2003 XKR
DTCs - P300, 302,304,306,308,1314 & 1316

Hey guys, After fixing a minor fuel leak on a perfectly running car that required mucho work to fix, I'm still having massive troubles with cyl bank 2 missing on 2,4,6 & 8. Obviously the car runs like dog doo doo.

The Short Turn Fuel Trim Bank 2 is -25.8% at idle. Plugs 2 & 8 are really fuel fouled after only 5 min of very poor running and code throwing. All 8 COPS are good and I have swapped banks all COPS.

After a second complete removal of the supercharger and its charge-air coolers I have confirmed the full correct operation of all injectors (they were professionally cleaned) I swapped banks with all of those too. Also, I cleaned the MAF sensor carefully when I re-assembled the engine for the 2nd time.

Before I lay out all the sordid details of my 6+ week ordeal (so far) I'm trying to cover ALL my bases BEFORE I lay this very frustrating problem at everyone's feet. Now, my research and due diligence is pointing toward a possible clogged bank 2 catalytic convertor or a bad pre-cat oxygen sensor.

Okay, I guess I'll bench test the O2 sensor... So I take the time to remove the left side pre O2 sensor out of the convertor and I CAN'T FOR THE LIFE OF ME find where the wire goes to disconnect it!!!!! Aaaaaaaahhhh! This can't be this hard! The wire bundle goes up above the center of the tranny and disappears !!!! Where in God's name does it go? I can't find where the right side goes either (both vaporize into an invisible and unreachable abyss above the transmission.)

I don't deserve this - somebody all-powerful is laughing at my floundering.

I'm a really good self-taught mechanic. I've owned 65 motor vehicles in the last 35 years - and have not taken a single one to a professional mechanic since I was 17 years old! I've fully restored two 60s muscle cars, a rotary rocket and two motorcycles, rebuilt at least 6-7 engines and four transmissions, and... I'm an electronic engineer. But this car it beating the crap out of my brain and confidence.

Can any one tell me HOW to get to the O2 sensor connectors?

Pah-leeese.

 

It does go to the block on top of the gearbox, all 4 sensors are connected there, sorry have no pictures.

 

Be very careful to note the exact wiring colours to each one before disconnecting the sensors.

If the XK8 is like the early XJ8, the sensors are connected at the factory and then configured with the Jaguar WDS. Getting them mixed up is a nightmare in the making.

Don't ask how I know that!

Graham

 

You are having a God Awful time here, I really feel for you.
If you want to take it the 500 miles to Indian Head I'm sure my friends there would gladly donate 10 kg of C4 and solve this car's problems for good!

 

Here are the instructions for getting at the connectors excerpted from my write up on upgrading to the Nameless Performance Cats. Hope it helps:

-- Set up very bright lighting pointing behind the throttle body.

-- From the right side of the car, locate the four oxygen sensor connectors. All four are behind the throttle body, in the main firewall harness area. All four are most accessible from the right side, but it is a very tight squeeze back there. There is a grey and a black four wire connector for each of the cats' two oxygen sensors. Three are in line right up near firewall, and one (the grey one from the driver side cat) is 90 degrees from the other three, within a bit easier reach from the driver side. They are extremely difficult to un-mate while on position on their mounting tabs. Instead, lift each connector pair straight up off its metal mounting tab. They will pop off with some direct upward force. Once off of the tabs. there is enough cable slack to squeeze the locking tab on each connector body and un-mate all four connectors.

 

Steve,
This is a bit OT but Graham suggests the O2 sensors are factory configured.
Does that mean replacement involves a re-configure?

 

To my knowledge there is no configuration needed on the XK8/Rs, but as Graham says, it is important not to mix up sides.

 

Thanks.
Hope you don't mind - I'm going to copy your unplug instructions to a new post so I can add a link in the 'How To' section.
This question has come up several times since I've been here and yours is the best answer (actually it's the only answer but 'best' sounds better).

 

That is some pretty awesome power you have there Steve !!

 

As I've said before, us Steve's know a thing or two!

 

(late reply - been to the Jaguar Graveyard for parts)

No need for any reconfigure provided the leads are connected to original or replacement sensor positions exactly as found.

Graham

 

It's on my list of things to go wrong so I'm grateful for the advice.
Sorry, Maxwdg, back to your topic

 

Thanks for the quick replys, guys - and bless you White for presenting your experience with doing exactly what I'm going to attempt (again) tonight. Since I plan on taking a close look into the left convertor and to do so, I have to remove it - do you (WhiteXKR) think that I'd have more access to those connectors above the transmission with the convertor out of the way???

Believe me Steve, if personal integrity didn't get in my way, I'd consider your advice with the C-4. My father-in-law is a main ka-hoona in a large mid-west city's "bomb squad" and my access to C-4 may be slightly better than most... You know, they do have to "dispose" of quantities of "hot" material several times each year - who's to say that a certain green jag may not "get in the way" next disposal time?

Those thoughts aside, the thought that bugs me the most, is that the car was running perfectly when I took it apart to fix the fuel leak. I have put it back together (twice) with the assistance of a 22 year old friend that won second-place in Missouri's ASE automotive diagnostician contest for High School kids a few years ago. So I'm 100% positive it's reassembled correctly and without damage to any components whilst doing so. What are we missing that could have suddenly "gone wrong" with this car?

I hope I'm "barking up the right tree" by looking at the bank 2 Oxygen sensor and convertor. Any other suggestions?

 

What are the values (so stft and ltft) on Bank A? Just want to be sure that Bank A is perfect, so that the cause should be searched for on 1 bank only. Sometimes it could be that 1 bank is just below the thresholds, and thus doesn’t show any codes, but there could till be a common cause (or more than 1 problem).

Assuming Bank A is perfect, chances are indeed something is wrong with the A/F monitoring. You may want to check O2 heater relay first, so you could swap it from the Bank A, before swapping sensors (which I am afraid might be the best next step).

 

Hey AVOS thanks for that tip. That's a good suggestion - now all I have to do is look up where to find those relays...

The STFT and LTFT for Bank One are around -1 to 0%. In fact the car has not be run enough since this problem has showed up to even effect the LTFT for Bank 2.

Cheers,

 

I still think it is easier to get to from the engine compartment than under the car. Not 100% sure however if my instructions from a 2001 map exactly to your 2003.

 

White, you were right on point. There's a row of four connectors all mounted vertical directly behind the throttle body partially hidden by a huge conglomeration of wiring harnesses, right up against the fire-wall.

I'm a bit embarrassed that I didn't realize that those were the four O2 sensor connectors before I asked youse guys! I must say, in my defense that all the wires from all four sensors are loomed together back under and behind that connector panel and are visually completely obscured. When you give a cable a slight tug the invisible loom keeps them together and that certainly made me think that they were headed into unreachable territory. My bad.... but thanks for the clarification Mr. White!

Now.... I have good and bad news. After a bench test with a propane torch, I'm fairly certain that the pre-cat O2 sensor is good. I was getting .98 volts when it was hot and .1v as soon as I took the flame off the sensor. That seems "good" to me. I never thought I'd WISH that I had a bad sensor - but, seriously, I really WANT to find the source of my problems!

So... I spent an hour at 1-2am trying to remove the convertor in order that I can establish whether it is clogged or not. I said TRYING because, Damn! The exhaust system clearance is soooo very tight that just removing the convertor is requiring me to remove more of the exhaust system than I was expecting. And while laying on my back with the floor of the car just four inches from my nose, it's kinda tough going.

Oh well, I'll get that ******* off later this evening.

 

As far as I know measuring just the voltage isn't a good way to test the wide band sensors. They work based on current flow, contrary to the post o2 sensors which ate of the narrow band types. Don't know if there is a method to test them of the car.

 

Jeez Maxwdg, please could you send me a bottle of your Patience Pills ?
You are a real Hero. Hang in there and sort the b*trd
C4 sez I.

 

So, AVOS.... Do you advise buying a $160+ part on a wish and a prayer?
Just to find out IF the sensor is bad?

I'm not saying that I'm adverse to to tossing that kind money at my baby if there's a good chance that I was aiming the propane torch at the root of my problem last night. I just don't want to blow dough for a long shot. I read a lot of "testing 02 sensor" material on the internet last night - as well as watching about a half dozen videos of mechanics claiming to be bench testing their O2 sensors. I thought I was doing it right. There has to be a way to test the Wide Band sensors.... I hope.

In the event I do decide to replace the sensor: Anybody have advice or thoughts on whether or not the less expensive Bosch sensors can be successfully used in place of the megabuck Denso units on our cars?

Thanks Steve - my patience come from my stubbornness. This car WILL NOT BE MY UNDOING! And I love driving it.

Peace, and thanks to all following my unfortunate plight.