Hello Guys,

Been a happy owner of X-Type for last 12 years and 3 weeks ago I have treated myself to XJ Supersport. Unfortunately today it has gone into limp mode and EML came on. Engine runs really rough. Reading codes and getting P0304 and P0316, which both relate to cylinder 4 misfire. I have deleted the codes and EML has gone, but engine still runs rough and not right. I did see somewhere that after multiple misfire the ECU switches fuel supply to the equivalent cylinder, hence engine still runs rough, but will it delete itself and fuel will be supplied again to the injector or does it need plugging in to the Jag software? Do I need to book it in to Jaguar for investigation or are there any other bits I could look at myself before spending money? Any help will be much appreciated.

 

Are you able to do any repairs yourself. It seems you will need at least one ignition coil and sparkplug for sure. Depending on the age of the coils if known i would be looking at replacing all spark plugs for sure and maybe all coils. Comes down to same old decision of money willing to spend. A do it yourself parts price with oem coils should be about 500 dollars or less. You do not have to use jaguar branded coils. You can use oem manufacturer coils like denso or bosch. Dont know what yours has. I recently replaced all 8 coils and plugs myself on my 06 s type r for 450 dollars in parts using oem denso parts from rockauto. Different vehicle but same principle. It would not hurt to have a full vehicle scan done if the car has unknown history to you

 

Deleting codes do not fix anything. You just wiped the notes of the issue away.
Yes, when ECM detects that raw fuel passing O2 sensor, it turn fuel injection off from that cylinder for protection of CAT:s.
It will try return normal condition on every start, but if failure persists it keep protection CAT:s.
Misfires can be caused by many things, these are most common: Failed spark plug, failed ignition coil or exsample failed fuel injector.
I would first take the spark plug out and change it to new one. (when thay have been changed?) If that not help i would swap Cyl 4 ignition coil with Cyl 1 ignition coil and check if the fail move to the Cyl 1. If yes, then we have found the issue. If fail still stay on Cyl 4, i would expect that the injector is playing up. Before removing fuel injector i would make compression test for the Cyl 4 in case it have lost compression by piston rings of leaking valve. (Bang will need 4 things: Air, Fuel, Compression and Spark)

 

Thanks for your reply. Easy said - having 5.0 litre superchrged means there is no spare space under the bonnet and I don't even know how to get to spark plugs, coils etc. Used to do the lot on X-type, but this car is different story

 

i understand your dilemma as i was speaking from 4.2 liter knowledge. I have watched videos on the 5 liter supercharger removal out of curiosity but have no idea how to advise. Sorry. Now i wonder do the coils still go thru the cam covers. I did take notice that the charger intercoolers take up a lot of side space over the engine. At least a vehicle scan should be simple with the right equipment. Someone with 5 liter experience will chime in i am sure

 

Hello again, so today I have managed to swap coil from cylinder 2 with coil from cylinder 4. The fault code stayed the same So coil is ok. I did shine the torch to see the spark plugs and its all dry, but noticed black dot on the top of the spark plug in cylinder 4 (not sure if that's the issue), but it looks like real pain to get this spark plug out due to obstractions. My next step will be taking it to dealers I think, as I cannot be bothered to go any further on my own. Can you guys confirm if the cylinder 4 is second one from the front on the RHS? Thanks for your comments, I'm really frustrated as enjoyed driving this car but it lasted only 3 weeks...

 

left hand bank (steering wheel side)

 

So I have tested the wrong cylinder? So are they numbered 1,2,3,4 on the left bank, which means the cylinder 4 is last one?

 

Cylinder numbering scheme as viewed from the driving position:

Bank A (RH side of vehicle) - 1, 3, 5, 7

Bank B (LH side of vehicle) - 2, 4, 6, 8

Thus DTC P0304 is the second cylinder from the front on Bank B (LH side of vehicle)

Misfire(s) with the AJ133/AJ126 are usually caused by sticking or stuck fuel injector(s). If an injector is sticking, raw fuel enters the sump and can cause bearing damage if the vehicle is continually driven. Under no circumstances is the vehicle to be driven under conditions that cause the MIL to flash as catalyst damage is occurring.

 

Hello guys, so the update to my post. I had the car connected to the OBD reader in the garage and whilst it running it throws cylinder misfire errors on all cylinders. I decided I will replace the timing chains, guides and tensioners. At the moment my car is stripped down and I have managed to fit new chains, guides and tensioners. Old chains were flapping around as I had tapping/knocking noise every time I have started the car warm. Tensioners were absolutely knackered and they were doing nothing, I could move the chains as I wanted. Question to you guys is if I fitted new chains properly. So I have removed knock sensor and fitted special tool, I have removed starter motor and fitted special tool, the crankshaft key way is at 6 o'clock, Camlocks are fitted to the back of each bank. I put the chains on variators so the notches match marks on the chains and when it comes to the mark on the guide it almost looks like mark on the chain is one tooth before the notch on the guide. Is there anything I'm doing wrong? Same on left and right chain. Can it be something else wrong there, as far as I'm aware I have followed the procedure. I'm just wondering if something was wrong at the first place causing all misfire codes or was that just caused by loose chains and bad tensioners. Can you guys give some advice please? The chains sit nice and tight now, but I'm just a bit curious about that guide mark missing the chain mark. Thanks.

 

The marks on the chains only line-up with the marks on the cam sprockets once every "whole bunch" of rotations.
I found this out the other day when I was checking it out before taking it apart.
They lined-up like one or two rotations past where it was last shut off, but after I rotated the engine (by crankshaft) they were off.
So I rotated again. And again... And then a whole bunch of times, and they never aligned in the same place.
Until after a lot of rotations, (I figure maybe equal to the number of teeth on the sprockets?) and I was about to give up, they all lined-up again.
The marks are only there for the initial set-up.
And since the number of teeth on the cam sprockets don't = the number of teeth on the crank sprocket, and then the length of the chain... they don't align each time.
Apparently there is timing with the HPFP cam also.
If the high pressure fuel pumps are out of time, that could cause it to run rough.
I don't know the details of that, but I am leaving the crank right where it was with the cam chain marks lined-up to the sprocket marks.
And my best guess is that the HPFP cam will be right where it was - I'm not disturbing the chain/sprockets between the crank sprocket and the HPFP cam sprocket.
And I'm also taking notes/pic of where the timing mark is on that chain, in case I do need to rotate the crank before refitting the cam chains.