GTR-Mark

Hi All

I know there are various threads on here about potential Lambda issues. However I want to explain mine to see if anyone has had similar and managed to sorted it out.

W-reg Impreza 2000 Turbo. Standard Car, with a Re-circ valve and panel filter. No major mods.

Two days ago it started to hesitate just before it comes onto boost. I noticed it mostly while cruising at 60-70 in 5th and then going to pull away gently.
It holds back and then goes as if nothing is wrong. If I pull hard through the gears all is ok. I have to get the engine under load at low revs for it to hesitate. It is a true heart in mouth feeling when it loses power and doesn't accelerate.

Anyway, I have done the static mode code test and got an immobiliser error. Code 53. I then had a garage put a proper code reader on it and they also only found the same logged historical error. Not interested in this, but it confirmed the counting the Engine Light flashes tests that you can do with these impreza's does work.

I then tried the Dynamic mode test (2 green connectors), as found on here, and noted the flashes and got code 32. O2 Sensor.

Therefore an intermittent fault from a Lambda sensor would make sense. But how can I tell which one is playing up? Are there any other checks I could do.

Any advise greatly welcomed. Obviously I am trying to avoid replacing each Lambda at £100 a pop .

wrc

Im not 100% sure of your W ref bud, but my 97 jdm wrx only has one? I would have thought yours is the same. It may have a rear lambda cut that does very little engine management wise, it doesnt determine fueling like the first.

I had the same symptoms as you did, i replaced the lambda as thats a main symptom of it - It made hardly any difference.

I reset the ecu the next day, car drove totally new again lol.

So i have a spare used lambda here if you want to try it one day, im down the road in Chi.

GTR-Mark

Top Man.

I wouldn't mind taking you up on that offer.

Must admit I only assumed two lambda sensors from looking up various stuff online. I've not yet had the chance to have a proper poke around.

wrc

Pop over and i'll take a look for you if you want bud. Would definatly recommend an ecu reset first. Disconnect the battery and leave it for over an hour is enough, dont bother with all the masses of ways to reset it that are on here.

GTR-Mark

Thanks very much!

Could you drop me a PM with your details and we'll arrange something. I was going to change the plugs Saturday anyway as I have no record of when they were last done. I'll also disconnect the battery at the same time. If that doesn't help then I'll try your Lambda.

The Rig

iTrader: (13)

Doesnt the lambda only affect like below 3k revs, closed loop etc, once above 3k lambda isnt as important, or am i totally off track ?

Gambit

iTrader: (6)

I used to get that 32 in my my99 classic at certain times in 5th gear also, it was generally under load going up a hill say at 3-4k rpm i put it down to lambda overheat as engine was under heavy load, it went off about a mile down the road.

I had psi3 data monitor so could see there & then what the code was

GTR-Mark

I believe you are right. That is why the problem is intermittent and only happens at certain low revs just as I'm about to accelerate. Once it's wound up it pulls and drives fine.

It is definitely a new fault.
There is a further development. I had to refuel last night and since putting in a fresh tank I have not noticed the hesitation anywhere near what I had last week.
I'm trying WRC's advise and doing a ECU reset this weekend. I'll also change the plugs while I'm at.
Regarding fuel I alternate between 95RON and 97RON depending on the use. I guess its possible the ECU is a little confused or maybe I had a dodgy tank of fuel....??

Gambit

iTrader: (6)

try not to run it on 95RON & 97RON. stick to one rather than continually switching. if you switch it takes the ECU a "while" like a load of miles before it readjusts to the new fuel RON.

a reset will force back to base settings and speed up the adjustment process

GTR-Mark

Sorted!

Guess I should of started with the basic's.

New set of plugs and leads, courtesy of eurocar parts. Less than £40 later, no more strange/intermittent hesitation. Touch Wood.

Now for my first track day

Cheers everyone.