Scott.T

iTrader: (2)

Bumbling through the Subaru EPC for an 02 STi, it looks as though the front 02 is in the header, the rear 02 is in the bottom of the DP and the EGT is in the up-pipe.

Can anyone confirm this, as am looking at a car tonight that has a suspected Lambda fault

cheers...

Midlife......

iTrader: (2)

The Newage STi's have no EGT sensor..the EGT sensor grief is a WRX only problem

AFAIK the location of the front and rear lambda sensors is correct

Shaun

Jolly Green Monster

iTrader: (4)

yeah correct and then the one on the stereo or is that lambada?

Scott.T

iTrader: (2)

cheers guy's
the car in question comes up with a 02 sensor fault using ECUExplorer but I am lead to believe that ECUExplorer and Delta Dash are poor at retrieving the correct codes due to ever changing locations.

the car is idling fast which makes me think it's more like a ISCV issue.

AndrewC

Or an airleak somewhere.

What is the code?

Midlife......

iTrader: (2)

LOL JGM No, it's Richie Valens on the stereo ..La Bamba

When I blew my Lambda it came up as an O2 heating circuit error....I have also had a failed ICVS and The cost of replacing that made my nose bleed

As andrewC mentions what's the CEL code ?

Shaun

Scott.T

iTrader: (2)

Just logged it and the rear 02 sensor doesn't seem to be outputing any voltage.
Rear 02 also came up on ECUExplorer and ECUEdit as an error.

Idle AFR is off the scale, but once you come off idle AFR is fine.

I'm not sure how these lambda's interact on the 01> cars, but my guess would be the rear is used to set idle AFR in some way.

Everything else I could think to look at works OK i.e MAF, thottle %.
Although not sure what the ISCV % should run at, but it was 16 at idle.

The car is low milage and barley gets used, so doubt it's a air leak.

Jolly Green Monster

iTrader: (4)

not sure I understand you theory on the low mileage and barley used therefore not an air leak.. if a pipe wants to come off or split it will..

However it is telling you what the problem is and you are still unsure what is wrong?

Simon

Midlife......

iTrader: (2)

The rear 02 sensor is to check for catalytic converter efficiency and throws CEL P0420 if it thinks anything is wrong (cat below efficiency).

This CEL does not affect performance in any way as it is ignored by the ECU it's just a real pain if you de-cat the bugeye but can be re-mapped out

The front 02 sensor is a pseudo wideband jobbie to handle the open loop side of things but along with the newage MAF seems pretty robust !

The Idle on my MY02 bugeye has always been flakey compared to my 1987 Toyota MR2 which never changed in 15 years !!

The other problem is that the bugeye seems to throw CELS for no reason....Mine used to light up a camshaft position sensor error and then a misfire CEL....... not to mention the dreaded neutral position sensor error

sorry if not very helpfull

Shaun

Scott.T@PolarPerformance

Well AFR was 23 at idle and running around 2000rpm
As soon as you come off idle even in the slightest the AFR dropped to 14.7.
when cruising AFR was still set at 14.7AFR, when boosting AFR dropped to 11.2AFR at WOT. so all as expected.
But as soon as you drop to idle AFR went silly again........

If it were the ISCV i would expect idle to be a bit ropey but it should still be trying to achieve 14.7AFR.

Simon, I am only unsure of what is wrong as I am lead to believe the software available for reading out the error codes on the Subaru ECU can tell lies due to the amount of ECU variants and the changing loaction of the error codes.

Plus I don't want to send the owner to subaru to by an expensive part if it ends up not being at fault.

Jolly Green Monster

iTrader: (4)

some assumptions..

your tail pipe adaptor is not picking up all the exhaust fumes when the gas speed is low such as on idle, so the engine is not actually running 23:1AFR.

The error code reader is showing a fault on the rear O2 sensor and you are seeing no voltage from it.. so it is confirmed as a fault.. not a rogue error code, if the voltage showing from the rear sensor was sensible then yes you could class it as a rogue trouble code but it is confirmed by the fact that the voltage is incorrect!

that is calling out for the suggestion that perhaps the superior EcuTek software should be used rather than what you are using.. tongue in cheek..

Simon

AndrewC

What is the error code?

Has the car been modified?

Have you done the std failing MAF/O2 sensor test?

Scott.T@PolarPerformance

apparently deltadash is just as bad.

AFR at idle on every other tailpipe that I have shoved the probe up has always been ~14.7AFR

As this car is using the same tailpipe as I have I am happy it's reading correct.

The front 02 sensor was also reading an AFR of around 20...and in lambda is was around 1.6(ish)

The rear 02 sensor does not get converted in this software to AFR but was reading pretty much 0V but had at some point gone as high as 0.5 during the test run.

the car in question is an 52 Plate STi type UK with TSL 333. Has been running fine for a number of years, but the current owner hardly uses it. it started playing up a few weeks back when he got it out of the garage to take it for a service.

As mentioned above by midlife, I wouldn't expect the lambda to cause idle issue and raised rpm. but then I'm new to 01> and how they behave with sensor failures..

Andrew,

No I haven't doen the 02/MAF check...whats this ? disconnect MAF ??

AndrewC

What is the error code?

What's the TPS reading at idle and the manifold pressure?

Scott.T@PolarPerformance

Not sure what the error code was, just read the text description output from ECUExplorer

TPS reading was 0% at idle and rising nicley to 100% when WOT.
Not sure about manifold pressure at idle.