New here - need O2 sensor
 

I just put a 1986 CRX HF back together runs good but i need an O2 sensor for this car and the part has been discontinued and I cant seem to find any info on a replacement

I have an 87 CRX HF and I had the same issue a few years ago when I was getting it back on the road.

Since these early HF oxygen sensors have a smaller diameter than the standard size, I would think that you could drill out the hole in the exhaust manifold and tap it for the 5 wire civic VX sensor (92-95). Cast iron is easy to drill and tap- just be sure to get the hole straight so the base gasket can seal correctly.

Does it take a 5 wire? And if it is an odd size an Exhaust shop should be able to weld a nut on that's what you do. You don't drill and tap you drill a hole and weld a "bung" on. Good luck.

I agree that welding a bung in would be the best way to add an O2 sensor to a thin steel pipe- but cast iron can be really challenging to weld properly (I am by no means an expert welder, but it is tough for me when I do it) and there is a risk that applying that much heat unevenly in a small area will crack it it (unless you preheat the whole large item in an oven).

Cast iron parts are drilled and tapped after they are poured and cooled so drilling and tapping is a normal process for this material.

The location of the O2 sensor on his car would be very easy to access with a drill and tap- that is why I suggest this method.

Is the wiring the same colors on both O2 sensors? Just cut and splice?

No an exhaust shop could do it you need the right rod and yes you drive the car get the Mani hot and still preheat it with a rosebud torch. Or just switch to a different setup aftermarket style.