Impreza 06 throttle issue

leevvi · Post by **leevvi** » Thu Oct 20, 2011 1:35 am

Hi, seems like a nice forum folks. I have a newby question im afraid.

My Impreza 06, 2.0 Lt, non turbo, 5spd-manl, 160,000km, seems to have a throttle issue when accelerating [medium to heavily], it seems fine upto about 2500rpm [about 1/3 acc pedal], but if the pedal is depessed more [overtaking etc], it seems to struggle severally, not really a misfire type of thing, more a fuel/air starvation issue [by my reckoning], it feels like when ans older style vacuum dual throat carby opens the second throat [theres a silght delay while the fuel/air rebalances], but on my impreza, it keeps going from 2500-4500 rpm, but suddenly at about 4500, it seems to return back to normal, giving full power.

New air/oil/oil filter, no engine warning light [except when i discon'd the air flow sensor, light returned to off after 3 engine run cycles as normal]. engine seems fine in normal suburban driving, only apparent when "giving it a bit", and no, i dont flog the guts out of it.

I havent changed the plugs since i brought it at 150,000, but i took the left side plug lead out today, and noticed a small amount of oil at the top of the plug socket [inside what i call the tappet cover, ...new to subi's, not mechanics, the boxer design is brilliant, im learning], no oil found on RHside though, im smelling a rat, yeah? blown seal, oilway, gasket?

I know its near impossible to diagnose, vehicle unseen, but im just asking opinions/ideas? thanks

certified impreza nutter.

Gannon · Post by **Gannon** » Thu Oct 20, 2011 5:24 am

Welcome to AUSubaru!

First off, the oil at the top of the spark plug chamber is just because the oil seals get hard and leak a little, they are replaceable and arent that dear from Subaru dealerships. PM "FROG" on this forum, he works at a dealership.

But that wont cause your issues.

The culprit could be a dirty air flow meter. Go to a parts store and buy a can of "electrical contact cleaner", but make sure its the stuff that does not leave a residue. Remove your air flow meter and gently spray the sensor wires inside it (you will have to try to spray through the mesh)
This should fix it.

leevvi · Post by **leevvi** » Thu Oct 20, 2011 5:48 am

thanks mate, funny you should mention the AFM, i 1st noticed it after i changed the air filter [the AFM resides on the front side of the air filter box, yes?], maybe i dislodged a chunk of something in the AFM, i'll check it out.

Also, im considering an OBDII to usb cable, any recomendations, they go on ebay around $25, supposedly work with several freeware OBD programs, be interesting to see what the ECU has to say

leevvi · Post by **leevvi** » Thu Oct 20, 2011 10:24 am

just another qwik qwezzy, its an EJ20 engine, are they fuel injected [it listed as normally aspirated]

FROG · Post by **FROG** » Thu Oct 20, 2011 10:33 am

Yeah its fuel injected
pm me your vin if it proves to be gaskets and I will price them for you
cheers Andy

leevvi · Post by **leevvi** » Thu Oct 20, 2011 10:43 am

thanks mate, not sure im ready for that just yet [valve cover removal], im still alittle cautious with the subi LOL, dont have a good shed at present anyways

mud_king91 · Post by **mud_king91** » Thu Oct 20, 2011 11:27 am

buy some air flow meter cleaner clean the afm... if that doesnt work replace the gasket... gannon will hate me for saying this but i had a family friend who had similar issues with her 99 mazda 626... after cleaning the oil out of the plug holes, plugs and leads and replacing the rocker cover it came good so might not be the issue but ideally it needs to be replaced anyway

taza · Post by **taza** » Thu Oct 20, 2011 11:50 am

A OBDII scanner won't work with the 2.0L EJ20 N/A in your Impreza. I have the same engine and its not OBD II, well the ECU.
It has the connectors under the dash to determine CEL flashes to work out the codes. Thats what OBD I has.

Maybe the ECU is OBD II with the newer EJ20's. IM not completely sure.

Taza

d_generate · Post by **d_generate** » Thu Oct 20, 2011 2:21 pm

06 will have the OBD 11, yours is ancient technology Taza.....I think they were standard from 99>

taza · Post by **taza** » Thu Oct 20, 2011 2:50 pm

d_generate wrote:06 will have the OBD 11, yours is ancient technology Taza.....I think they were standard from 99>

Really because mines a late 2001 (MY02)?? It has the connectors under the dash for making the CEL blink to count the flashes to determine the code. Had to use it a few times

Gremlins · Post by **Gremlins** » Thu Oct 20, 2011 2:54 pm

Is your 06 Impreza the 2.0R model with the twin cam motor? I seem to remember these had reports of "flat spots" in acceleration when they were first released. It's a while back but I remember some talk that the issue was corrected by a firmware update on the ECU. Also, if it is the twin cam you should be using premium unleaded of 95 RON or greater as this is what is specified for this motor. I seem to also remember reports of performance issues being experienced if 91 RON was used and this was one of the issues the updated ECU firmware was supposed to address.

Post by **Alex** » Thu Oct 20, 2011 3:03 pm

taza wrote:Really because mines a late 2001 (MY02)?? It has the connectors under the dash for making the CEL blink to count the flashes to determine the code. Had to use it a few times

My 2001 my02 2.0l liberty runs obd II.

Sent from my HTC Desire using Tapatalk

leevvi · Post by **leevvi** » Fri Oct 21, 2011 7:30 pm

thanks folks, just waiting on the OBD cable. Im pretty sure that all cars after 2001 [at least ones with an ECU] are OBDII compliant. There seems to be a standard set of codes and some manufacturers add their own special codes.

The seals dont seem to be urgent, so im on hold at present, definately in the near future though.

One last qwezzy, ....are the alternator bearings [or water pump bearing], known for giving a rattle [vibration], when backing off the throttle and changing gears? I had an older car that did it also, stopped when i replaced the alti.

Gannon · Post by **Gannon** » Sat Oct 22, 2011 6:46 pm

My 01 Outback 2.5 isnt OBDII compliant, even though it has an OBDII plug under the dash.

I have found that if you have an air intake sensor on the front of the air filter box, and or have 2 oxygen sensors, you have OBDII. If there is no sensor on the air box and you only have one oxygen sensor, you have OBD1 and 2 green and 2 black plugs under the dash

leevvi · Post by **leevvi** » Sat Oct 22, 2011 8:04 pm

I just found an interesting fact about the Aust Design Rules, regarding OBD II in Australia.

ADR rules did not require an active OBD2 system in Australia before Jan 1st 2006, MOST vehicle manufacturers did not switch it ON.

Europe adopted it in 2001, USA in 1996. Japan has its own JOBD standard. Its a bit hard to get info on Subi's so far.

i'll let ya know if mines compliant

Gannon · Post by **Gannon** » Sat Oct 22, 2011 8:55 pm

Just had a flick through the 2006 Impreza FSM, it appears that your car is OBDII compliant.