Hello,
Just bought a 1995 XJR. Having trouble passing emissions test. The Jag failed on HC gpm 3.7160, and CO GPM 62.6223. I Checked the codes and I am getting a P1138 lack of HO2s12-sensor indicates rich. The car always starts and runs good. Could it be the O2 sensors? Could it be that the O2 wires are mixed up? As they have the same connectors.
I just looked under the car and both brake cooling tubes were broken. They each have a sensor mounted in them(one sensor is missing). What is the function of these sensors. Sorry for all the questions just trying to educate myself on these incredible Jaguars.
Also just noticed another small problem. When I switch the parking lights switch to headlights, it causes all of the warning lights and speedo to flash. Like you are starting the car. Could that mean a electrical problem? Anyways the car has 98,500 miles on it. Thanks again in advance!

 

I know the sensor mounted in the passenger side brake vent is an exterior temperature sensor, the car will give you a readout of the ambient temperature outside when the little [EXT] button is pressed next to the climate control screen. as far as the driver side sensor, I still have no idea.


As far as that headlight switch issue, it sounds like some wire is getting a little too frisky with the other wires, and requires a little investigation behind the steering column panel and kick panel.

just grab a screwdriver and a flashlight and see what you can see; wiggle all the plugs around and see if you can't kick over some rocks.

 

Hello thanks for the reply,
I will take a look at the the switch.
What should I do about the failed emissions problem? Should I replace the O2 sensors? I checked the codes and only one was displayed a P1138. Somehow the engine is running rich. ANything I should look out for on the XJR. Only symtoms are high idle, poor fuel economy, and failed emissions(high reading on CO). Thanks again for all your help!

 

The O2 (Lambda) sensors can fail, and are quite costly at Jag prices, but are I believe also used in some Fords too, its just finding which one !

However, dont rush into replacing expensive parts before you are reasonably sure its the fault, you can spend an awful lot this way !

As said, here, the induction side could be faulty with leaking fuel injectors, engine temperature sensors, etc etc putting in too much fuel. You can check to see if the O2 sensors are open-circuit quite simply; if one or more are, then clearly they have failed.

 

Hello, Thanks for all the info! you guys are very knowledgeable about these problems.
Would the o2 sensors cause extremely high emissions. The emissions failed by more then 5 times the legal limit. Yet the engine runs really good. I did try to clean the 02 as they are so expensive. Can you clean them? Or do they just fail? Would you know what the 1138 error code means. It is a rich condition, but what will usually trip this code. I am looking at all parts and it could be anything. Fuel pressure,mas, coolant sensor, bad coils, air injection pump, I just don't want to start replacing all these parts as that can be very expensive. What things could I try?
Sorry so many questions. I just love the car and want everything to be perfect!
Thanks again Bas

 

Hello, Thanks for the reply guys!!!!!
The jag has 4 sensors, 2 upstream and 2 downstream after the cats.
Do the downstream sensors really matter? Or do they also alter A/F ratio? Sorry I am new to Jaguars.
Yes I bought a general code reader. It will not read live data. Sorry I am limited on the funds. The only thing the code reader gave me was a p1138 bank 1 running rich. The XJR smells like it is running rich. I replaced the spark plugs and they were all sooty and black. Just ordered a new coolant temp sensor.
I did notice that the idle on the car is also very high when it has warmed up(close to 1500 rpm). How do you adjust the idle speed?
There must be something that could be causing such a problem? It failed the emissions by more then 5 times the limit!!
And again thanks for all the help!!!!!!!!!!!!!!
Bas

 

high idle indicates too much air getting in somewhere, vacuum leak somewhere, gasket leak perhaps, idle air control valve, throttle not closing all the way, could be any number of things causing the high idle

 

Thanks again for all your help!
When the idle was high i fiddled around with the cable and it went back down. The cable goes into a box on the passenger side. What is this throttle piece for. It has electrical wires at the top. How do you adjust that piece. Could that piece cause an emission malfunction?

 

Before trying anything else I'd get some seafoam or other type of good combustion cleaner and do a thorough fuel injection service on the vehicle to free up sticky valves, clean injectors, and remove any carbon deposits off the 02 sensors. You do this by using a pedal depressor (or in my case a prybar or long screwdriver wedged between the driver's seat and gas pedal) holding it steady around 2500-3000 rpms. Remove a vacuum line feeding directly into the throttle body, and slowly "sip" the seafoam or cleaner in, little by little. If you do it right, it can easily take you 45min to an hour to finish up the bottle, but everything will get cleaned very well. After this clear your codes, take the car for a good ride (give it some wide open throttle and watch all the white smoke pour out the back..make sure no one is behind you!). Wait and see if codes come back...if so..then dig more into a possible vacuum leak and or 02 problem

 

btw just read your last post...sounds like your cruise control got stuck and remained slightly engaged giving you a high idle? Another thought is make sure the spring for the butterfly valve on the throttle body is nice and strong...some older vehicles tend to have sticky butterfly plates over time as a result of a weak spring or gunk build up on the butterfly plate. I had an old Lincoln come into the shop once with that exact problem and it was idling at 4,000rpm! That thing was FILTHY

 

I will try that. I really need to clean her up engine wise. I wish I knew more of this XJR's maitenance history. But a good clean up would be the first place to start. The throttle plate is going to be a lot more difficult as it is located under the intercooler. I can't even see it. The idle control thing on the passenger side engine bay looks a bit damaged. The plastic piece that holds the cable is broken. I will get working on the car as soon as it gets a little warmer. This year has been a very snowy and cold season!!! Thats Colorado!
Thanks again! for all the advice! You guys are great. Someday I will return the favor(once I am more familiar with this excellent Jag)

 

The thing on the throttle wire is the antispinn. When the ABS notice wheelspinn this will slack your gas.

The problems on your car can be a number of things. The first thing yopu should start with is checking for air leaks due to the high idle. It can also be a sticky throtle bytterfly and thats a pain in the as to clean on an XJR.

The O2 sensors have been quite faulty on these cars but i wouldnt start there. And no you cant clean O2 sensors.

Check for leaks first around inlet manifold and fuelinjectors. If Air is leaking or exhaust are leaking the sensors will show a faulty value. Without being broken so start there

 

Hello Thanks for all the info.
Hello, Yes it seems that the abs control unit is not functioning. When it was idling high, i pulled over and grabbed the throttle cable going into the control unit and then the idle went back down. Could it be the control unit? What can I do? Or should I disable the abs and traction control fuses? Would that cause a emission test failure?
Originally The CO and HC were skyhigh.
What parts should I replace.
I want to replace
1.EGR
2.TPS
3.O2 sensors
4.coolant temp already replaced
5.Need to measure fuel pressure, how do you do that
and what reading are normal?
Anything else I should look at? CAR is running way too rich.
Sorry is is just bothering me why it won't pass. I have 2 weeks left on temporary tag.
Thanks again for all your input.