speedy steve

Hi there,

1995 WRX wagon, recent decat DP, & ECU remap (ESL) no other mods, been running fine for a while despite a brief "smokie" stage which I thought was the turbo on the way out but a quick oil change to something a little thicker seames to have sorted that....

well new problem, fuel economy has become drastically worse, during my daily commute ( most of which is sitting & crawling in tailbacks.. ) i.e. off boost driving, have checked my MAF by the "unplug during tickover test" instant cough splutter & stall which is a good sign. ( I think ? )

next most likely candidate would be the Lambda sensor, which I will attempt to test this week, assuming its KO'ed would one of these work ?

"http://cgi.ebay.co.uk/BN-Universal-4-Wire-Zirconia-Oxygen-Lambda-Sensor_W0QQitemZ120035554071QQihZ002QQcategoryZ722 05QQrdZ1QQcmdZViewItem"

seams mucho cheaper than the other options I have found so far ( local Halfords no longer stocks L300 universal )

Have I missed anything ? is it worth trying to wirebrush & no-trich degreaser the old sensor to bring it back to life ?

I know that around £30 aint much if the sensor will fix the problem but it is potentially about 100miles of fun !!!!

SS

speedy steve

Tested lambda output at weekend, once engine hot, probed connector with following results :-
0.3 V varying to max of 0.36 V at tickover

by blipping throttle worked revs up to max ( 6k ish ) maximum reading of
0.56 V

responce seamed very slow as well i.e. good second between any form of reading change.

I take it this means the sensor is definatelly goosed ? , have ordered a super cheapo generic 3 wire ( zirc ) from E-bay for £15 which will confirm for sure.
( if the cheapo sensor only lasts 6mnths as others have experienced then so be it. )

SS

StickyMicky

what reading do you get on boost?

should be around 895mv IIRC ??

or it might be 885mv it should be a bit higher then 560ish i *think*

speedy steve

Hi Sticky,

Didnt try under load, only stationary, short multimeter leads etc but I could hook the meter up a little more permanently & try again while driving.

Do you think this would tell me anything else ?

SS

StickyMicky

you could have a fault with the fuel pump maybe?

they are renowned for going off slowly with age, although from what i have gathered, they tend to run lean as they get older, mine did.

I suppose its possible it could be going icky, chances are its probs your lambda

speedy steve

Hmm now I'm really cofused, just changed out lambda sensor for a new one, appears to read bt 0.7 & 0.75v all the time ????? regardless of throttle position ? ( all tests still stationary no load ) , maybe the "new" one is worse than the original ? any ideas would be appreciated..........

vulnax999

iTrader: (7)

Should cycle between 0.1 - 0.9 v each second when on closed loop running in low load conditions, e.g. idle. Around 0.8v something is stoiciometric point - spot on air/fuel ration.

Lambdasensor.com do Bosch LS200 universal, and a Legacy /universal one with a Subaru plug on the loom ( which may fir some years of impreza ) for £45 - £57. Lots of info on lambda sensors on there web site too.