O2 sensor replacment

[eskimo]

Hi,

Replacing the O2 sensor this week in my AE111(20v BT) just a few questions

1-Do I need to check the ohms or something of the old one to make sure I get the correct replacement one (read that somewhere on here when searching) . I called part master to order the new one and all they asked was, was 2 or 4 wire and the car frame number etc"

2-Do I resent the ECU after replacing it, and is this done by disconecting the battery for a period time, a few mins etc?

Cheers
JH

[sergei]

Hi,

Replacing the O2 sensor this week in my AE111(20v BT) just a few questions

1-Do I need to check the ohms or something of the old one to make sure I get the correct replacement one (read that somewhere on here when searching) . I called part master to order the new one and all they asked was, was 2 or 4 wire and the car frame number etc"

2-Do I resent the ECU after replacing it, and is this done by disconecting the battery for a period time, a few mins etc?

Cheers
JH

It must be same type (heated, zirconium). They work as voltage source, so measuring resistance is pointless. If it is of the same type (btw it is the most common type), and it is heated (prefferably) you will be fine (apart from fiddling with wiring).

You will need to reset ECU to let it relearn fuel trim. Pull 15A EFI fuse out for ~10-15sec.

[eskimo]

Sweet cheers for that, so I can leave the battery connected?

[Mr Revhead]

You will need to reset ECU to let it relearn fuel trim. Pull 15A EFI fuse out for ~10-15sec.

how slow are ECUs to react to new sensor info?
Assuming no stored code.

[sergei]

You will need to reset ECU to let it relearn fuel trim. Pull 15A EFI fuse out for ~10-15sec.

how slow are ECUs to react to new sensor info?
Assuming no stored code.

It is hard to tell, but a week or so will be enough to alter long term fuel trim.

[AceSniper]

if you get a 4wire universal you might have to weld a threaded nut in to fit it, Some come with a flange so you can just bolt it on but that flange is normally a lot more $$

[matt dunn]

Also a lot of the more modern cars (and I think AE111's are like this)
measure O2 sensor heater element current though the ECU to ensure that the heater circuit is working,

and so you do need to get one that is around the same heater resistance.
not exact, but close.

[eskimo]

Sweet thanks for the input. How do I find out the heater resistance?

[Mr Revhead]

You will need to reset ECU to let it relearn fuel trim. Pull 15A EFI fuse out for ~10-15sec.

how slow are ECUs to react to new sensor info?
Assuming no stored code.

It is hard to tell, but a week or so will be enough to alter long term fuel trim.

http://www.4x4wire.com/toyota/4Runner/tech/OBDII_ECU/

some good info there about it. Taught me things (which I will probably forget in two days )

[sergei]

You will need to reset ECU to let it relearn fuel trim. Pull 15A EFI fuse out for ~10-15sec.

how slow are ECUs to react to new sensor info?
Assuming no stored code.

It is hard to tell, but a week or so will be enough to alter long term fuel trim.

http://www.4x4wire.com/toyota/4Runner/tech/OBDII_ECU/

some good info there about it. Taught me things (which I will probably forget in two days )

Those O2 oscillogramms look fake to me. I mean the writer couldn't bothered to hook it up to real O2 and simulated conditions, instead it looks like they used a sine wave generator and fiddled with scope to give the picture they wanted.

This is what real live O2 reading looks like,






And definitely not:


Being pedantic here.

[MAGN1T]

Ideally you should be using a genuine part.
Those aftermarket universal ones are pretty much rubbish and don't last particulartly long. They don't output the exact same voltage either.

Yes those oscillograms ARE fake, it even says so. So are yours, due to A to D conversion errors / sampling rate.

Steve

[eskimo]

Ideally you should be using a genuine part

Yeap, have got a TGP one now. Went to get the one from partmaster and it did infact need a bit welded on to it to fit so flagged that & just got a TGP one.

[sergei]

Ideally you should be using a genuine part

Yeap, have got a TGP one now. Went to get the one from partmaster and it did infact need a bit welded on to it to fit so flagged that & just got a TGP one.

Good choice. I once went the route of aftermarket. It lasted only 1 year. Then I bought genuine and 7 years later is still goes.