My 01 XJR started having a rough idle. It has about 70K miles. The check engine light came on. Then, this morning, the car wouldn't start. When I jumped it using cables, it started, but still rough idle. Once I start driving it, the car seems fine...it is just a rough idle when I come to a stop. Any help you can provide would be greatly appreciated.

 

Get the codes read.... the answers are in those codes.

 

Mike:
Dont know where you are located, but if its the US, Autozone or Advance Auto Parts will read the codes for free. (I am sure there are others, too). As Norcal said, the codes are the key.

 

Thanks NorCal and Sparkenzap for your prompt response.

So I got the codes read:
P0300
P0301
P0302
P0303
P0304
P1316

So it appears that 4 of my cylinders are misfiring. I believe p1316 is something to do with "misfire excessive emissions"

You will need to bear with me since I am not too familiar with this stuff. I am not sure if this can be related, but couple weeks ago, it said that the coolant was low, so I filled that. Then it drove fine until yesterday.

I am in the Los Angeles area...any good mechanics around here that you can recommend would also be greatly appreciated. Thanks in advance.

 

It looks like the entire A bank is misfiring. Because it is accompanied by the 1316 it is indicating excessive emissions detected due to the misfire. The 0301 - 0304 are the actual cylinders which are on the same bank, this could mean poor fuel delivery or poor spark/ignition for each offending cylinder. So to me the 1316 emissions code says it is getting fuel which is unburnt and causing the excessive emissions. Because of that I would check the wiring harness going to that bank for the coil/sparkplugs. Removing the plug covers on the top of the valve covers will expose the wiring harness for the coils/plugs. Because the entire bank is failing I would suspect the harness and everything behind that to the ECU. Where the harness passes into the sparkplug galley on the top of the valve cover is a good place to check for shorts or opens.

If your good at chasing electrical harness issues you can go further by getting a good shop manuals and finding the pinpoint harness test procedures.

BTW, the coolant has nothing to do with the misfire as far as I can tell. You might check for a pinhole leak at the thermostat housing / cap area. That was why I was loosing coolant ever so slowly.

 

i can bet that it's tensioner problem,cnain skipped. I dont think it's possible that electrical problem apeard on just one full bank. when chain skipps axaust or intake camshaft turns a little and misstiming apears. so i would sugest to take your camcovers of and check your tensioners. and ty not to drive the car or you will kill your engine.

 

Could be, but when mine skipped it just ran poor. No codes, no restricted performance, just rough running engine at all times. In the OP original message he states that it runs fine unless it is idling.

The way it is described it does not seem like a skipped tensioner chain. But if you have not replaced them yet it may e a good time to have a look.

 

Thanks NorCal and Chupacabra! They both look like great places to start. I am gonna take a look at it tomorrow and will let you know what I find.

I just bought this used a few months ago...I love the car...but I now see why folks stay away from the Jags. I had a Lexus GS before...not as cool...but almost no issues what so ever.

 

I'm with Chupacabra. Don't run it, tow it. You might just have diodged a bullet! And please report your results.

 

I hope it's not the tensioners, but if it is then you'll have to change all the tensioners, chains and all the gaskets that are needed for this operation... anyhow it's a good thing to do. so good luck and let us know what went wrong.. wi'll try to help and advise you.

 

Okay...i pulled both covers, the coils and the plugs...the driver's side looks clean, and all the wires look good.

when i pulled the coils out of the passenger side bank, i noticed that the 3 out of 4 rubber plug boots had oil on the base of them, and that there was oil sitting on top of each of the plugs.

there seemed to be no oil deep inside the cylinder where the electrodes fire. any thoughts?

Mike

 

Mike:
To fix the oil leak, you need to pull the right side valve cover and replace the gaskets and o-rings. There are different ones for different years, so be careful when ordering. While you are in there, I would sure set the crank to put the cam set alignment hole in the correct place and check the cam alignment. At least check the condition of the tensioner very carefully for damage which would indicate the chain might have slipped.

 

Does anyone know where I can get a good service manual for these cars?

 

Can someone explain to me how to take the valve cover off? So I took off the rectangular cover and checked each plug/coil...and noticed that there was oil in 3 of the 4. So I wanted to open up the valve cover to see the gaskets...however, I couldn't figure it out. I undid all the bolts that surround the valve cover along with the two that were under the rectangular cover I had already removed. However, I was still unable to open it up? Any thoughts?

Also, for the primary and secondary tensioners, what should I be looking for. Will there be visible wear? Thanks in advance.

 

as I remember there should be 14 screws totaly for cam cover, so if you undid all of them then just pull up harder perhaps it's glued with some liquid gasket or however it's called, and what you will see is chain (try to move it, if it feels loose then it is the tensioner) and two cams ( on front of each cam are flats (marks) both marks should be at the same position..allways). so if you see what you should... or what you should not see then you have tensioner problems.. and the oil: yes there should be oil when you have timing problems because.....(hard to explain in english sorry). what you can check is take off air intake pipe, and open the throttle body air intake walve (hope you understood ) if you see oil down in the throttle body then again.... yea...tensioner And if you see nothing incommon with what i've described then you're lucky. check the exausts for oil aswell

 

Mikesong, lots of threads dealing with the tensioners... just a few from my search are here. Lots of good info, and I'm sure there's more around the forums.

https://www.jaguarforums.com/forum/s...ight=tensioner

https://www.jaguarforums.com/forum/s...ight=tensioner

https://www.jaguarforums.com/forum/s...ight=tensioner

There aren't any repair manuals, you either have the JTIS CD (jag technical schematics and procedures) which you can either download around here somewhere, or order a CD from ebay...$7, or Alldata.com has a service that allows you see more technical information and parts removal/install.

 

Mikesong,

The gasket on your valve cover sits in a grove. If you take screwdriver you should be able to pop open the cover by working the screwdriver near the front of the engine. Also on the cover that is by your oil dipstick there is a metal tab from the dipstick that blocks you from lifting straight up.

 

Thanks everyone for your input. I wish I had the time to work on the car myself, but decided yesterday to just take it into the shop. FYI, it was indeed the chain tensioners.

 

case closed