Noooo! Don't put the cam covers back before you at least replace those secondaries.

 

Well, it's back together. I couldn't get the cover to seal up 100%. Perhaps new seals would do it but I don't see how the small cover leak could affect the the engine performance. I installed a new fuel filter today as well. It is running noticeably better with 3 after maf leaks sealed up but still misfires if snapped to wot. The spark plugs are nkg brk5E. Not sure if those are correct and will probably upgrade them. They looked OK but were gapped pretty wide like .060 so I knocked them back to .045. Any suggestions for plugs appreciated.

Also to note, the fuel trims have stabled out considerably. I cleared the codes so I'll let the drive cycles run up and see how things look in a few days.

 

 

I've ordered new metal chain tensioners. Is it true that this will happen to every engine if the tensioners aren't upgraded?
​​​​I got very familiarized with the engine today working on the passenger side only. Once I have new cover seals and spark plugs I'll do it all at once. May do the coil packs just for good measure.

 

I've no doubt there are many x100 and x308 cars around that still have the old plastic tensioners, but it's a lottery. I also appreciate it's easy to sit in a comfortable armchair and recommend preventative surgery...

It depends on how deep you want to dive: I would do both primaries and secondaries, although it's the latter that are the engine-killers. Do a search on 'zip-tie method' for the easy route to address them.

One tip I was given re a good seal on the cam covers is to replace the isolator washers (# NCA2575CA) on the cover bolts along with the spark plug boss & cover seals.

 

OK, full timing chain kit, iridium plugs, coil packs and cover seal kit on the way. I don't mind freshening up the engine a bit since I feel the car was a good deal for the condition and milage.
Not sure this will cure the stumble but shouldn't hurt anyway.

 

If it's going to be a keeper, I think you're doing the right thing.

Spending your money again, but I'd also recommend going a bit further and replacing the valley hoses and plastic plumbing around the thermostat 'while you're in there'.

It's a lovely looking car

 

Seems that's probably a good idea. Is there somewhere that sells all the hoses as a kit?

 

Under the time previous owner of my 2002 XKR there was a failure of the tensioners at about 115,500 miles. It cost him $5,000 to hafe it fixed, which included the upgraded coolant pump.

That is just one demonstration of the necessity to get the work done before a failure happens. It’s much much cheaper before the failure to address the issue.

Although it’s been posted here that the 2002’s have the latest tensions installed at the factory, using my car as an example, I’m thinking that depends on the engine build date.

Z

 

my idle is normally higher for the first few seconds after starting. Then it goes down 640-650 rpm and stays there.

I think an idle of 750 rpm is too high for an engine that’s warmed up.

my plugs (NGK laser iridium IFR5N-10) are gapped at 1.0 mm (0.039”).

 

I had this problem with a 97 XK8. It was solved when I discovered a very bad leak in the throttle body gasket...about 1/2" of the gasket was missing.

New gasket, problem gone for 6 months now.

 

And you will need a new crank seal, crank bolt, vanos shaft seals, vanos solenoid seals, oil pan seal, cooling cross pipe seals...

 

Not sure about the kit, but I posted a list here:
https://www.jaguarforums.com/forum/x...9/#post2466950

of the usual suspects. Ignore NCA3976AD:- you need NNE3976CA for the AJ27 & they're not interchangeable.
Ask me how I know...

 

Awesome thanks!

 

Just to update and close this, a boneyard maf sensor from an '07 Subaru Outback totally fixed this. I guess the old sensor must have been sluggish or something as it appeared to be operating correctly on the scan tool. Either way, car runs flawlessly now and I'm even happier than I was already with this Jaguar.