badman1972

Wonder if anyone could offer any help on what might be the cause of my car just starting to hesitate under any sort of acceleration at 3k revs, it drives fine upto this point and feels like it is going to start pulling hard on boost then starts stalling and holding back quite badly and has seemed to get worse last few days.

Car is '07 plate Hawkeye STi Type UK 18,000 miles was re-mapped at 10k miles by JGM after fitment of Cat-back exhaust and Green panel filter. Car has run like a dream since then until Saturday. FSH and had 3rd year service done July this year.
Always run on super unleaded which is what it was mapped on.

Any ideas anyone?

fpan

iTrader: (11)

Can you read the ECU and are there any errors?
First things to check would be MAF and O2 sensors.

Dougmy06wrx

iTrader: (4)

You could try cleaning out the boost solenoid. Not sure if that would be the problem but worth checking an free to do.

HTH

Doug

x-helen-x

I had this with my 2007 hawkeye too!! Like it juddered/hesitated when putting foot on accelerator... took it back to Subaru who flashed the ECU (whats that) and been fine from then.

H x

BrownPantsRacing

iTrader: (6)

Have you got an after market dump valve on the car? They can sometimes stick open. Have had same on my Hawk. Changed it now for a decent HKS ssqv.

L.J.F

iTrader: (31)

I would go with the MAF and o2 sensor.

whiteknuckleride

could be knock sensor picking something up and retarding engine?

i had this problem from No4 piston ring

hope its not quite as dramatic as that but i had the exact same symptoms and it ended up with a complete rebuild

a compression test would prove if all is well

good luck sir

badman1972

Its been into local Subaru dealers today, just had call to say can't find fault, tried changing MAF, still same, no faults on ECU but cannot read the map due to re-map and Subaru themselves won't help because of the same reason.

The car doesn't have a dump valve, it is standard apart from the re-map, Cat-back exhaust and panel filter.

Thanks for the replies so far. Does anyone know a specialist close to Middlesbrough North East?

jura11

iTrader: (7)

Hi matey try contact your mapper about this?And you will see what you say,this is probably best bet for you.

TonyBurns

iTrader: (3)

I would have a read through this thread....
https://www.scoobynet.com/scoobynet-...-failures.html

Tony

badman1972

Sorry Tony, why was that mate? I have seen that thread before but was relating to 08-on hatchbacks wasn't it? My car was out of its 3 year warranty period anyway in July this year.

badman1972

Picked it up tonight from dealer, who didn't charge anything for the work/time, this is what they wrote on the report:-

"Check on SSM no codes stored as no warning lights on/Road test and experienced dip in power at 3500 and 4500 RPM.
Check component activity all ok except air flow meter dips at 3500 rpm/swap air flow meter and road test.
Seems slightly improved but still dips at 3500 RPM"

He commented on collection that it runs really well until the hesitation, then picks up again inbetween (note - although nothing like it used to a week ago) then another tailing off/hestitation. He thought the air flow meter might be a red-herring as they didn't know what caused the 'dip' and a replacement didn't cure it.

I noticed on the way home that it actually pulls fine on some occasions on half throttle and didn't hesitate, while other times it does.

TonyBurns

iTrader: (3)

It covers all the 2.5's from the hawk onwards, they normally suffer similar symptoms before failure hesitation was one of those.
Have you checked for oil useage?

Tony

Jolly Green Monster

iTrader: (4)

when were plugs last changed?

badman1972

Yes mate, checked it as soon as I stopped after first noticing problem, it barely changes on the dipstick, it has probably dropped a few mm's over last 6k miles.

badman1972

As far as I know they haven't been Simon, asked dealers today who said they don't get done until 40k miles and it only has 18k on. I asked if they checked gaps and he said no.

Jolly Green Monster

iTrader: (4)

I am in sheffield tomorrow.. pm me current contact details and I will see if I can get over to check the car tomorrow at some point

Simon

53

iTrader: (41)

If you're running more boost/remap it's a good idea to start with fresh colder plugs .

I was going to suggest overboost as this is very common in 2.5's but you say no fault codes ?

Jolly Green Monster

iTrader: (4)

I wondered over boost in colder weather too but think it would have reared its head before now and no code.

plug hessitation would be an easy id, and if we are able to hook up tomorrow an easy check

Simon

53

iTrader: (41)

My Spec D'shed does it, not driven it for two years in the cold, and I thought it was fixed hey ho

fpan

iTrader: (11)

It's about time you change the oil if it has done 6k miles.

badman1972

Would be great if we could mate (fingers crossed) the car actually ran brilliant as it has since being mapped during all the coldest weather, then started with this on Saturday which was probably warmest day here for a while at 6 deg C.

Jeff

badman1972

Was changed at last service July 2010 around 12k on clock not due till 10k from then or 12 month is it??

Jolly Green Monster

iTrader: (4)

strange if it were boosting too high it would have done it when colder etc

unless there is a small leak or something

see you tomorrow

badman1972

Thanks Simon, very much appreciated mate

Mrfastbaz

i can support tony my sti type uk with 12200 miles on had bottom engine failure in july and before it started making rattle rattle noises it was hesitant, had a slightly rough tickover and used some oil this on a car that was a 57 plate pre hatch car had a replacement short engine and have now covered 3000 miles since end of september when i had the car back so far so good... could be the beginning of engine failure hope not for your sake...

14N-FR

iTrader: (3)

My car was hesitating right before the engine let go. Two piston ringlands were cracked and one of them scored my cylinder bore which has resulted in a new block pair having to be bought and a full rebuild from the ground up.

Jolly Green Monster

iTrader: (4)

Just checked op car.

No ringland damage noticable or heard in detcans, no over boost and as usual the issue had gone, my thinking plugs carboned up a little with mileage on them and the recent weather meaning no blasts to clean them and the cruise down to meet me had cleaned them up a little.

Ecu had pulled a little timing so I removed a tiny bit as a precaution - plugs or perhaps a bad batch of fuel, however now driving 100% but recommend a new set of plugs.

Simon

badman1972

All I can say is Simon, you are a legend mate

Can't thank you enough for taking time out on a freezing cold night to come and meet me and check the car over, I also can't believe how great it feels having the car running right again compared to how bad it was since the weekend.

Thanks also to everyone for their input

Jeff

53

iTrader: (41)

Top man

Car happy = Jeff happy