G'day Gents:

I bought another Jag, my first XK8. It's a beautiful black 2000 with 93K.

Beginning my drive from Baltimore to NY the "Restricted Performance" light came on. Several times while accelerating out of toll booths the engine stuttered badly. The light would intermittently clear at highway speed.
I bought the car on eBay from 250 miles away and the seller did not disclose these issues. The "Low Coolant" light is on too but I think that's just the "bobber" in the overflow tank. The check engine icon was also on.

I had the codes read and here they are:

-P0171B Bank 1 System too lean
-P0174B Bank 2 System too lean
-P0300B Random Multiple Misfires detected
-P0301B Cylinder 1 misfire detected
-P0303 Cylinder 3 misfire detected
-P304B Cylinder 4 misfire detected
-P0455 Evaporative emmissions sytem leak detected - gross leak no flow
-P1316 manufacturer controlled ignition system or misfire

The engine was also down 4 quarts of oil this morning! The seller said he topped off all the fluids and I didn't bother to check the oil level before the drive, my bad. (It's possible he didn't check the oil and it might have been low to begin with). The water temperature and oil pressure gauges read fine the whole way home though.

My mechanic said the low oil could have triggered some of the lean codes. I added oil and cleared the codes and have driven it around locally today, and so far so good.

One of the members here, Steve, saw my post on Jaglovers.com and reminded me this is a better forum for XK8's. Steve suggested it might be vacuum hose leaks, and/or oil leaking from the valve cover into the spark plug holes.

With the oil loss I'm thinking this might be a good guess.

Anyone else have some thoughts on what these symptoms and combination of faults might point to.

Thanks!

Tom

 

Hey Tom...welcome to the forum !!! Congratulations of your new acquisition...the second black beauty to come on the forum this week!

See: https://www.jaguarforums.com/forum/s...028#post313028

 

Welcome, Tom -

You may have a leaking inlet duct - the corrugated part between the air filter box and throttle body is prone to cracking. This will make the engine run lean since the airflow is measured as it exits the filter box. My duct now has self-fusing silicone tape over the cracked area and the engine runs much better.

Mike

 

I was thinking that, too. I was also thinking that maybe the inlet duct has just gotten loose and popped off of the throttle body. It might be sitting loosely on the throttle body and then letting in too much air when going over bumps or accelerating.

 

The new inlet pipe is 66 from the dealer. I fixed mine for about $12.00.
Just a 6"to 8" length of plastic pipe from pep boys. it came with the silicone sleeves but I had to buy 4 breeze clamps to install. Just cut out the corrugated part. the silicone connections will give enought movement in the snorkel to allow it to still flex under acceleration.

 

looks like they have you going in the right direction new guy. Lean codes, coupled with either entire bank or both bank misfire, are often related to inaccurate measuring of the air and fuel.

While you have the air pipe disassembled from the throttle body and air box, checking/repairing/replacing it, take off the mass air flow sensor right after the air box, its held on by two screws - purchase some MAFS cleaner (don't use anything else) and spray it inside where those wires and heating element is located. Let it drain down when spraying into it. Do it about 5-7 times in short bursts, with a few seconds in between. Allow it to dry for a few minutes, and reinstall when you are finished with your air pipe. That has fixed my lean code with restricted performance message totally.

Now, misfiring may be something you need to explore, when a coil goes, most of the time it is from oil/water getting into the plug wells. Its easy to check yourself, just find the document in the FAQ that deals with spark plug change, and Rev Sam just did a video (aren't you lucky?) where you can pull your coil and check the wells for substances (before pulling the plug) If you do, get that fixed...perhaps a new valve cover gasket set, and then clean the coil and run it. If the coil is too far gone, gonna have to replace.

Neighboring coils can be affected by one bad one, so don't wait too long.

Running a car with recurring misfires too long can also cause irreversible damage to your catalytic converters, and that's a repair bill nobody wants to see...$1000s.

Good luck.

 

BTW, your P0455 evap emission issue will cause you to fail inspection (at least here in TX). Don't worry about that right now, it won't affect your car's performance or affect the restricted performance/misfires you are facing.

After you get the major codes dealt with, you can find what most of us have done to remedy that code by doing a search for P0455. Its a small repair parts replacement, most do themselves. Dealer did mine however, as I didn't know where to look at the time.

 

Thanks Matt,

The restricted perfromance light would clear at cruising speed and seemed to pop back on on deceleration. Also, do you think the low oil level could have caused a condition that triggered the lean codes? It was 4 qts low.

Tom

 

Grats on the Jag! Hope you get your problems sorted out.

 

4 quarts low is WAY low. That's two quarts below the end of the dipstick. I don't want to sound condescending here, but are you sure that you fully inserted the dipstick? Even when I do an oil change with filter I can only get about 7 quarts in it. That means you were only running on three quarts! I'd think that the engine would start making noises at that point.

By the way, here's the video that h20boy mentioned:

http://www.youtube.com/watch?v=4aBR6ggziw4

 

I did check out your youtube page, very helpful! After clearing the codes and driving around for approx 100 miles the RP and engine icon came back on.

I'm going to get it back on a code reader and see what's going on. I definiteily smell an oil leak but can't find it on visual inspection.

As for the 4 qts low...it was below the dipstick when I checked (after driving from BWI to LI NY). It might have been a little less than 4 qts but at least 3.

Any validity to the theory that low oil level could trigger a low oil pressure sensor (in the head) and cause the lean codes?

Thanks!

Tom

 

I don't know if an oil pressure sensor could cause the lean codes, but if you accidentally over-filled the crankcase with oil then I think that extra oil would have to go somewhere, and that could cause the burning oil smell. Maybe it's just being blown out the exhaust pipe.

Sorry... I seem to be stuck on that whole "four quarts!!!" thing.

 

Haha! No, definitely didn't overfill. And smelled the oil prior to adding the, let's call it 3-4, quarts. I will keep you posted though. Thanks!

 

Its gotta be coming out of those valve covers then...if you get misfires on your new code reader, its time to get new gaskets. Driver side, very farthest back is the most common spot, IIRC.

Low oil will not cause a lean condition to occur.

And tom, you never mentioned if you even took your air pipe off to take a look. May I ask why?

Please take this advice from a dedicated, longtime owner, wishing really hard that the light will not come back on in this case, is ill-advised...you're just daring fate to deal you more problems, potentially more damage, and raising repair costs. You've got lean mixture, coupled with misfires.

If you're cats become blocked due to the excessive unburnt fuel entering the exhaust, it will not even run anymore, and then you won't have to worry about the lean condition.

 

Oil pressure is not depended on the oil level, it either there, or not. If oil light never popped on, then you got lucky and oil intake was never dry.
congrats on that and shame on that butthole who sold you car with no oil.

Also, I easily get 8 qts in my motor and it is ~1mm. above top level on dippity stick.

I think you are in for vaccuum leak, or clogged breather on the left side.
Big looking problems, always result in small findings.

 

Thanks H2O - I'm going to get the codes reread today (I had them reset after the initial reading). I'll see what pops up (the RP and engine icon did come back on after about 100 miles). I checked the air pipe at the TB connection and it was tight. Did a visual on the rest of it (focused on the corrugated part) and it looked OK. Definitely smell oil. Looking at the coil covers it's obvious someone's been working on it. Several of the bolts are loose/missing. The PO said it recently passed MD emmissions testing. I'll repost when I get new info. Thanks!

 

see if you have any oil in your air pipe or inside the throttle body too

 

H20 -

I have some issues. my mechanic smoke tested it and there is a hairline crack in the intake manifold and, as he was describing it, a seal in the coupling under the TB that is "not serviceable" per Jaguar.

lean codes only came back on one bank. the RP or misfire codes have not reappeared. could the lean problem be casuing the misfire condition?

as for the oil leak...there are minor leaks from the gaskets but nothing serious. there was oil in the pipe. what does that indicate?

the PO is willinng to split the cost of the intake manifold issue with me. he also said the motor never used excessive amounts of oil. so this is still a mystery.

there is also a rebuilder seal on the motor so i guess it's either been rebuilt or replaced at some point. car has 94K.

so im headed towards an r&r on the intake manifold and will attempt a repair on the coupling seal problem. new gaskets and some other misc stuff.

thoughts/recommendations?

Thanks,

Tom

 

Yes, lean conditions can cause misfiring if its bad enough, its basically reducing the manifold pressure from its optimum range. Ever take the oil cap off of the engine while its running? That is what a large air leak can do to the combustion process. On the other hand, it only takes a little bit of oil to get into the plug wells to wreak mahem on the ignition coil. Change those gaskets now too, while you're in there, as they won't get any better over time.

Oil in your air pipe and throttle body is a good indication that your part load breather is clogged, as Mish_Mish wisely mentioned in his above post . There is a detailed DIY PDF in the FAQ thread for the xk8-xkr model, its bundled together with the throttle body cleaning and MAFS cleaning, you should do all three. It is under the Engine category.

With an intake leak, and a throttle body seal issue, that would create plenty of opportunities to create your lean condition. When you have air leaks, you'll find that it could be either one bank, the other, or both...it just depends on the timing upon which it occurs, if that bank (or banks) had a repetitive lean condition three times in a row, then it'll throw the code. Don't think one side or the other is being targeted, its just happens to be that one bank got pitched three strikes in a row, first.

When you get those corrected, do a hard reset, and make the car learn immediately the new fuel trim data...otherwise, you'll notice some erratic RPMs until the long term fuel trims balance with the short term.

 

Thanks H20! On the plus side it's a sweet looking XK8, it's the metallic black with a saddle interior, and the engine is strong and the trans smooth. All the accessories work fine too. I'll post some pics when I get it straightened out. I've owned a 3 XJS', a couple of XJ8's and an XType. This is my first XK8. I really love it despite the rocky start.

Tom