wrx

Conected it up today soldering all three wires to the ECU plug wires. It's a MY00 euro import and I was told that the oxygen sensor wire was pin 21 on the blue plug (white with silver stripes I think).

Drove the car for 10mins and no lights came on at all. So checked with a multimeter and the pos/neg wires were fine but the oxygen sensor wire was only giving .006 volts and didn't change when I raised the revs. So have I got the wrong wire or is my sensor broke (how do I find out).

The other strange thing is with just the pos/neg wires conected and the ignition on, the blue light is iluminated then when I touch the sensor wire to pin 21 on the ECU it goes out and no lights are on (presumably due to only reading .006 volts) then if I take the sensor wire off for 20 seconds it goes red/amber/green/blue and stays on blue with nothing conected to the sensor wire, how does this happen as surely it needs to be conected to get a reading.

Please help

sti-spec-a

Blue light is normal when signal wire is disconnected I wired my signal wire into the sensor in the engine bay Originally when i fitted it the thing would barely register a signal I directly earthed it to the battery It gave a better signal but not 100% Turned out my Lambda sensor was guffed With a new lambda it gives the "Knightrider" effect pootling about and Green/Blue on WOT

P S it does sound as if your Lambda is guffed because the voltages at the sensor would fluctuate when you rev the engine

Grant

wrx

thanks for that.

Where is the cheapest place to get a new sensor from?

Dark Blue Mark

WRX,

I took a long time to email you instructions to fit it, and no reply of thanks?!

MB

Dark Blue Mark

PS, lambda sensors nearly always fail rich, so tend to give permenant 0.9v

It should take no longer that 10 mins to warm up before it starts bouncing.

How old is the sensor? Secondly, a failed MAF can also play havoc with the readings. Do an ECU reset and see if your idle goes haywire.

MB

wrx

Sorry DBM I only have access to t net at my parents so had only got the mail yesterday when I was pulling my hair out as to why it wouldn't work. But many thanks. If I do an ECU reset and the idle goes haywire how do I then stop it from going haywire? If the MAF was buggerd wouldn't it run bad? It runs better than it ever has since putting the dawes device on and now gets 27MPG instead of 22MPG I just want to get this AFR working to see if I can run more boost.

Where can I get a new oxygen sensor from? Mines just over 4 years and 45K miles old

stevem2k

You are probably running lean then because your MAF is buggered.

Steve

Dark Blue Mark

More MPG and feeling faster are symptoms of a lean mixture, which is normally becuase the maf is gone. The car will feel quicker and quicker - then bang. You would think it would run bad, but the clever ECU learns its way around it. Resetting it will cancel the learning and reveal lots of bad idle type symptoms....

Not to alarm you

Get the dawes off until you have the MAF checked. With those miles, I wouldn't be surprised at all if it was dead. What filter do you have?

Would deffo do the reset too. A new MAF element is about £90 on these from dealr btw.

MB

wrx

Is the reset, just disconect the battery for an hour? and is this what I need or where can I get an oxygen sensor from?

I have an brand new air flow sensor, which is still in the Subaru Box, the part number is 22680AA271. Think it may be for a 22B, but not sure.

Dark Blue Mark

If its for a 22B it will be a whole MAF and the plastic tube housing, and wont fit. The MY99/00 Subrau realised just how bad them MAF was and designed it so you could just take the element out. Do a search for ECU reset. It can be done with 2 pairs of connectors under the dash, or battery disconnect.

Take heed on the driving safely on boost (or not at all!). The MAF governs the fuelling when over 0.5 bar. This is very risky if its running lean.

MB

wrx

did the ecu reset (disconected the battery for 1 1/2 hours) and the car runs the same as before (idles perfectly and the car stalls when the MAF is unpluged) so I think it's just the oxygen sensor failed. So as long as the MAF is ok the PPP ECU should be supplying plenty of fuel I guess. Am getting a new oxygen sensor tomorrow and will get a Knocklink asap. I only ever run it on optimax and NF so hopefully it's running on the rich side

Thanks for the help.

Dark Blue Mark

Good stuff. If there's any odd readings on the AFR after the o2 is relplaced, let me know...

I would give the OB a miss if I were you. Unless you remap for it, its a waste of money. It wont richen the mixture, just alters the properties of the fuel - mixture is adjusted by the 02 sensor.... There is a difference.

Knocklink is V good re-assurance, never felt confident without mine...

MB

wrx

Fitted the new oxygen sensor and on start up get red and yellow lights (green if its been outside overnight) the red while cruising and yellow on WOT I'm sure others have said that thiers lights up like a christmas tree when cruising so is mine getting a good reading? I had to cut the conector off the sensor as it was for a different MY and couldn't be arsed waiting for another one will this give me low readings? The wires were all solderd and heat shrinked individually the same as the ECU conections but I did use inline conectors to make the AFR wires longer (should these be solderd aswell?)

As I've fitted the dawes device is anything controling the fueling or is it just on a set map? and if I turn the boost up more will it adjust the fueling itself. Obviously if I see a red light on WOT I know thats bad and to turn it down.

The_Judge

It should be able to fuel accordingly, up to a point. But I'd strongly advise getting your Knocklink before adjusting the boost. Your AFR gauge doesn't sound as if it's perfect. Yellow on WOT sounds a bit on the lean side. This is where the Knocklink comes in useful, to save you second guessing the AFR gauge. I only use my AFR gauge to reassure me that my lambda and MAF sensors are OK...

Dark Blue Mark

WRX, ignore what it does at startup. Once its warm, after 10 mins. Does it slowly bounce back from lean to rich at idle and a bit faster back and forward at cruise?

When you say the sensor was for a different MY, are you sure you have the right one, with the right number of wires?! I personally dont like connecting the AFR there, as the lambda wires are not solderable.

Re the fuelling, as Jundge says, the ECu will control the fuelling to a point, but if you add too much boost it cant keep up. This is where a remap comes in.

Do a bit more research before you keep fiddling, its easy to break it. Also take heed of what Judge is saying, KnockLink is the best bet beore you do what you're doing and it is best used to see if your sensors are ok, not to indicate engine health.

MB