CupraDave

iTrader: (1)

Hi all, was wondering if you could help me?

I have been reading your great site for a while now and found all the info I needed but for some reason never registered.

I have a '98 WRX which has developed a slight hesitation/miss between 2000rpm and 2500rpm before the boost comes in, (and no its not turbo lag, I am not that stupid). But after the boost kicks in the car is drives fine and will drive fine consistantly as long as the revs are kept above 3000rpm

Unfortunately I am away from home at the mo and wont be back until a week on Tuesday so cant get under the bonnet but do you have any suggestions for when I get home?

Thanks and keep the great advice flowing.

Chad!

Try unplugging the lambda sensor and go for a spin. Also lots of threads on here about the same kinda problem if you have a look around.

Chad!

prana

yeah does sound like problem in closed loop running, likely O2.

Sc0oby

check your sparkplugs

Gear Head

iTrader: (2)

Can confirm the lambda problem (situated in the top on the downpipe, near the turbo). Just unplug it and go for a drive. Tried this in my UK99 Turbo and the hesitation when cold, dissappeared completely.

CupraDave

iTrader: (1)

Thanks guys
Checked the plugs and they are fine so will try the lambda thing when I get home.
Strange thing is tho it does it when cold but seems to get worse the hotter the engine is

prana

Hi CD, not strange. It doesnt go into closed loop at start up, only when its warmed up.

fatboy_coach

iTrader: (1)

I know this may be a stupid question, but would a remap solve this? My MY00 suffers from this and I'm trying to get get rid if it (the problem, not the car!).

Ian

prana

Ian, if it is one of the key transducers that has failed, no remap would not fix it. Probably for you, you need to find out what failed. If it's a bad map then a remap will definitely help - gotta find the problem not the symptom

CupraDave

iTrader: (1)

thanks prana
i only said it was strange as Chris described his car did the same when cold

get home next tuesday so will do the lambda thing and post up how I got on

Sc0oby

try checking for crack in your hose connection near the boost solenoid

CupraDave

iTrader: (1)

Please forgive me for sounding really stupid, I am new to subarus but where is the boost solenoid located?

It had been suggested I disconnect the lambda sensor and go for a drive. I disconnected it and went for my drive, the car felt ok for the first bit but then started missing again but slightly further up the rev range. I stopped and reconnected the sensor. Now the car does not boost as it did (it feels very weak) and now on occasion when the car hesitates it produces a dark cloud from the exhaust.

I have new leads on their way, which should arrive this week hopefully along with new plugs. I also have new air, fuel and oil filters waiting to go on when I do the oil change this weekend.

I am starting to wonder if the car was actually re-mapped for UK fuel when it was originally imported, if not then is this where the problems are stemming from?

To say I am a little worried is an understatement, I have a little savvy but am no mechanic so cant really faults find and problem solve myself. I am prepared to put in the time and effort to solve the problem but need to know what I am doing first as this is my first scoob and more to the point my first car with forced induction.

Sc0oby

also check for any crack hose under the intercooler pipings

prana

CupraDave - the car will not boost because your AM has gone right back down and you are blowing black smoke because you're running the low octane map, this means AM must be very low, could be a few reasons, either knock detected or CEL flag was set or a combination from the disconnection. Find someone locally with a ODB2 to help you diagnose and if you can, read the AM values in memory. I wish I could but I'm in Sydney

I am still not too sure about the unplug your lambda technique mentioned , but using the ODB2 will allow you to read the output voltages of your lambda to help diagnose if the sensor is working to scale. I would still take it to a good technician/dealer to have the transducer scaling checked for accuracy.