turbo problem i never faced

[NvidiaForTheWin]

hi guys.
i turboed around 15 car in my life but i'm facing a problem i never faced before.
first , it's the first time i do a basic setup. other was professionally made( was my job , afterall ! )
some of you know i'm turboing my winter ebater aka the hyundai accent 1999.

when the boost gauge show 4-6 psi the engine sputter like hell.
this happen around 4.5-5k rpm depending on load.
i have no idea what can cause this on my situation.

here the car and setup.
hyundai accent 1999 1.5l sohc 12v , 302 000km
run like brand new before the turbo

CXRacing T28 turbo w/ 14 psi internal wastegate ( machined to 10 psi )
CXRacing blow off valve
CXRacing silicon couplers & clamps
CXRacing intercooler
OBX 8:1 fmu
GlowShift boost gauge
GlowShift oil pressure gauge
GlowShift wideband gauge

there no leak at all , i checked like 10 time.
i don't think it's related to the fmu because
1* plugged or not = same problem
2* 8:1 seem to be the perfect one for my goal and my stock injector.
3* tried with friends 6:1 and 12:1 = same thing
it may be the timing... but those engine have automatic timing wich is supposed to be good for 12 psi ( 7 professional told me )
the spark plugs are 1 step colder
spark wire are new from 2 month and are ok
ignition coil are ok too
my MAF sensor is temporary fixed between the air filter and the turbo but will be placed between intercooler and bov
i placed it here first because my boss told me to put it here when we did all those turbo setup on maf based engine and we never had trouble.

i can't give you the AFR because i didnt installed wideband yet. i want to fix this first.

any idea what can cause this ?
could my ecu be such a fu***r and wont work properly with my maf at this place ?
at idle it is perfect. the only small trouble is when i rev it and stop , the rpm go under 300 rpm for half a second and come back to normal.

[Bishop]

The wideband is going to be the most important thing when trying to figure out this problem, im willing to bet its going lean there, I really don't like fmu's, bigger injectors and real tuning will always yield better results.

[NvidiaForTheWin]

The wideband is going to be the most important thing when trying to figure out this problem, im willing to bet its going lean there, I really don't like fmu's, bigger injectors and real tuning will always yield better results.

fmu work GREAT for 5-10 psi. its a proven fact.
i must agree that injector + piggyback is the best solution but....
i would need to be the biggest retart ever to pay the tune for a car that i will get rid this summer. don't you think ?
450+tx for the unit , + 150-600$ the tune for a 1 winter car.... yes , need to be very retart
i will keep all the parts for the elantra but the fmu. it will get a smt6 with a good tune.
fmu was the only non-retarded solution in this case.

i tested my fmu in my friend civic ( wich use the same obx 8:1 fmu ) and it work fine so MY fmu isnt the problem.

i installed the wideband gauge. i will try tomorrow ( too cold outdoor at night )
but i'm sure i found the problem.
i'm 90% sure the fmu isnt connected right so it doesnt work at all. i will invert both fuel line tomorrow and try.

my brother seem to have the same problem with his 03 accent GS.
but we could not find how to hook it another way.
in 2003 accent , there no fuel in the return line because the fpr is in-tank
i called 3 tuning chop and no one could tell me how to hook it in this case.

anyway i will fix mine first !

[Bishop]

The wideband is going to be the most important thing when trying to figure out this problem, im willing to bet its going lean there, I really don't like fmu's, bigger injectors and real tuning will always yield better results.

fmu work GREAT for 5-10 psi. its a proven fact.
i must agree that injector + piggyback is the best solution but....
i would need to be the biggest retart ever to pay the tune for a car that i will get rid this summer. don't you think ?
450+tx for the unit , + 150-600$ the tune for a 1 winter car.... yes , need to be very retart
i will keep all the parts for the elantra but the fmu. it will get a smt6 with a good tune.
fmu was the only non-retarded solution in this case.

i tested my fmu in my friend civic ( wich use the same obx 8:1 fmu ) and it work fine so MY fmu isnt the problem.

i installed the wideband gauge. i will try tomorrow ( too cold outdoor at night )
but i'm sure i found the problem.
i'm 90% sure the fmu isnt connected right so it doesnt work at all. i will invert both fuel line tomorrow and try.

my brother seem to have the same problem with his 03 accent GS.
but we could not find how to hook it another way.
in 2003 accent , there no fuel in the return line because the fpr is in-tank
i called 3 tuning chop and no one could tell me how to hook it in this case.

anyway i will fix mine first !

fair enough on the costs, i've not net used fmu's so i cant say for sure of not if the lines are hooked up wrong.

[NvidiaForTheWin]

i replaced fuel filter and it fixed the problem ( engine cutting at high rpm @ 4-6 psi )
but now , the rpm just stay there ( over 4k ) , wideband hit its maximum value ( 20 ) , making no power at all , engine backfire , and oil splash out of the oil cap on valve cover when i release gas , so can't even get over 4 psi now.

WHAT THE F**K IS WRONG HERE !!!!!

i've built many car for poeple and never faced this problem. tho its the first time i do a low budget turbo project and with a FMU.

the FMU itself work properly and better than i expected.

i will upload a video. you will be able to hear the POP sound of oil poping out from the cap right after the bov sound and see what happen.

video should be online tonight or tomorrow.

in the mean time , you got any idea ?

[Bishop]

fuel filter sounds right, 20:1? thats quite a bit off.

I think your getting a ton of blowby.

[NvidiaForTheWin]

fuel filter sounds right, 20:1? thats quite a bit off.

I think your getting a ton of blowby.

thats possible ! it has 302 000km and it never been opened at all.
that would explain why it run as a brand new engine stock but do this when the boost come

but i don't understand... my brother 2003 accent GS have the same setup with same parts ( but aluminium piping , mine is made with exhaust tube )
he have the exact same problem.
his engine is perfect.
200 000km compression is perfect and never got beat like mine.
nothing have been changed internally but have been checked by a professional the same day he bought it.
he said he rarely saw a 200 000km engine in that good condition and he was sure it wasnt its real mileage ( but it is )

same setup , same parts , good condition VS bad condition , 100% same problem. can you explain ?

by the way , here the video

  Code:

https://www.youtube.com/watch?v=mYIizO5TnCw

[Bishop]

if its hitting 20:1 on the wideband your going way way lean any probably getting wicked knock.

[NvidiaForTheWin]

if its hitting 20:1 on the wideband your going way way lean any probably getting wicked knock.

thanks for your help
i already tought about that but WHY !
my fmu is connected to my vacuum manifold with boost gauge and bov. that's correct ?
i don't see any fuel leak.

something i found strange is there no difference if i unplug the fpr vacuum and block it , with or without the fmu , with or without boost ( unplug piping ).
also i checked my spark plugs and they are clean ( ran them about 200 km ).
that mean no oil is comming on the piston.
that would also mean my ring are OK , no ?
i don't think i have vacuum leak , but can this be the problem ?
i know the problem is that it run too lean under boost , but i need to know why to fix it.

[NvidiaForTheWin]

probleme almost fxed. it was a vacuum leak.
the fmu work great
the oil problem isnt fixed tho
and the wideband indicate correct number until the rpm stop getting higher but wway bettter than before.

EDIT :
i just called 2 garage and 3 tuning shop. the two garage and 2 tuning shop has no idea what was going on/how to fix it.
but the last one told me like you , lots of blow-by there.
and there was 2 solution.
1 : oil catch can
2 : modify pcv valce.

do you agree ?

on my end , oil catch can would be easier because i'm a DIY FREAK and i have all i need to make one.
if im better to modify the pcv i'm lost as i have no idea how.