2009 WRX - This car has been only a nightmare to me.

[c00lit]

You probably already saw my car for sell in the For sell section.

I bought it cheap, put in now 4700$ of repairs on it.
Turbo, timing belt, firewall welds, new brakes on all wheels steering rack and quite a few more things...

Car runs pretty much alright with the MAF unplugged, but I have cruise flashing, CEL on and Traction Control off.

Got an "OEM" "Genuine" MAF from Ebay for 30 Euro... no surprise, not OEM or Genuine, not even working. Car is just dead with it plugged in.

So I bought from a reliable source, a nice, new, OEM MAF sensor.
No more warning lights, all is apparently flawless...

But now the car stalls out when clutching down or putting in neutral while going onto a stop sign or a red light. When RPM goes down, it just has trouble staying right at the idle.
Sometimes it won't stall, sometimes it will struggle and get back to normal, sometimes it just stalls out.

If it's on idle, it will stay perfect. only when RPM is going down from driving.

I want to like the car, but this one has been a painful experience to me.

Words cannot describe and an evil overlord could not fathom how much I despise this f****** garbage car.

Dropping the price down to 7500$ if anyone is interested... (That's a 1200$ loss on my end)

But if anyone has any experience or ideas on what is wrong with the car, I am open to suggestions.

For one, I will try to find an OEM airbox.

[huck_this]

Did you remove positive terminal on battery when playing around with MAF sensor? The reason is the ECU resets itself and relearns the new parameters when you change sensors etc. Sound like your ECU is confused.

Re-connect the battery after 15 mins or so. Start the car from cold (morning after), let warn up to operating temperature. Turn-off. Re-start and go for a drive.

Also, at cold start-up, the ECU reads from the MAF until the O2 sensor reaches to operating temp. If it runs like shit cold, MAF is culprit. Open loop = MAF sensor, Closed loop = O2 sensors.

I remember my Forester running flaky. Irratic idle, voltage was off the charts for O2 sensor. Should read 5V, was getting 0-12V. Check O2 sensor too.

[c00lit]

Hey, thanks for your reply.

No, I just removed the old MAF (Which was always unplugged as the car would always shut down with it plugged in)

I added the new MAF and plugged it right away.
Before turning on the engine, I cleared the codes with a blue tooth ODB2 adaptor / Torque lite.

Started the car, no lights no nothing.
Car runs perfectly from a cold start. As it warms up, it stalls out faster.

At this point I am convinced my old MAF is also fine, specially since I cleaned it with the MAF cleaning spray...

[huck_this]

Do as I stated above. Cold engine MAF. Hot engine O2 sensor. Reset the ECU. If it has same symptoms, your 02 is toast.

[Kolia]

Also, make sure ALL vacuum hoses are plugged where they are supposed to go and none is blocked by debris/spider nests...

[c00lit]

You guys will have to excuse my newbiness


So,

Unplug Positive on battery.
Wait... minimum 15... I don't mind waiting over an hour watching tv.

Go back to the car, reconnect battery.
Start the car, curse for losing my radio station programing while the car warms up to operating temps. (Not driving ? )

Turn off the car
turn back on and go drive around.


When cold it runs perfect actually. Only after driving a bit does the stalling begins.

I would have a feeling it's the O2 sensor, however,
If the MAF is unplugged, the car runs almost perfectly and never ever stalls.

[huck_this]

That is because ECU is using a base fuel map with throttle position input. Timing is retarded so you don't get ping etc. No reading from MAF and flaky 02 sensor. ECU goes into a limp home mode because MAF isn't plugged in and ECU suspects bad parameters from 02 sensor. I've seen 0V to 12V fluctuations on an 02 sensor when it should be 5V. No CEL came on until later.


Your best bet is to disconnect the battery the night before. Reconnect next day and start it cold without touching gas pedal. Start it, let it idle to op temp and turn off. Then re-start car and go for a drive. The reason from cold, ecu will reset from base up to op temp.

[c00lit]

I have disconnected the battery overnight.
Reconnected the battery this morning.
Started the car, let it warm up for 20 minutes on idle.
Turned off
Restarted and went for a drive.

Stalling problem still happens. No CEL light... went to work like this, I can manage to drive it but it's annoying.
Also, if I floor it, I hear an unusual backfire noise I never hear when the MAF is unplugged.

I will order an O2 sensor from Rockauto....

Question, does an O2 Sensor for an EJ257 work the same as one for EJ255 ?
Why would the one from EJ255 cost that much more? Looks like it's about the same.
http://www.rockauto.com/en/catalog/suba ... on,oxygen+(o2" onclick="window.open(this.href);return false;)+sensor,5132

(No matter, I ordered the one for the EJ255...)
BOSCH 15028 Bosch Engineered Oxygen Sensor; Heated; Wires: 4; Length (in): 173
Downstream; Engine Code EJ255

[huck_this]

sounds like a failing 02 sensor. You need the upstream one for air/fuel ratio (before cat-cons). downstream is just a sniffer to throw a cel regarding failing cat-cons (after cat-cons).

[c00lit]

Thanks for the information and shit... I ordered the downstream... didn't realize.
Canceled 1 order and updated the order to the more expensive upstream sensor...
Had no idea... thanks for the info.