I need some info on O2 sensors. The smog mechanic was telling me that some O2 sensors have holes and others do not. He said it is very important to use the right one. Can someone elaborate on this? I replaced my O2 sensor years ago and cant remember if the old one had holes or not. I think the new one did.

Also, on my 1994 Jag xjs there is only 1 O2 sensor after the precats. Should there be another before somewhere? It seems like all the parts cattalogues are wrong for my car. a 1993 Jaguar xj6 seems to match perfectly in precat style and placement of O2 sensors. I guess they changed mi-94...

Anyway, thought I would start a thread all about O2 sensors. I keep failing CA smog.

 

I only see 1 O2 sensor on my car. After the Pre Cats and before the rear cat. Is that all there is on an OBD1 Car?

 

hoodun,

Have you got an AJ6 4 litre? Your signature seems to imply that you have a 6 litre XJS?

If you have got a 94 AJ6 car, then there's one O2 sensor fitted (AFAIK). If you've got an AJ16 (April 94 onwards) then you'll have 2 sensors (in the UK).

I'm not sure what you mean by a "pre-cat". Is that a US phrase? The sensor(s) is / are fitted after the catalytic converters which are in the downpipe. I know that some US-sold Jaguars have some sort of pseudo-cat which is in the exhaust system after the downpipe. We don't have those here. I think they are not "real" cat's but a slimmed-down version of something. The real cats are always in the downpipe.

I'm not sure which parts book you're looking at but Jaguar's own parts diagram seems fairly clear on how many sensors you have depending on whether you have an AJ6 or AJ16 XJS. See here:

Power Resistor and Heated Oxygen Sensor - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK

Hope that helps.

Paul
Paul

 

He probably isn't talking about the holes in the guard around some o2 sensors, but rather the hole at the end of five wire wide band sensors and 4 wire ratio sensors.

These were introduced in 1994, so your car may use them, but the plugs don't match up with other types of o2 sensors, so a mistake is unlikely.

I know you can buy some universal fit stuff and splice it however you need, but if you just stuck it right in, you probably don't need to worry about that part.

Just pull the one and see what it looks like. If its fouled you will no it isn't working properly