I recently just bought a 2000 Jaguar xj8 as my first car. I’ve replaced the three ignition coils that were bad, it took it out of limp mode for a bit but it got put back into it. I searched common problems and saw that the timing chain tensioners were a problem. I heard some ticking/clicking from the front of the engine. Just wondering how I would diagnose them and fix them? Thanks.

 

Note aside: When I had "restricted performance" mode (limp mode), the culprit where the knock sensors.
An OBDII reader might give you a better idea of what your issue is.

There are 2 sets of timing chain tensioner - the upper ones and 2 more right in the middle.
It is possible to look at the upper ones by "just" removing the cam covers.

When you see that those tensioners are the old ones (they are made out of some brown bakelite (or a plastic similar to bakelite)), then you have the old ones and it is a sign that you should a swap, as I did it:

I changed my timing chains, tensioners and guides:

https://www.jaguarforums.com/forum/x...e-swap-266724/

 

If you don't have the maintenance history on the car showing that they've been replaced, then you absolutely MUST check the secondary tensioners before you drive another mile because they are a like a bottle of nitroglycerin at this age, just waiting for a good sized bump to destroy your engine. Go ahead and get a valve cover gasket set on order today along with a seal for the VVT solenoid. The easiest thing to do is to remove the passenger side (US) valve cover (driver side has a little more stuff in the way). If the tensioner housing is made of aluminum, then the bomb has already been defused. Most likely if they did one side, then they did both. You can put the valve cover back with the new gasket and seal and relax. If you see what Peter described above, then you need to order a set of the secondary timing chain tensioners and start searching this forum for instructions how to replace them. Get that done next weekend or sooner.

Just a side note, the primary tensioners (on the long chains) are made of the same kind of plastic and can crack too but are not nearly as likely to fail catastrophically as they don't see anywhere near the torsional stresses that the secondary tensioners do. If the secondaries are nitroglycerin, then the primaries are only like tannerite. If you have the time (and it takes some special tools - which you can order on Amazon), it'd really be best to replace those too along with the long plastic chain guides as a preventative measure, but whether you do or not kind of depends on the value of the car, how much risk you are comfortable with and how well attuned you are to the changes in sounds and sensations that your car will exhibit as it ages.

 

Thanks for telling me about this, I’ll go ahead and check those today, I checked with an obd reader and got a P0327. I’ve removed the old and have ordered a new one, I will check and order the other parts you have mentioned. I’m pretty comfortable with messing with it as I’m not driving much. Thanks again for telling me these things as I wouldn’t have a clue without.

 

When you say seal do you mean the gasket?

 

P0327 KS sense circuit out of range (low
voltage) A bank

Start engine; run > 5 seconds

When DTC is logged (first trip), ECM:
– Sets ignition retard to maximum
– Limits engine speed to 3000 rpm

Possible Causes
Poor sensor contact with the cylinder
block
KS to ECM sense circuit short circuit to
ground
KS failure

 

On the XJ8, there's a round lip seal pressed into the top of the valve cover that slips over the vvt solenoid. Normally does not come included with the valve cover gasket set and has to be ordered separately. Just wanted to you know since it would be frustrating to be putting it back together, almost ready to drive and realize that you have to order something else and wait.

 

looks like this?