AE92 MAP 4AGZE o2 sensor help

[inertia]

I'm on the hunt for a 4wire for my 4agze, catch is I've just put on a new exhaust, which uses headers designed for a 4age... and the gze o2 is stuck in with rusted and rounded bolts...

3 other issues stoping buying a gze replacement or cutting out my orig:

o2 flange for the headers is 44mm bolt spacing, gze is 54mm.. won't fit.
o2 placement is on one of the primary pipes on the headers.. gze is just before cat.
o2 is probably 150,000k old and the car's fuel economy isn't what it used to be.


I was under the assumption that i get a 44mm flanged 4wire from an autoshop tomorrow morning and that's it... does anyone know the MAP AE92 4AGZE o2 specs?

Is there any issue with using the sensor hole placed in the primary pipe?
- won't this just mean it won't need its internal heating element for very long?
- maybe I should get one with just the two/three slits instead of fully holed?

General Q:
What is the purpose of placing the o2 sensor as far back as possible, why do some cars have the sensor close to the exhaust ports, on a single primary, others sniff all 4 from a distance?

Thanks muchly.

[BeRad]

From my knowledge using the innovate wideband sensor,mounting it in the collector would be best and around the 3oclock or 9oclock position to stop condensation damaging the sensor, if it is one runner i would assume that it would be inaccurate as not all 4 runners will be the same, but being a stock ecu and not being so critical, it should be ok, i would mount it wherever it was mounted in the stock headers and replace the sensor.

Being 4 wire they are heated so can be placed further back but before the cat. Although when on a dyno the a/f sensor is in the tail pipe, Either find a sensor that will fit in the bung, or get a bung welded in to suit the sensor.

[the_random_hero]

As has been said, just get a bung welded on there. It's a really, really easy solution.

[inertia]

Thanks guys,

So you'd advise plating up the sensor mount on the single primary pipe and then weld in a new mount in the secondary before cat.

Will have to find a 54mm flange type mount from somewhere, or get a screw in bung type 4wire sensor.

[BeRad]

Just go buy a bosch 4 wire sensor, they are just a round thread, and any plumbing/hose/fitting shop will be able to sell you a weld in "socket" is what they call them. Get one with the thread the sensor has.

There cheap, as most commodores etc use that sensor.

[inertia]

Will go a bosch four wire universal.

Hung up one 2 things.

12w or 18w heating element.

ground isolated or grounded thru the sensor body?
- I'm checking the ecu pinouts to see if the ecu grounds the sensor or not.

Will then have to work out what wire does what, there's 2 black, a white and a blue wire off the gze sensor.


Bung should be a universal size, most o2 catalogues don't list the bung size for their universals... will double check though.

[the_random_hero]

Will go a bosch four wire universal.

Hung up one 2 things.

12w or 18w heating element.

ground isolated or grounded thru the sensor body?
- I'm checking the ecu pinouts to see if the ecu grounds the sensor or not.

Will then have to work out what wire does what, there's 2 black, a white and a blue wire off the gze sensor.


Bung should be a universal size, most o2 catalogues don't list the bung size for their universals... will double check though.

M18x1.5 AFAIK. Only different sort of O2 sensor I can think of is from a NA VL.

[inertia]

Thanks mate, that's what I'd come up with too.

I'm thinking I'll get the bosch universal with isolated ground and 12watt heater... need to confirm the resistance of the existing sensor's heater then the voltage it runs at (I presume 12v, but could also be lower, from this i think i can work out the wattage required.)

I'm tipping it's isolated ground, I base that on nothing..

[inertia]

Bullet has been bit..

Will report success, though failure could take months... will try and remember .

-Wattage. GZE's heater resistance = 6.5ohms, assuming 12v = 22w. (18w is better fit).
-There is a wire in the harness going to ground, so went with isolated ground model.

Bosch Universal Kit with 18w heater, isolated ground. M18x1.5 i believe, will confirm.

[inertia]

Put it in today, no codes thrown from the ecu... will see how it goes over the next few months.

Wiring, basically it's Type 2 on the bosch universal's chart.

sensor:
blue to black
gnd:
white to grey
heater
black to white x 2.

Headers/Secondaries have to goto ceramic coating now, won't get a chance to see how it goes for a week or two.

[inertia]

Car drives fine, in fact, the exhaust is awesome .

Wiring seems to be correct, no codes thrown during driving and the car behaved normally during warmup.