545svk

Hi. I have a 87 auto , first delivered in Hong Kong.
At some stage the exhaust was modified to remove a resonator box (I think - see pics).
What struck me when I removed the exhaust is that there is no oxygen sensor or place for one. There is a copper tube connected to the left hand header ( pic)
I don't think the car ever had catalytic converters, but it does have a disconnected air pump.
Should a '87 have an oxygen sensor?
Thanks

G.P.

My Australian delivered 87 S4 has an oxygen sensor mounted at the front of the catalytic converter.

DuncanF

My UK delivered 87 S4 does not have a cat or oxygen sensor. Mixture is adjusted with a potentiometer next to the LH / EZK units.

Duncan

Hilton

Its geography dependent. From memory, HK cars have the same emissions equipment as UK, so no cats until 1990.

Easy way to tell is to have a look on the right-side end (assuming RHD) of the ABS controller, above the CE Panel. If there's a screw potentiometer attached to the side of it, then your car had no cats from the factory. There are other hints too, like what happens with the EGR flow behind the smog pump (it plumbs into the exhaust ports, instead of the cats), and no hole in the floor to pass the sensor cable and grommet through, as well as an O2 sensor connector bridge plug to ground the signal wire, and a coding plug on the LH.

I've fitted O2 loops to a few ex-UK non-cat cars - my current '89 has one, altho' my current '87 doesn't, its completely stock.

Pic and info I posted years ago:

https://rennlist.com/forums/928-foru...g-from-me.html

545svk

Thanks for the info and picture. I'll dive into the foot well and have a look.

928cs

Or, just check if your car has the 299 equipment code, that means a catalytic converter fitted to an automatic gearbox 928.

Speedtoys

Curious, what about Japan market cars?

Hilton

Japan market S4's have cats - but the cats are a little different.. same catalytic converter part, but they've got a neat stainless metal plate underneath to make them look tidier, and also have post-cat temperature sensors which light up a light on the dash cluster labelled "EX" which indicates an exhaust temp issue (but it unrelated to the EGT sensor-driven ignition monitoring system).

I've got some japanese cats in the garage.