quality of NB O2 these days

[The1]

dont worry, im yet to see one go up

[Holden202T]

lol!

would the fuel economy being so far out when the sensor fails be a sign you might have other issues, or the tune might just need tweaking ??

[vlad01]

no it o2. my cruise economy is whats suffering. last o2 sensor went 2 months ago. economy was falling by the day and got really bad one day and that night coming home the CEL came on. O2 failed and the economy was so bad that I used half a tank going home from work, that was a 75km trip.

Chucked in another used and known to be somewhat failing O2 and economy more than doubled but not as good as it could be as that was one of my bad O2 I had laying around.

guess what? it is this^ same o2 that is about to shit itself completely.

I bet you it will improve to 7s L per 100 when I drop a new one in. atm I am getting 12L + I wouldn't be surprised if I get a CEL on the way to the holden dealer tonight.

[vlad01]

dont worry, im yet to see one go up

mine normally doesn't move going to and from work (75k each way) however when the car is left to cool for few hours and restarted later the gauge is slightly lower than when I arrived.

trips under 30k sees the gauge go up a little as I drive as things warm up.

[delcowizzid]

i replaced one in my vx ages ago with a used ebay cheapy that came out of my turbo vn its still going hard fuel trims on 1 side +/-1.the other side ive never changed and its stuffed takes ages to come back to life after lean cruise mode and is trying to add 30% LOL.and now my cat is stinky on cold starts smells like someones shit themselves in the back seat.time for another O2 and a CAT delete

[vlad01]

i replaced one in my vx ages ago with a used ebay cheapy that came out of my turbo vn its still going hard fuel trims on 1 side +/-1.the other side ive never changed and its stuffed takes ages to come back to life after lean cruise mode and is trying to add 30% LOL.and now my cat is stinky on cold starts smells like someones shit themselves in the back seat.time for another O2 and a CAT delete

yeah mine smells rich a lot of the time now.

[Jayme]

dont worry, im yet to see one go up

mine normally doesn't move going to and from work (75k each way) however when the car is left to cool for few hours and restarted later the gauge is slightly lower than when I arrived.

trips under 30k sees the gauge go up a little as I drive as things warm up.

you know why that is.... hot fuel. hot fuel in the tank makes the resistance go up in the fuel sender.... more reisstance = higher reading.
due to this holden inverted it in the VZ. in a VZ the guage will be higher after the car cools down.

[festy]

dont worry, im yet to see one go up

my patrol's does when I flick the switch to pump from the sub to the main tank

[Holden202T]

no it o2. my cruise economy is whats suffering. last o2 sensor went 2 months ago. economy was falling by the day and got really bad one day and that night coming home the CEL came on. O2 failed and the economy was so bad that I used half a tank going home from work, that was a 75km trip.

Chucked in another used and known to be somewhat failing O2 and economy more than doubled but not as good as it could be as that was one of my bad O2 I had laying around.

guess what? it is this^ same o2 that is about to shit itself completely.

I bet you it will improve to 7s L per 100 when I drop a new one in. atm I am getting 12L + I wouldn't be surprised if I get a CEL on the way to the holden dealer tonight.

what im getting at is, if your O2 is screwed and the ECM throws up a CEL from it, that will mean your most likely running in open loop, ie. off the VE table with no correction from O2 sensor.

Now if said VE table is spot on it shouldn't matter, but the fact fuel economy is changing so much tells me something is out of whack, so if you were to put a brand new O2 sensor in and fuel economy improved back to normal then take a look at BLMS from a few trips and see how much they are changing to compensate for incorrect fuelling, thats the only thing i can conclude from what your seeing.

if your ve table is 100% perfect you shouldn't really notice any change from open loop and closed loop fueling this is why you disable BLMS when tuning to make sure its not influencing the outcome.

[vlad01]

what I found is the o2 can deteriorate a fair bit before the ECU decides its stuffed and then throws a code. Always has been like this for this car.

Some of my familiy's fords are worse, they don't even have CEL for dead o2.

Anyway I have got me a new genuine AC delco o2 from holden at a surprising $47.

going to the fuel station now, 1.5 trips to work and I am on reserve from nearly a full tank


will know tomorrow how it goes.

As for the BLM, with the NVRAM fitted ECU showed most were about 95 to 100% around with VN s1 tables in most areas where I cruise and light load throttle, so pretty much right. As for the memcal thats in there atm, I have no idea. its a greenfoam tune, but results it the best economy. even better than my attempts to tune as I didn't have a WB at the time and I don't have a VP spark table, only VR or VN s1, they certainly don't have the correct spark table for this engine and I can't be bothered doing all the work when this car will be replaced by the VR in a few months anyway.



btw I always thought the ECU defaults to a richer mixture when closed loop can't be achieved?