brunny42

hi i have UK 2002 wrx sadly not sti, 23000 miles on the clock, full service history, new fuel filter, k n pannel filter, new ngk plugs, 3" cat back system, bailey atmo dump valve, i only use optimax fuel or super unleaded if optimax not be found, the slight hesitation has always been there before anything changed so i know its nothing to do with any of those bits,

the car seems to hold back slightly mainly on light to moderate acceleration, you can tend to feel this more in the higher gears 3 4 5th, once on full throttle or over 4000 rpm you dont tend to feel it, but occasionally you do,also at 140 150 mph it just aint all there, when hesitation is there the tone of everything just dont seem quite right as though not getting correct firing, as tho lacking in fuel slightly, when i changed the plugs they were pink all of them, now usually on most cars they black brown, having owned early 95 wrx wagon, driving and maintaing my friends car my00 2000 awd, other mates 94 wrx sti, all of the other early non EOBD imprezas drive lovely without this hesitation, i have not driven any other EOBD models, i was wondering do i have or not have a fault, does any one else experience this 0n 02 wrx i have no check engine light coming on also i have had my scan tool on to confirm no codes, the MAF has been replaced aswell this made no difference, just add a little note i have had an oscilloscope on the o2 sensor that is positioned in the exhaust manifold where the link crossover pipes join,engine speed at 2k the pattern that usually you should get from good o2 sensor where the signal goes up then down up down etc i did not get this, it just tended to hang around in one place for several seconds then go some where else for rather along time, whilst accelerating or decelerating the signal did rise and fall but not as much as i usually would expect( i specialise on italian cars now owning japaneese, i little under educated on japs) it sounds as though o2 sensor faulty, again to add if i disconnected sensor and put probes direct to o2 sensor and repeated this test the oscilloscope pattern was perfect, whent a little further tested voltage going to o2 sensor this was 4.5 volts, is this correct i on italians recall 0.45 v, can any one help, thanks in advance

Midlife......

iTrader: (2)

Brunny

I run a modded MY02 WRX..

In the dim and distant past I ran it as a de-cat / ITG panel filter(with and without a ECU tweak....TeK 2).

It was always a bit "flakey" and hesitant on part throttle, most noticable while waiting to overtake traffic. Bob's re-map sorted this completely and wondered if there was something about the OEM ECU ?

Maybe some mappers could offer help ?

Errr.... at 140 -150 MPH my scooby "aint all there" either

Midlife.....

brunny42

thanks for the reply i have ordered new o2 sensor as only120 +vat plus got warranty extended so wont actually cost me as got own garage so just do claim on it, if that dont fix it think i will admit defeat and book her in some where its just i hate to admit not being able to find a fault as i am pretty much undefeated in diagnostics as that was my role whilst in fiat dealership, so it better fix her, cheers, the comment about 140 150 i mean no disrespect but after owning fiat coupe 20 vt aswell which went off the clock at 160 @ 6200 rpm with at least another 800 rpm left before redline, i find the rex a little slow top end but great round the corners, unlike the fiat which got me cheeks nipping so she had to go even though i specialise on coops the scooby rules

Midlife......

iTrader: (2)

Teeside.......... the home of many a modded Scooby including the highest BHP ScoobyUK (Harvey). Have you joined TTS yet ??

AS Performance is in your neck of the woods as well.

do a google on Tyne Tees Scoobies and see who pops up

brunny42

yes went to my first tts meating on the tuesday

Midlife......

iTrader: (2)

Just wondered if you met Martin there ?? Perhaps one of the most sorted Bugeye daily drives around. 370 odd BHP.............. and still a nice guy

Shaun

brunny42

yes had a long chat with martin turns out i live very close to him about 8 mile away so i know not to race him now. was impressed with his car to say the least.