O2 sensor questions..

[db_sampson]

i have been having a bit trouble with my car for a while, fault codes are telling me its the right side O2 sensor is reading lean so i have a few questions before i replace them..

i checked all the plugs last night, drivers side are pretty black which i assume is from the computer compensating for the lean reading and pumping more fuel in to avoid the engine shitting itself completely, the passenger side looks pretty spot on to me, so i don't think there is anything wrong there, am i right that the fouled plugs are a result of the O2 sensor failing and it self compensating??

i plan to change both sides eventually but because i'm unemployed at the moment, im pretty fricken poor, there will be no harm done by replacing them a few weeks or so will there?? i know they are only 90 odd bucks each, but its seriously a stretch even for that at the moment..

anything else i should check/replace while i'm at it, obviously plugs should be done after the O2 sensor, but anything else that absolutely should be done at that time..

[bpefi]

If one side is reading lean then it is usually an earth problem with the oxygen sensors - there is other posts on this far more in depth than I can go - but basically you link the earths for the oxygen sensor

[nathanVY]

search tool is your friend

How To: Fix the VS V6 4 Wire O2 sensor earth problem – Known Holden Problem

[Brett_jjj]

Ive ran into a very similar problem with the 02 sensor readings on the early VSV6 4 wire 02 sensors.But what Ive found is that when I try to replace the original memcal file which is VS file BSTK,with the later updated VS memcal files like BTXP or later,I have found the oxygen sensor readings either stop,are very low,or are completely different from side to side,exactly the same as the earthing problem can cause.It also sets error codes like code 78 and 76 etc.The weird thing is as soon as the BSTK memcal is fitted again,the 02 sensor readings go back to normal and no error codes set..Ive tried the 02 sensor earthing fix,with no difference in the 02 sensor readings,so it wasnt that which I thought it might have been.Ive ran into a couple of other people who have had similar problems with the early VS's 4 wire 02 sensor readings but couldnt find out why(even with the 02 earth fix done).The BSTK memcal was replaced by holden for complaints they recieved about pinging,probably due to the higher ignition timing used in this version,apparently there was also a cold hesitation problem with this version,which Ive never experienced while running it.This made me think that if holden replaced the BSTK memcal for the later release while servicing VS's at the time,has it caused problems that have been traced back to the 02 sensor earths,the thing is Ive tried this earthing fix in a few different ways including the same way as the how to on here shows,and its made no difference to the readings.So I just dont know now what to think.Ive asked a few people about this no one seems to know what would cause these bad 02 ensor readings on one memcal and not with another thats for the same model car .Its something to keep an eye out for anyway if you have the early VS with the 4 wire 02 sensors,and are thinking about changing the memcal chip to a tuned VS chip.The latest versions are usually used as the base for a tuned chip.This is what Ive tried to do and have now ran across this problem.Im now using a tuned BSTK file which runs excellent now with a bit of tweaking.Ive used the later VS trans settings out of the later VS releases anyway,which is why I wanted to run the later VS updated file in the first place.Ive made the trans shift quicker and firmer as well with a few changes of my own to the standard shift settings.Its a lot better now for a standard auto box.

[db_sampson]

If one side is reading lean then it is usually an earth problem with the oxygen sensors - there is other posts on this far more in depth than I can go - but basically you link the earths for the oxygen sensor

search tool is your friend

How To: Fix the VS V6 4 Wire O2 sensor earth problem – Known Holden Problem

thanks for that guys, its something i definitely plan on checking out, i'm assuming that this would be a pretty common problem with the VS 4 wire sensors, is this generally the only cause of 1 side failing??