Ok Guys and Gals,

I need some major help. Here is the story...
I have a modified 2002 WRX and I starting noticing a problem one day when hitting about 4000rpm. The car would all of a sudden loose power and act like it didn't want to move. At about 6000rpm it would clear up but still considerable power lose. Something to note: The last set of mods done before this problem started was the addition of a Infinity Basslink Powered Subwoofer and a set of JDM non-HID headlights. All electrical items.

I took the car to the dealership and they told me it was most likely the fuel filter. Had that replaced but still broke. About a week later I got a CEL and it was the O2 sensor. I took it to a reputable performance shop and 2 weeks later it is still there. I think they are working hard on this problem but they can't seem to find the issue. They have replaced the O2 sensor, fuel regulator, spark plugs, upipe (thinking the catalytic convertor broke off), cleaned but not replaced the MAF sensor and now thinking about replacing the ECU. They have also disconnected my S-AFC to determine if that is what was causing the problem. Since they have worked on it has thrown several CELs including:

P0301 Cylinder 1 misfire detected
P0302 Cylinder 2 misfire detected
P0303 Cylinder 3 misfire detected
P0304 Cylinder 4 misfire detected
P0500 Vehicle speed sensor malfunction
and a fast blinking CEL which I'm not too sure what that means.

The car still has the original problem and I'm not sure what else to do. The car is modified and includes the following relevant items.

Blitz FATT DC Turbo Timer
Blitz SBC-ID Boost Controller
Blitz ID-3 Power Meter
Blitz AC series 60mm black (boost, EGT and oil pressure)
A'PEX S-AFC II Fuel Computer
Greddy v-spec Front Mount Intercooler
Greddy BOV
Greddy Airinx Air Filter
Greddy Oil Catch Can
Iridium Spark Plugs
Perrin Pulley Kit
Perrin Downpipe without cat
Tanabe Hyper Medallion cat-back exhaust
Hot Earth Grounding Kit
Walbro Fuel Pump
JDM STi Projector headlights

I would appreciate any help you can give.
Thanks in advance.

 

Why do you need a fuel computer? That may be the problem. If you do not know how to use it properly.

 

I had the fuel computer tuned using a four wheel dyno and it ran great for about 7 months. I added the fuel computer since I plan on doing more mods like bigger turbo.

 

Pull the grounding kit, pull the sub, pull all the drain on the battery except what came with the car. Check your hoses to and from the turbo.. for the wastegate.. check to see if there are any melted wires going from the harness to the maf, check to see if the sensor in the up-pipe is still in tact.

Pull the plugs again, its really not that hard. And tell us what they look like.. if you can take a pic of them.. do so.

Check the air filter lately?

Would you happen to know what your IDCs are?

Stock injectors?

I don't mean to give denso a bad rep. But from the ~10 wrxs I've changed plugs on in the past month or so for stage 4+ setups. Densos have given me a shi*oad of issues. Esp with misfiring. But most cars, especially ones with UTECs (you apparently don't have one, but nonetheless) they won't record any knock but the CEl will flash and apparently its a misfire; thats all we have been able to sum up out of ~6 hours of work two weeks ago. Heh.

Good luck. Id say pull everything thats not necessary to have the car work.. and the items with the drain on the battery. If you are still getting crap.. I'd say pull the plugs and take a look see at em.

-G

P.S. I've also run into issues with pulley kits on WRXs.. sure some people have absolutely no problems with them.. But I've run into two instances where it effects speed.. incurring hesitation, et al.

 

Thanks WRXWagon for the in depth reply. I actually purchased a set of coil packs
that will be replaced tomorrow. A lot of people think that this is the cause of my problem.
I have checked for melted wires and the hoses to and from the turbo and wastegate, all look good. The plugs have been replaced but I will get them checked again.

I have also heard of pully kits and the denso plugs causing problems. If the coil packs don't fix the issue I will continue with more of your suggestions. By the way, I do have stock injectors and what are IDC?

Thanks again for the reply.

 

If you don't know of IDC (IDCs, IDC's.. many people write it differently).

But anywho.. if you don't know what it is.. then get the F rid of your fuel computer right now..

Sorry.. now onward.. have you checked out anything more?

-G

 

I don't know anything yet but hopefully I'll know more later today.
Are you talking about injector duty cycle when you say IDC? If so, I don't know the cycles but they are the stock injectors. I had my fuel computer
tuned by a professional on a four wheel dyno so I'm sure it was tuned correctly.

 

Didja , per chance, mess with the fuel computer at all.. knock it, kick it, bite it, lick it, et al?

If not.. pull the darn plugs!

-G

 

I see you have a Perrin Pully set- that in itself might be the P30X CEL problem.

Both lightened flywheels and underdrive pullies are known to disrupt the engine balance just enough to set of false misfire codes.

 

No, I don't recall ever kicking, hitting, licking , etc the fuel computer. I will get those plugs checked again. They replaced the ecu and coil packs today and it had no effect on the car.

 

Well, it looks like the car is finally fixed. After removing the S-AFC the ECU was reflashed using the Cobb Accessport. Also, a bad ground wire coming from the coil packs was found.

Thanks for everyones help.