I purchased my 2000 XJ8 a few months ago with a bad tranny. After the work was done, it had trouble staying running but the shop finally got going. We all thought the trouble was old gas as the car had sat for almost 2 years. I'm three tanks through with seafoam and it got slightly better. Original code was misfire in #7. The car is sluggish and goes in and out of restricted performance mode.

Plugs are new Bosch double platinum
I found oil on the air filter which is being pulled from the elbow piece in the valve cover. I was told this is a PCV. I have searched on every site and store I can think of and no returns for a PCV on that year/model. The piece that is on it is not a valve at all, it goes right into the valve cover.

CEL started blinking two days ago. Pulled the codes and got the following:
P0307 #7 Misfire
P0174 Lean on Bank #2
P1314 Catalyst Damage Misfire Bank 2/B
P1316 Misfire Rate exceeds emissions
P1384 Variable Camshaft timing Solenoid 1
P1396 Variable valve timing solenoid 2

I've read what I could so far, and it sounds like I've got a lot to check. If someone could point me in the right direction, I would appreciate it. I'm really perplexed by the PCV thing too.

Thanks

 

There is no PCV. The engine vents into the intake system through the part load breather (the small plastic pipe on the left valve cover) and the full load breather( the big platic pipe i believe you refer to). A little oil in either is ok, a lot is a sign of a bad engine.
It sounds to me like you may have multiple problems, and a little oil in the breather is a minor one. There is a chance you have a timing chain jump on yopur left cylinder bank. Prudence would say check the secondary tensioner and timing first before other troubleshooting because if it jumps more, it will bend valves and essentially spell doom for the engine. If timinmg is OK, then a compression test and /or leakdown test is in order.
When those are done, reset the codes, evaluate the results, then decide what's next.

 

Hello
Ross has given you great advice.
Check out Summary of Major Repairs & Safety Issues PDF for some of the know trouble issues of XJ8 and XJR models:

https://www.jaguarforums.com/forum/a...lance-test-pdf

This PDF file has lots of links to related posting on this forum and on the internet.

Jim Lombardi

 

Welcome -- how many miles on the car? Any service history?


What did you do to try to correct the original problem with #7 -- did you just add the seafoam? I'm not a fan of additives except maybe some ocasional Textron use on mechanical fuel injection cars.

A failing coil on #7 should have been looked into -- you can switch the #7 coil over to another cylinder and see if the code follows. You are getting additional codes that are telling you that the miss is severe and gas is getting to the converters -- you do not want to drive the car like this as you can damage the converters.

The concern now is the timing codes. With the Jaguar V8's tensioner problem it may be prudent to pull the valve cover on that side and see what is up. The engine may have been missing enough to have had the chain jump.

Does the person working on the car have any Jaguar experence?

 

It has 88,000 miles. I do not have any previous service history, but the prev owner did have some records from the dealer and I am pretty sure the timing chain had been replaced.

I did not do any additional diagnostic work for the missed #7 code other than checking the spark plugs. I just trusted the shop that the gas needed to work through and it was probably a clogged injector.

The oil in the air intake is more than a little. What worries me is that it is originiating from the passenger side of the engine, and the codes are on the other side. The oil drips down onto the air filter and there is some varnish buildup on the throttle body.

I am going to clean the throttle body and inspect the timing chain and tensioners. What did you mean that a lot of oil means a bad engine?
Thanks for all the help so far.

 

Well, what puts oil in there is that the engine blows it in. That happens primarily when the rings are shot, or in this engine's case, the Nikasil cylinder lining has failed. the compression from the cylinders escapes around the pistons, through the rings and blows the oil out. The oil is not the primary problem, but indicates the compression problem.
And... unfortunately, this is not a simple engine to rebuild. The afore mentioned Nikasil (read horror stories in the archives) cannot effectivey be replaced and rebuilding requires steel cylinder liners to be installed, which is expensive and does not have a lot of reported history of success.

 

Thanks for the response. I just pulled the air intake to clean it again, and the filter is clear so far of oil. I think it has just built up, little by little. I also gave the throttle body a good cleaning.

I pulled the spark plug from #7 (after checking a diagram, I had the wrong one last time) and it had quite a bit of oil on it and was pretty fowled. Do you think this indicates a problem with the piston rings as you suggested?

 

Could be, probably not. Clean or change the plug, reset the codes and go from here.

 

I agree, check #7 and reset the codes. If you are concerned with Nikasil and compression or blowby (oil in breather pipe) add a can of “Restore” to your oil. If the car is is still running poorly add “BG 44K” to the tank and drive the car.

 

Cleared the codes, changed two plugs and drove it for about 20 minutes with no new codes. It still idles a little rough, but it is running the best it has since I got it.

I have read on other posts that it takes some time for the computer to reset after a miss. Is that the case and could it be the source of the rough idle since I'm not getting any new codes?

Thanks for all the help thus far, I think I'm getting close to solving the problem.

 

After all that it turned out to be a bad coil pack. Its running like a dream now. Thanks again for all the input.