mx5cartalk.com

Accuracy of Widebands

so when I changed over the 1.6 to the 1.8 my Wideband crapped it about the same time.
So got a new one.
but the new one seems so much more accurate than the old one. In hind sight... I feel the old one was never really accurate & made the whole tune run very rich. fuel consuption was massive.

I'm using a Bosh 4.9 with a Innovative LC 2 controller unit

Mine comes in different grades - I have an AFR500v2 with an NTK calibration grade sensor. It was pretty exxy, even at the then-prevailing USD exchange rate, but my tuner reckoned it was good insurance. That was the mid-grade NTK sensor (production, calibration, lab), the lab grade would have way more than doubled the base price with the LSU 4.9, an extra US$450

What was the one that died on you?

Running rich should have been dialled out on the dyno, using the dyno's sensor to calibrate it. Did you have someone check the tune on the dyno? On the other hand, maybe the sensor was dying over a period and just pushing it progressively richer until it finally curled up its toes ... .

never had anyone check the tune on the dyno.
the one that died was also a bosh 4.9

I will get this engine on the dyno once i have the big cams in.

My 4.9 died at a very young age, I replaced it and no trouble since. I suspect what killed it was having it heated before an engine start, apparently condensation from a cold engine start can thermal shock the heated sensor. I used to have ignition on to fiddle with ecu settings. Now I just immediately start the car. A more elaborate solution would to be use an output from the ECU such as RPM>400 to drive a relay which then supplies power to the Wideband O2 sensor. More wires!

Red_Bullet wrote:My 4.9 died at a very young age, I replaced it and no trouble since. I suspect what killed it was having it heated before an engine start, apparently condensation from a cold engine start can thermal shock the heated sensor. I used to have ignition on to fiddle with ecu settings. Now I just immediately start the car. A more elaborate solution would to be use an output from the ECU such as RPM>400 to drive a relay which then supplies power to the Wideband O2 sensor. More wires!

Mine's just wired to a switch.
If I want it off, I just flip that and no concerns.

hks_kansei wrote:

Red_Bullet wrote:My 4.9 died at a very young age, I replaced it and no trouble since. I suspect what killed it was having it heated before an engine start, apparently condensation from a cold engine start can thermal shock the heated sensor. I used to have ignition on to fiddle with ecu settings. Now I just immediately start the car. A more elaborate solution would to be use an output from the ECU such as RPM>400 to drive a relay which then supplies power to the Wideband O2 sensor. More wires!

Mine's just wired to a switch.
If I want it off, I just flip that and no concerns.

Did I read somewhere that not being heated and then exposed to the exhaust stream that they get damaged by contaminants, it's not something I've looked at for a few years now.

Red_Bullet wrote:Did I read somewhere that not being heated and then exposed to the exhaust stream that they get damaged by contaminants, it's not something I've looked at for a few years now.

I think it's something to do with them getting clagged up with carbon and stuff, where the heat helps stop it from sticking.
or something like that.


But yeah, mine's always on anyway, the only time I switch it off is if i'm in the car listening to the radio without the engine running (mine powers with acc, rather than ign, since I couldnt be bothered finding a switched ign source when I installed it)