Greetings everyone,

Our XKR has recently failed to pass Emissions Test. When the car was idling, the CO emissions were sky high, but at steady 2500 RPM's, the emissions were inside the legal limits here at Spain. We only have had the car for a bit over a year, and last owner passed emissions test without any trouble at all. We wonder if, as the car was kinda stopped for a while until it was sold to us (and we have only put like 4k miles on it), some of the sensors may be gone bad and so. The exhaust tips have collected a good ammount of soot this last year and smells like running rich.
The OBD2 says we have two error codes: P1646 and P1647. Looks like the engine is running quite rich, but there aint no issues of bad idling, bad performance, no engine light is on, etc... We got the car a new battery and new tires, and it runs really smooth.

All I can find after reading tons of info, is about these errors related to O2 sensors, upstream if I'm not mistaken. We are no experts.

Any clues about what could be wrong? I CAREFULLY cleaned the MAF sensor, and thats all I've done to the car. We know what we have to get fixed in the near future for sure (tensioners!, water pump, chains, belts, hoses...) thanks to this forum members and all the great information here.

I have contacted the official dealer here and asked them about the price to get the 4 sensors (upstream and downstream), and they told me that they want to charge us 300 euros for each sensor (just for the sensors alone, no labour, etc).... really overkill, as a fast google search found me the same DENSO sensors for 67 euros each....

These are the sensors I beleive are the ones the car uses: (jaghelp.com)

Denso 234-9016
Denso 234-4798

I sent these "part numbers" to the dealer, and their answer was with these "part numbers" instead:

LNE1682BC
LNE1684BB

These last two "Part Numbers" are the ones I could find on google easily available.
Are these the right ones to purchase?
We would love to get the car back to legal road status, but we are a bit lost here. We dont have a trusty car shop, and the official one is so expensive that it becomes a joke, plus I've read bad things about their mechanics (badly paid, low experience young mechanics, part swappers, etc).

Any suggestions are welcome!

 

It would appear that like owners of these older Jags in the rest of the world, the dealer is not the place to go. I'm not sure of the part numbers, but using the Denso parts is the least expensive way to get quality parts, and finding a independent shop to perform the work would be best. Your codes refer to the upstream sensors.

I hope that there will be a member that can refer you to a shop in your area. Try posting on the Europe forum for help:

Europe - Jaguar Forums - Jaguar Enthusiasts Forum

 

Before buying any parts have you checked the fuse and relay for the oxygen sensors? You can find the electrical diagram for your car and many other useful documents here:-

JagRepair.com - Jaguar Repair Information Resource

To check part numbers try the SNG Barratt website - they also have a European branch if you want to order from them.

Finally there is a Spanish Jaguar forum where you are more likely to get some local recommendations than the largely dead Europe forum:-

https://www.forojaguar.com/foro/view...211244b0f4eeca

 

I'm sorry to say that I haven't looked as closely as I should before posting, but will.

But, If you look specifically for early XKRs you'll find that a code for p1646 is POSSIBLY pointing to one of the 2 fuel pumps. The other p1647 may be a sensor issue - for sure. Before dropping a ton of cash (or any at all) determine (which I believe is the case) that you have the 2 fuel pump set up and that on your car the p1646 flags for that, and not an O2 sensor. If you perform a few searches using GOOGLE, typing in year, make and model followed by the codes you'll get lots of juicy results.

It could be that you only need one sensor. All failing at the same time is a rare thing.

 

Will do! Thanks for your input.

I have checked the O2 Heater RELAY as I found its location on the "electrical guide".
It has tested OK.
I couldn't find which of the fuses is related to the O2 sensors.... so I tested every fuse that I found at the "trunk fuse box".
All tested OK.
I also tested the Fuel Pump 2 RELAY. Tested OK.

So, it seems like both of the O2 upstream sensors have failed?
Keep in mind that the car was probably stopped during some time, and that both could have been "gone" during the "last years" with its previous owner, as without O2 sensors, at least what seems here, the car runs perfectly smooth.... but high emissions (only at idle, at 2500rpm it was legal).

Thanks for your input!

I did search and read all the posts about O2 sensors I have found here and everywhere possible.
It seems that there's a debate whenever the code really refers to the O2 sensors or the secondary fuel pump, which is not clear at all.

I did read about unplugging the fuel pump 1 and see if the car runs with the second fuel pump, but that it would need to involve driving around, so I dont really like the idea of getting stranded at the middle of the road in the city. Is there any other way to test it? By listening to it maybe?

Since my main problem is related to emissions, and due to my low knowledge about mechanics.... could all this be about the O2 sensors?
I will check the air filter, but I doubt after one and a half year it could be that clogged enough to cause these huge emissions on idle.
The car seems to have full power despite all, its like a rocket when kickdown is pressed....

Thanks everyone for your input.

 

Greetings people.

I have checked the O2 Heater relay located at the engine bay, and it tested OK.
I couldn't find the location for the O2 Sensor Fuse/s, so I checked each and every single fuse located at the trunk. All tested OK.
Is this specific fuse located somewhere else?

I did read every single post about O2 sensors here and everywhere on the internet, but due to my low mechanics knowledge and all, I dont know if the O2 sensors could be the cause to my high emissions (idle only, at 2500rpm its perfect legal).

Aside from that, I have checked the Fuel Pump 2 relay and the trunk, and it tested OK.
I did read that it's unclear if these codes could be related to the O2 sensors or the fuel pump. Seems no one knows for sure.
Is there any way to test the Fuel Pump 2? I found somewhere where they said to disconnect the Fuel Pump 1 and run the car around and see if the engine stalls at some point, but doing that around the city ain't so inviting to me as to get stranded at the middle of the road somewhere, as it can be dangerous and etc....

The car runs smooth and powerful, no issues, My problem is not being able to drive it legally because high idle emissions...
The air filter was installed new one year and a half ago. I dont think it could be dirty and clogged enough to give these high emissions, would it?
That can be checked very easy anyways...

Thanks everyone for your input! I will try to seek for help and find a proper mechanic shop around here....

On a different topic.... Is there anything that could be done to limit the engine RPMs? This is, to avoid mechanic dudes having fun with the car as I had bad experienced about this in the past and I dont trust any mechanic to drive such a beauty,

 

Think this one through with me. You unplug fuel pump 1 relay - it stops - no gasoline coming from it car will stall in a second or two if thats the only pump able to provide gasoline (FYI this is how I depresurize my single fuel pump before changing the filter).

Now with an XKR that has 2 fuel pumps, pump #2 will take over all gasoline delivery instantly if its working when fp#1 is inoperative..
Maybe I'm missing something obvious but why would you have to drive it anywhere? I think this is all about isolating each pump to see if car runs on it alone.

Hope it helps
John

 

The electrical guide also tells you exactly where the fuses are - its worth spending some time studying the electrical guide to understand all the information it contains. According to the wiring diagram for my 2001 XKR the O2 sensor fuse is in the Engine Management fuse box, near to the relay (i.e. under the bonnet, not in the trunk). If you have identified the relay you can always test for power at the relay socket to be sure.

 

All right, so I have tested the Fuel Pumps, and both do work properly on theirself.
I have checked for power at the O2 heater relay socket and it tested OK.

So my bet is on the O2 sensors gone bad and need replacement.

Thanks everyone for your input. I'll try to find someone who can swap them and hope it fixes the codes and emissions.
Will keep you guys updated.

 

Greetings fellow Jag lovers.

I had the official dealership repair shop swap the two upstream O2 sensors (1400 dollars...) and now the car seems to run the same as before, just that the smell coming from the exhaust has changed. We attempted to pass emissions test, but failed again, this time due to LAMBDA emissions.

The CO emissions are perfect now, however.

Before the swap:
*CO emissions idle: 4,79%
*CO emssions @2500 rpms: 0.02%
*Lambda emissions: 1,060

After the swap:
*CO emissions idle: 0,00%
*CO emssions @2500 rpms: 0.00%
*Lambda emissions: 1,504

- The acceptable range for lambda emissions here is between 0,97 – 1,03.

I've been reading a little about the lambda emissions, and looks like they go higher when the engine is running lean?.
I would say it was running rich before the O2 sensors swap.
All I can think about is looking if the exhaust has any sort of "hole" somewhere where the air comes in, I dont know...
Anyways, I'm wondering to swap all the spark plugs, clean the ignition coils, change oil, and air/oil filters.

Any input is welcome. Thanks!

 

So, what is the test? Here in the US, emissions tests are, to my knowledge, "software only". i.e. the inspection station connects to the computer over OBDII and reads the existing status. The car tells the inspector if it is ok or not.

For cars pre OBDII (before, say, 1996), we have a sniffer test, with a sensor measuring the net emissions out of the tail pipe, for a given set of conditions (load, rpm). The car is strapped to a set of rollers to simulate the road, etc.

Our cars are definitely OBDII, so OBDII test should be enough. Have you checked if you have code P1111 or P1000?

PS: In technical terms, the upstream sensors you replaced are wideband sensors. There are also 2 narrow band sensors, aka lambda sensors, located further downstream (sort of midway down the cat converters).

 

1400$$$$!? Is that translated into US Dollars? What's the equivalent US, if not? I'm sorry, and don't mean to rub salt in wounds BUT the upper sensors can be changed in minutes. Literally, minutes. And, if you compensated these folks to that degree,,, for the reason you did, do they have any responsibility for running the car thru some tests to see if the repairs bring things into spec? Anyways

In my experience it is necessary to do a hard reset (or run the car for a fairly significant period) for the ECU and it's stored information to begin to adjust to the new sensors... If you are willing to do it yourself, this is how I do it:

disconnect the negative cable on the battery (since you are in Europe be sure of radio code as I think euro cars have a radio code), turn the key to the full on position, then and touch and hold the negative cable to the positive post on the battery with + cable still attached... Hold for 30sec to a minute and/or longer. If not comfortable with that,,, just clip the two cables OFF the battery together and leave for a good while with key in the ON position.... This should erase all old O2 sensor input information (and other stores emissions info) and allow you to begin from a clean slate so to speak.

I find it very unlikely that all of these sensors went bad at once... Fire them mechanics... I am having less less and less love for mechanics...

 

Its a sniffer up the exhaust pipe at 3,000 RPM in neutral - they don't connect to the OBD.

 

We get a sniffer up the exhaust pipe, as "dibbit" said. I belive its measured at both idle and 2500 RPM in neutral.

Yes, I have checked a few times and the OBDII tester reports no codes, so seems the O2 sensors swap have solved the initial P1646 and P1647 error codes, CO emissions are great now, but lambda value is high.

Yes, I got swapped the upstream sensors, but not the downstream ones... The parts were quite pricey. Each upstream sensor had a cost of 280 US dollars. I wonder If I should have swapped those as well...

Yep, 1400 US Dollars....
I dont have a pit or any special toolings to make the job, and also after reading every single post about the O2 sensors, It looked like it was a realy PITA to get to them, get them out and swap new ones in.... Can they be really changed in minutes? They took around 5 hours...
I told them not to drive the car, just to swap the parts (I dont trust mechanics driving my cars... bad past experiences on this).
They just said that they thought that the engine is not running smooth. But I prefer to investigate myself on the matter and try to fix all I can by myself before throwing at them 136 US dollars per hour labour.... I been attempting to find an alternative repair shop, but have found none where they could service cars like these for now. I used to have a trusty repair shop for 30 years, but the main dude has retired (he used to work with all the racing stuff, F3000, ferraris, porsches, lancia delta integrales, mitsu EVOs, race track cars, etc...

I did the hard reset, took back the clock, windows, gas pedal and radio to the "normal operative state", and went for a drive yesterday.
The car runs smooth in my opinion, but I cant compare to any other XKR or XK8.
I belive the car has lost some power, I cant be 100% sure, but I think it wasn't as fast as before the sensors swap.
I didnt want to push it so many times, but I floored it twice for at least one full gear to a max of 100mph.
I will have to drive it again, because when I went back home, I was wondering If I could not hear the supercharger whine during the test.
Checked for codes again, after stopping the engine twice during the ride, and no codes are shown.
I noticed the exhaust smell has changed since the sensors swap.

About the sensors going bad at once. I guess the previous owned didnt care much about these codes, and maybe one went bad some time ago, and the other went bad some time after the first one, or who knows when. I remeber that these codes showed up since I bought the car (I didnt have an OBDII code reader by then).

So to sum up:
it seems the car is running lean now?.
All I wonder now is to swap the spark plugs and see what state the old ones have, change oil and air/oil/fuel filters, and clean the ignition coils.

Thanks everyone for your replies!

 

You might want to consider installing one of these :

Autool X60

then you’ll know for certain if the car is lean running or not.



it just plugs into the OBD-II port and can give you instant readouts of fuel trim numbers as well as many other engine parameters such as oil and coolant temperatures, charging voltage, MAF function, etc etc. Mine has been in use for 4 years and has proved invaluable for keeping all systems go.

AUTOOL X60 Car HUD Automotive Display Head Up Display Multi-Function Digital Meter Alarm Speed Water-Temp Gauge Malfunction-Test for 12V OBDII Petrol & Diesel Vehicles

 

Hi!

I just ordered the AUTOOL X60, and hopefully will be here in around 9 days.
I will need some help to figure out how to check all about the "fuel trims" and "maf", so that I can find out if the car is running lean.
I haven't got a clue of how to proceed about understanding what "fuel trims" and "mass air flow" numbers can mean at all, and what numbers to expect to be correct or not. I'll be reading around to understand what fuel trims mean.

Thanks for your input ZRAY!

 

You might try reading this thread. It cleared up a lot for me.
FAQ: Fuel Trims Thoroughly Explained

 

Feel free to send me a PM of you have any questions about the X-60 operation. The instructions are on the vague side. Poor translation I suppose.

Z

 

Thanks for that link clyons! It has helped me understand better the insights.

Will do! Hopefully I will be testing it next week. I'll let you know how it goes, and post the data so we can see how the engine is running.

And aside from that, I'm really going a bit nuts on finding "proper" spark plugs after reading stuff for like 8 hours...
My engine is an AJ27, and at the vehicle specification "book" says that the original spark plugs were AJ8 4575 (iridium), with a gap of 0.9 – 1.0 milimeters or (0.035 – 0.039) inches.

Do you all know for a proper spark plug (NGK or DENSO) OEM (part number) that comes with the right gap and all for my cat?

For example, I found a NGK IFR5N10, but the gap is 3,5mm... I'm having trouble finding a proper spark plug...

Thanks everyone!

 

that gap must be a misprint. The NGK laser iridium IFR5N-10 plugs are the correct ones and work perfectly as factory gapped in my ‘02 XKR.

I either bought mine from RockAuto.com or Amazon,

as you can see from the Amazon ad, they come gapped at 0.040”. Perfect.

NGK 7866 IFR5N10 Laser Iridium Spark Plug


https://www.amazon.com/dp/B00TD6ZJ9Y/ref=cm_sw_r_cp_api_glt_i_E8BSY0ZNGA1QCS13TE6H