.
this will happen occasionally after long traffic stops, slow driving or shutdown periods. id floor it and boost will kick in but there will be a small bucking with a pop. then the rest of the gears are smooth with constant torque and power.
sometimes it will boost just fine with no problems.
there is no CEL whatsoever.
i have an AEM wideband which shows a slight lean out during the pop, like a jump from 11.2 AFR to 11.9AFR then back to 11.2 then it stabilizes..
i have interpolated by fuel tables perfectly and my map works well in other cars, including rally cars with my ecu with no anomaly.
which got me thinking could my fuel pump be burping or not holding pressure correctly at high loads/low.?? why is it only on first and second gear??
the rest of the gears pull fine and hard with no problems. i have a slight lean out at the peak of my power-band... which also is not consistent. as most of the time its stable at 11.2 AFR.
i used T-Pieces while doing my parallel conversion. should i use Y-pieces?? could they be causing some constriction thus air bubbles??
i have been having this annoying problem for the better part of the year, but i have tried everything with no avail.
doesn't matter if i have a full tank of fuel or half a tank.
help and suggestions would be appreciated.
i am running a V2 STI ej20g in my legacy with aftermarket v5/v6 440cc injectors
a sard FPR set to 3.5bar base pressure, all in parallel fuel delivery,
vf22 turbo,
FMIC,
walbro gss341 fuel pump.
with an ESL ecu tuned at 1.3bar boost.
all this is running on a MAFless/ speed density setup.using a scaled v3/v4 MAP sensor.
(problem also occurs when i go back to using the MAF sensor)
occasionally and annoyingly, i get a small pop or bang while boosting especially on first gear and 2nd gear, this is accompanied by abit of a jerk in torque delivery.
the rest of the gears are fine.
i am running v7, coils and plugs are 6month old PFR6B gapped to 0.7.
while logging i'd pick up abit of knock counts when this happens.
this will happen occasionally after long traffic stops, slow driving or shutdown periods. id floor it and boost will kick in but there will be a small bucking with a pop. then the rest of the gears are smooth with constant torque and power.
sometimes it will boost just fine with no problems.
there is no CEL whatsoever.
i have an AEM wideband which shows a slight lean out during the pop, like a jump from 11.2 AFR to 11.9AFR then back to 11.2 then it stabilizes..
i have interpolated by fuel tables perfectly and my map works well in other cars, including rally cars with my ecu with no anomaly.
which got me thinking could my fuel pump be burping or not holding pressure correctly at high loads/low.?? why is it only on first and second gear??
the rest of the gears pull fine and hard with no problems. i have a slight lean out at the peak of my power-band... which also is not consistent. as most of the time its stable at 11.2 AFR.
i used T-Pieces while doing my parallel conversion. should i use Y-pieces?? could they be causing some constriction thus air bubbles??
i have been having this annoying problem for the better part of the year, but i have tried everything with no avail.
doesn't matter if i have a full tank of fuel or half a tank.
help and suggestions would be appreciated.