OK then guys,
finally had a chance to get a proper look under the car today and I have a problem. Well, I have lots of problems but only one I wish to address with you guys!

The cat has been removed at some point and a straight pipe has been put in its place. This in itself is not a problem. What is a problem however is I have no idea what it is supposed to look like under there!

I have two o2 sensors pre cat and a random sensor with two wires 'where the cat should be'. So I thought it was another o2 sensor, but from what I can gather the straight six only has 2 at the pre cat stage. Can anyone confirm what this other sensor is and even better get me a part number?

I may have found another reason for the lumpy idle as well, the exhaust manifold is cracked and blowing in many places and it had three gaskets between the manifold and the block.

The parts required list gets longer and longer!

Just to clarify it is the straight six 4.0l supercharged XJR I have, not the V8. I think that may be where some of the confusion comes from on my first thread ref the misfire.

 

I'll confess that I don't know but I'll bet a photo would help those who might.

 

Good Call, heres a pic of the offending sensor in situ with the two o2 sensors. I would get one of the sensor itself but it is welded into the exhaust!
I also attached a pic of the old girl as I have not put any up yet.

 

Well,
The old adage of seek and ye shall find comes true once again. Managed to get JTIS working on my new laptop and low and behold I find this snippet of information in there:

Apart from two heated oxygen sensors, the exhaust system for vehicles destined for the Japanese market are also fitted with two exhaust gas temperature sensors (5 Fig.1).

Now, mine only has one, but it is also missing a catalytic converter so that doesnt surprise me.

I cant find anything specific to Jag, but other makes info tells me that removing the sensor will cause no problems as its not connected in any way, shape or form to the engine management system. Can anyone confirm?

 

On most vehicles its there to protect the cats, and if its not sending a signal or if the signal is too high indicating high temps the ecu will make the car run rich to cool the cats and your power and fuel economy would suffer. Unless jaguar only used this sensor to light up the warning light on the dash I would say that their proper operation is very important.

 

You may find that the JEPC(Jaguar Electronic Parts Catalogue) download is also helpful as the pictures can sometimes be much better than the ones in JTIS.

 

[QUOTE=mevans;502089

Apart from two heated oxygen sensors, the exhaust system for vehicles destined for the Japanese market are also fitted with two exhaust gas temperature sensors (5 Fig.1).

Now, mine only has one, but it is also missing a catalytic converter so that doesnt surprise me.

I cant find anything specific to Jag, but other makes info tells me that removing the sensor will cause no problems as its not connected in any way, shape or form to the engine management system. Can anyone confirm?[/QUOTE]

I know of the Japanese "overtemp sensor" on many brands of cars. As I/we are not in the Japanese domain, actual hands on with them is limited to zip.

This came up many, many times whilst employed in spare parts departments, and I believe it did light up the dash light, and on some cars an audible alarm sounded, but I reckon Jag was just a light, as a warning??. I am not aware of any fueling alterations, BUT, it makes sense. I dont believe the ECU will have a hissy fit without it actually connected.

Many of the Japanese private imports here simply have that sensor unplugged and no ill effects that I know of.

 

Thanks guys,
Had a good old dig through the electrical diagrams and the exhaust overtemp sensor does just put a light up on the dash. There is no connection to the ECU. So for anyone who finds themselves in a similar situation, just pull the sensor. It will have no ill effect on the car.

Now to figure out why JTIS service diagrams shows only two o2 sensors, but the wiring diagrams show 4?! Any ideas guys?

 

OBDII cars had four, the others only two ? That's my take, at least.

Cheers
DD

 

I thought it had sensors before and after the cats so it could tell if they were working?

"The combustion gases, after passing through the exhaust manifold, enter the catalytic convertor (13), where the quality of the exhaust gas emission is modified. The quality of the exhaust gas emission is constantly checked by the Heated Oxygen Sensors (H02S) (14), which are situated both upstream and downstream of the catalysts. By comparing the signal outputs of pre and post catalyst sensors the ECM can make corrections to the fuel and ignition settings as necessary. The sensors contain integral Heaters which accelerate the warming-up of the sensors to enable a rapid correction
of initial settings which may be causing the emission of low quality exhaust gases."

Jaguar Classic Parts (.com) says you should have two LHE1682AA on a 3.2 or 4.0, unless your car is in Emission Group A (which is stated in the VIN I think?), in which case it says three LHE1682AA and two LHE1682BA on the upper rear downpipe.

 

Ah, but Jaguar classic parts doesn't know I have a Japanese spec car! This has confused me up until today when I finally found the information I needed buried deep inside JTIS.
Japanese spec cars only had the 2 upstream o2 sensors plus 2 cat overtemp sensors. Im sure if I was in Japan or spoke Japanese then figuring this out wouldn't have been a problem, but as I don't its been a nightmare!

Think twice before buying a jap import jag. Its completely different to everyone elses!!!!

 

There is at least one member on JF that is based in Japan ... you might be able to find him and make friends.

 

AHA, my Aussie spec X300 3.2 has 2 upstream sensors ONLY, and that is the same for most cars in our market.

The USA market had the 2 downstream as well that I know of.

The Japanese, well they were just "different".

Doug is also correct with the OBD2 bit, that I know of. Mine has the port, but VERY limited info via it.

 

My XJR is ex-Japan. It has downstream O2 sensors only. It also has temperature sensors per the photo attached, note the O2 sensors are not fitted in the photos.

 

sounds like you are having a bit of a nightmare!..... I'm in Abu Dhabi too, and have a XK8.... I'd like to talk to you regarding servicing and repairs if you don't mind....

 

Paul, sorry for the late reply. im actually living in UAQ, but will be happy to help if I can. What do you need to know?

Slowly getting to the bottom of the problems, hope to have her on the road by the end of the month!

 

Ahhhhh thought you were in Abu Dhabi...... Wanted to know if you had knowledge of any 'good' garages that have experienced Jag technicians .... But PM me on paulbell@emirates.net.ae and I'll give you a ring.....