DJ

Hi
Does anyone know how to manually adjust the misxture an a my93 legacy? Mine has just failed MOT and yes I have checked the o2 sensor, wiring, ECU links etc.
Could it be that I have got to change the ECU
Dick

Pavlo

hmm, could be maf sensor, or most likely O2 sensor. THere isn't a manual adjustment, and the ecus rarely (if ever) go wrong.

Paul

DJ

I have replaced the o2 sensor with a subaru one. There is no indication that it could be the MAF (rough running CEL etc.) but I have cleaned it and checked the wiring.
Any other ideas?

scoobyboy

cataylst maybe?

Pavlo

if it's running rich, this should show up on the lamba reading for the emissions test, if it's just hydrocarbons then this indicates oil problems, such as over filling.

do you have the results data to hand?

Paul

DJ

The results were not printed from the test but it failed on the fast idle test with a lamda of .93 (.97 -1.3 is the pass range) the HC was 96 i think.
This is a rich mixture, i think, but whatis causing it? and more importantly how can i bring it down?

Any ideas greatfully persued.
Dick

UkLegacyT

check for any slight blowing on exhaust joints etc. the tinyest of gas leaks and the lambda reads incorrect. it will make a pig of the emissions.

Pavlo

Leaking inlet hoses causing air to be sucked in the MAF doesn't know about. Leaking exhaust.

can't think of any other obvious ones now

paul

Pavlo

actually that would lean it out.

ecu should run it in closed loop on idle and fast idle, so I don't know what's fooked, except the lambda

Could be faulty lambda wiring.

Paul

DJ

On fast idle (2500+) i am getting a reading from the lamda sensor of .7 ish volts and it does not usually seem to be cycling up and down much (perhaps .8 -.6 V) as it does at below 2000. If however i hold it at 2500+ for 30secs to 1 min then it often starts to cycle. Could it be temperature related in the exaust? if so why is the ECU holding the lamda high?
As an aside is a sump guard fitted to the Legacy my93? It seems to be drilled for one like my old L series but has not had one since i have owned it. I ask 'cause it could alter the cooling of the exaust. It also has the origional exaust which does not leak but is well rusty.
Any ideas will be used
Thanks Dick

Pavlo

no sump guard

I too have a legacy, M reg

are you measuring with a DVM or lamba-link style meter. DVM is often too slow as it averages voltage out.

Paul

[Edited by Pavlo - 10/13/2002 8:19:10 PM]

NutterKam

Paul, I got my grey Legacy on the road this weekend and I think I've fried the universal O2 (which some people said would happen). It ran ok for a few hours but now only seems to be reading lean side of stoich permanently. The noise form the Blitz tho....

DJ

I am checking with a home made LED lamda link type device that i made from instructions posted on this site so i don't know what the response time is but i assume it is fast enough to cope with the half second cycle that is, i think, what is evident.

DJ

Kam
I may have a spare subaru O2 sensor once i have fixed my problem.
Dick

NutterKam

I'm interested defo. As regards your prob I have no idea what it could other than that already stated. Could be a dead cat if you say the zorst is old and rusty.

DJ

bttt