stedee

iTrader: (4)

every couple of days my cel light comes on when either slowing down or idling

it first happened a after say a 40 mile run on the motorway , just cruising btw, and then i drove for about 5 miles in traffic then the cel come on. i drove the same journey in reverse about 30 mins later - nothing.

its happened a couple of times since - always the same - usually warm and going slow.
ive done a code check and its the knock sensor

its a v4 sti just 3" exhaust, everything else standard, oh yeah i use 99 ron

i am going to fit a walbro anyway but could it be the fuel filter is a bit ****, just seems strange that it does it on idle, should be grateful it doesnt ever do it when i put my foot down

any ideas

steve

karenv7bell

i have v7 wrx cell all way comes up cam position sensor , even though it brand new ? so i ask my friend an auto electrician to help me lol . and he sorted the problem it was some thing down in the passenger foot well , i will ask what it was , as it was more a wiring thing than an engine issue kv7 , it definitely was not the fault shown on error code . my bro works 4 main dealer and has access to tech hq as hes the technician at were he works , 15 yrs at Subaru ,

Splitpin

Code 22?

No octane booster?

Code 22 is triggered by the knock sensor input going either open circuit or short. There's clearly no way for the fuel filter to influence an electrical issue. It's also possible for a defective airflow meter input to indirectly cause the knock sensor error on 99-00 ECUs. Whether the same thing can happen on the 97-98 I'm not sure.

There are any number of possible reasons for that - for example a loose connector or fractured wire that happens to be aggravated by the specific vibration frequencies the engine generates at idle speeds.

Yikes, that's not quite the safest way to look at things. The ECU is telling you (repeatedly) that there's a problem of some sort with the sensor that tells it when the engine is performing beyond safe limits. "Being grateful" you don't see it under load is a bit... cavalier. In the non-Vauxhall sense.

The safest option with anything like this is to find out what's causing it rather than repeatedly ignoring it. "Putting your foot down" is probably not the best thing to be doing until you're sure the ECU is able to detect and respond to any pinging that might be going on. Ditto the possibility of the MAF input dropping out.

stedee

iTrader: (4)

thanx splitpin ,i`m glad you answered, ive seen all your technical posts b4 obviously know your stuff.

yeah its a code 22
octane booster, i didnt think that would be necessary tbh
i thought knock would happen at higher revs if it was true knock or under load like in 5th going up hill.
i will test the knock sensor, can they still be knackered if it reads the right resistance?
and do you know the pin outs on the ecu to check the signal from the maf and what the voltages should be.

thanx - bows - not worthy

Splitpin

It's an import likely to have been mapped on slightly better fuel than V-Power or Tesco99 so if you're running a knock detector and know it's okay, that's one thing. If not...

They're the likeliest times but it can happen elsewhere too - especially when you have complicating factors like mapping for Jap fuel or possible sensor malfunctions.

It's always possible to get an intermittent fault that only exhibits in the car, but it's less than likely. Not sure which type of sensor you have on the 98MY. If it's the 22060AA070 type, you should see around 555Kohm (+/- 25K) across the two pins and zero ohms (i.e. dead short) between the right hand pin and the metal part of the sensor body.

If it's the older type with the captive lead, afraid I don't know what the typical impedance should be - theory states it shouldn't be too different from the above, but stand to be corrected.

Oh - check for physical damage (i.e. cracking) round the sensor body too.

Pass on the pinout but if you find Slipstream_UK's manuals thread you should be sorted - and for typ voltages too. You need to exercise a bit of judgement with MAF voltages though as there's such a wide ballpark of legitimate numbers that it's usually pretty difficult spotting a broken one simply by looking at a meter. Normally the only way to spot one straight off is to log it with the car being driven and check that the voltage properly echoes rises in engine speed/air pressure.

stedee

iTrader: (4)

thanx again
i will check the knock sensor tomorrow but ive got a few things i think it maybe, the idle as always been low, not rough but low, ive adjusted it a tad higher incase that particular frequency doesnt sit well with the knock sensor

and more imortantly the jub clips around the maf piping werent that tight my theory is that when the turbo sucks it seals the pipes shut but when not under any suction it could leak abit and therefore the maf isnt registering that air - long shot i know

davoid

Did you ever solve this? I've got the same problem on a MY97 JDM wagon. Been getting steadily more frequent. Only low speeds, only when warm.

cheers
dave

phil1981

iTrader: (5)

do you often do your journeys in reverse