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2003 wrx serious sputtering and bogging need help

9K views 25 replies 9 participants last post by  doc2024t6 
#1 ·
hey guys
im new to this forum and im having serious problems with my 2003 wrx bugeye.
first bogging and sputtering at high load and boost.changed fuel pump and still the same(used pump).
changed coils plugs O2 sensor still same problem
cleaned injectors and changed the seals and still the same.
also checked for leaks nothing at all
and the boost gauge is normal and stable
now its bogging and sputtering from 2000-4000rpm.
another thing, it doesnt sputter and bogg for the first like 15-20seconds on start up even if its cold or hot.whenever i turn it off then on it will act normal and smooth for the first 15-20 seconds.
any thoughts?
 
#2 ·
Some more details on the car's history and mods/lack of mods please.
 
#3 ·
car mods are:
sti pinks
sti tmic
vf30 turbo
perrin air intake
4" downpipe from turbo xs
also turbo xs uppipe
it has ej20 with ported and polished heads
wiseco pistons
manley conecting rods
acl bearings
....
it has been like this for three years with no troubles and as for the forged block its done like only 10k miles.
 
#6 ·
Check crank and cam sensors for build up. Personally, I'd replace them, but you may be able to fix the issue by cleaning them.
 
#12 ·
I know you said you changed your plugs, but did you gap them properly? Is your fuel filter clogged? Is your fuel pump dead? Have you gone over all the vacuum connections? Maybe one of your coil packs is dead? I'm just throwing ideas at you here. It's all stuff I'd definitely go over. Double check the work you did, sometimes I forget to do things.
 
#13 ·
double checked everything man
gapped the plugs
all vaccum connections checked
filter changed
the only thing is the pump i changed it with a used one and im thinking maybe its from the pump maybe its dead too.
so i ordered a new one waiting to get it in the comming days.
but my question is why will it run normally for the first 20 secs after start up
then it will start sputtering again
i think like its 80% from the pump.on start up it pressures good and then off?
i dont know what to do lol
 
#15 ·
guys problem has changed now
now the bogging is a bit less now and something strange now is happening
when i drive with a 10% throttle the car pulls great and seems fine but when i apply full throttle the car hesitates and the strangest thing is that at 6000-6500 rpm the car cuts off.as if u just turned off ignition
any thoughts guys?
 
#16 ·
When the engine is cold, the ecu keeps you in open loop fueling (read maf and adjust fuel based on a preconceived table)- after warm up, you'll switch to closed loop fueling and adjust the amount of fuel based on both the maf and the oxygen sensor (high load will also put you into open loop fueling). Since you've considered both the possibility for intake tract leaks and for a bad a/f sensor, have you considered cleaning the maf sensor?
 
#17 ·
cleaned my MAF sensor i even tried my friend's maf sensor but the problem is the same.
today i even checked all grounds and cleaned them
again guys im thinking.why when i switch off the car and then start it it will be fine for like 15 seconds.cold or hot it will act the same.its not drivable anymore.
thanks for ur help guys
 
#18 · (Edited)
OK, so let's recap.

-You've changed/checked plugs and gapped properly

-You have replaced coils and checked the wiring to them

-You have replaced fuel pump, injectors, and fuel filter

-You have replaced cam and crank sensors

-You have cleaned and tried another maf sensor
 
#20 ·
problem solved at last guys
my new walbro pump is here installed it and the car runs perfect
but there's something strange that i noticed.i test drove the car and came back home i touched the pump plug(connector) and it seemed to be very hot.is that normal?
how hot should it be?
the car runs perfect but i just noticed that the plug is very hot. is that normal?if not what could that problem be.thanks guys for ur help
 
#22 ·
guys car ran great for a week after installed my new walbro
but today while i was driving it cut off.i was driving in traffic not boosting or driving fast.i started it and it ran directly.
then after like 10 minutes also i was driving slowly and it happened again.i tried starting the engine for like 5 times and i went home.i drove for like 30 minutes and sometimes with full throttle and didnt have any trouble.what would that be guys?
i appreciate any thoughts
thanks
 
#23 ·
Can you inspect the plug at the fuel pump connection? See if there is corrosion or even a short? I would clean the contacts regard less.

Check the pins with a multimeter to make sure you are getting the proper supply voltage and a good ground. Move the connector around, bend and flex the cable while reading voltage to make sure there is a solid connection.

Also, did you check your fuel filter and fuel pressure regulator? This sounds like a fueling issue.
 
#25 ·
i checked everything and just installed new fuel regulator and filter
today i noticed that when i start the car after like 5minutes if u touch the plug its hot even the wires are hot.also noticed for the first time that the fuel line coming out from the pump directly is very hot too.the fuel pushed to the engine is hot inside the hose.i dont know if its normal or not.is there a chance that the walbro pump is bad?
any thoughts guys?
the car runs perfect but it just shuts down instantly sometimes while driving.
thanks for ur help guys
 
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