User Addicted2Boost suggested that the firing order posted above may not be correct for my model year, and that all the misfiring cylinders could be on one bank and that the timing could be by a tooth on one set of cams. I did a bit of googleing for XJ8(R) firing order and found this, it was for an XK8, but they did use the same motors.

 

Just to eliminate one possibility that could be a reason for engine knocking. I note that you have replaced the heads and that, one of the posts stated that "Jag V8 engine XK8, XKR, XJ8, XJR and S-Type V8 heads will all work". This is information is missing an important detail: in order to use heads from NA engines XK8, XJ8 and S-Type on a Supercharged engine, you must plug the VVT oil holes at the front of the heads:

Were the heads you put on from an NA or SC engine? If from an NA engine, and you did not plug the oil holes, you will have very low oil pressure.

 

Heads were from an SC car

 

Given that your misfires are on the left bank, I suspect mistiming.

 

I have a long shot possibility, it is a mistake I made. When you reinstalled the cams are you sure you did not get the cams from your old heads mixed up. The cams for each bank are different. They are 180° different. So if you put in 2 right side cans in your left bank will be 180° out of time. When I did my rebuild I got them mixed up with another set. Check the number on the cams. If they are the same part # your bad bank has the wrong cam.

Good luck,

 

I don't think that could have happened. The cams from the old heads were bolted into the heads with the cam journals and we're never removed.
I'll double-check when I pull the cam covers though.

 

If your car is prior to MY 2002.5, then the left numbering on your picture applies. For easier reference, I have made a simpler diagram for it:

 

I read my old post about the wrong cams. I had zero compression on the bank with the wrong cam so I don't think that is your problem. It still doesn't hurt to check.

My suggestion would be to remove the cps and install the locking tool in the flywheel. Then go up top and see if your cams are flat. There is a chance you my of had a little slack in the chains and tha will throw your timing off. Doesn't hurt to check to eliminate the cam timing.

 

So I pulled the valve covers and rotated the crank and tried to see the timing mark on the flywheel. I was not able to see this mark anywhere on the flywheel. I made a mark on the flywheel and turned the crank around looking for the flywheel, when I saw the grease pencil mark again I knew I'd made a full rotation. I remember not being able to find the timing mark last time too , instead I removed the crank position sensor and rotated the crank until I could see the hole for the crank locking pin and then slowly rotated until the locking pin could slide into place. With the locking pin in place I climbed out from under the car to look at the cams, both flat parts of the cams were facing up and the cam locking tools easily slide over them.

So unless there are multiple holes for the crank locking pin to go into, I don't see how the timing could be off.

 

If the misfire codes (P030x) do not move as you swap the ignition coils, you should check the injectors. It is not uncommon that injectors get stuck if left sitting for very long with some fuel still in them. As the fuel evaporates, it leaves gummy residue which can block the injector pintle in the closed position.

Whilst your cam covers are off, disconnect the injectors and test them one by one by applying 12V directly to their pins and listening for clear/sharp clicks. If you don't hear any click but just have some sparking on connection of the 12V to the pins, the injector is stuck. Sometimes, you can unstick such injector by repeatedly applying 12V to it.

 

I hope that's not the case. I can't get to the injectors without removing the supercharger the charge air coolers and the intake elbow and throttle body.

Also could it be the injectors. Before taking everything apart I did a compression test. I removed the fuse for fuel injection to do this so wouldn't that have eliminated any fuel in the injectors???

Also I'd be surprised if all the I injectors on one side and only one side got stuck. Bit too much of a coincidence.

 

Since you removed the fuse for the injectors, they were not operated during your compression test (all stayed closed) so the fuel remained in them.

 

I can only rec up to 3k rpm due to the transmission fault putting it in limp mode but as it revs up the knocking smooths out. Could be an indication it's not injectors stuck closed.

 

I had a thought today, I would find it very coincidental that all four injectors all on the same bank would get stuck, but what if there was something clogging the fuel rail? It would explain why it was only on one bank of the engine and why it is all four injectors on that side. I borrowed a fuel pressure test kit from Auto Zone on my way home from work today, I'm going to give it a test when I get the valve covers back on.

 

Here is video of checking the timing, you can see the cam locking tools can slide right over the flat part of the cam indicating the cams are in the correct position:



Also here is pictures of the crank locking tool. I was tough to get a good angle of this with the phone but you can see that the locking tool is slotted into the hole in the flywheel. I wasn't able to find the mark on the flywheel so I had to line up the crank by looking for this hole for the locking tool. The only way I could see the timing being off is if this is in the wrong place but I don't believe there is more than one hole the locking tool fit into.

 

The fuel pressure tester may not give you any info regarding any blockage/debris in one of the fuel rails but it is still good to check your fuel pressure. If there was some debris in the rail, some of it would have been pushed back into the tank pass the fuel pressure regulator or stuck inside the regulator (in which case you would have somewhat higher fuel pressure.

Some of the debris would have been pushed towards the injectors and could have clogged their inlet fine mesh filters. To check this, you would have to remove the rails and then disconnect the injectors.

In Malaysia, I cannot leave outside anything with small orifices exposed (like fuel pipes etc.) as, very soon, those mud carrying wasps would plug them solid. Once I tried to blow through a small pipe plugged by a wasp with my compressor at 7 Bar but it could not blow the mud/nest out. The only way was using a wire to poke through.

 

I'm going to try to test the injectors on the car, I think I can just about get the connectors off in what little gap there is between the intake manifold and the charge air coolers. God only knows how I'll get them back on without removing everything. Anyway could you elaborate on the testing procedure? What do I just for a 12V source? Is a car battery fine or is that too much amps?

 

The car battery should be fine for checking the injectors, but do NOT connect the power source long. Dont connect power + ground and leave it on an injector, it could burn it up, rotate on, off, on, off.

Thats what ive always been told and always done on my cars. Ive never dealt with a clogged injector, but running carb cleaner through the injector has worked well over on the XJS forum for those reviving long sitting cars.

 

What's this procedure for cleaning with carb cleaner? Can this be done on the vehicle? If so that sounds a lot easier than potentially removing everything to get to these injectors.

 

The procedure I have seen (and sorta followed for one of my cars) was to take the fuel rail + injectors off the car, fill the rail/injector intake with carb cleaner, then run the injectors so that the carb cleaner either A shoots through the injector pintle or B begins to degum the injector from the inside out until A happens.
Unfortunately, injectors still have to come out.

Alternatively to taking the rail, you can take the individual injectors and use a hose on the inlet and fill the hose rather than fill the rail.