I have just strated the XJR up which has been stood for some time, a new battery has been fitted and the following codes have been reported from my OBD2 reader
Can you point me in the right direction to look for these faaults, could they all be related to one fault, air leak? or something

Short Term Fuel Trim Bank 1 - 4.69% Lean
Short Term Fuel Trim Bank 2 - 0.00%
Long Term Fuel Trim Bank 1 - 4.69% Rich
Long Term Fuel Trim Bank 2 - 14.84% Rich

Fuel System 1 Status - Open Loop Control due to System Fault
Fuel System 2 Status - Open Loop Control due to System Fault

P0300 - Random/Multiple cylinder misfire Detected
P1316 - Fault definition not available or manufacturer specific
P0205 - Injector circuit malfunction - Cylinder 5

 

You need to look in to the P0205 code first. Use a mechanics stethoscope and see if it is clicking like the others. If it isn't make sure it is plugged in properly.

 

After doing some general investigation I have found 5 rocker cover bolts missing which could cause a significant vacuum leak, I have ordered new bolts which should be delivered next week, I also found a bend/fracture in the oil dipstick pipe, this also had a hole in it, so I will be making a smoke tester once I have the new parts to see if there is any more air leaks.

I presume the clicking will be the injector firing? i'll take a look at that once the other jobs are done

 

Sounds like you're making good progress - and yes clicking could well be injectors.

 

Yes, the clicking would be the sound of the solenoid in the injector. It is easy to hear with a cheap mechanics stethoscope. But, based on your last post you will probably find the injector is fine but still it is a easy thing to check and eliminate.

I have been very successful using carb cleaner to find vacuum leaks. Check the seal of the injector into the intake. I had this problem on mine once because I didn't get a couple of the injectors seated properly into the intake. I sprayed carb cleaner at the base of the injector and could hear the sound of the engine slightly change.

 

Don't rely on hearing the engine note change - it may not. Use the STFTs.

 

Well today I have received most of the parts I needed to get the job done

I had an almighty pain replacing the dipstick, I ended up draining the oil and poking a wire up through the sump and threading the pip around that, I needed to change the oil and filter so I had everything here ready, But Job done.

The remaining rocker cover bolts have been replaced and the Misfire on cylinder 5 was traced to a chewed cable (Rats!!!), this was repaired and that fault has been cleared

So the original faults were cleared and now I have P0308 - Cylinder 8 Misfire and P1316
Short Term Fuel Trim Bank 1 - 0.78% Lean
Short Term Fuel Trim Bank 2 - 0.78% Lean
Long Term Fuel Trim Bank 1 - 4.69% Lean
Long Term Fuel Trim Bank 2 - 2.34% Rich

Whilst I had the car on jacks and the wheel off I replaced all the ABS sensors on the wheels, this was because I have restricted performance due to Traction Control Fail and Stability Control Fail, I still have this problem unfortunatly

 

Changing the wheel sensors is more expensive than having a shop with the proper software read the codes, and the sensors do not often fail. It could even be the brake switch.

 

The sensors were £7.50 each, the two front ones had to be drilled out they were not in the best of shapes, its a small price to pay, as the car is on a SORN I cant just pop it down to a garage to let them look at it

I have checked with another OBD11 reader and the faults that show are P1637 and P1720

P1637 = CAN Link ECM/ABSCM Circuit/Network Malfunction
P1720 = Vehicle Speed (Meter) Circuit

What brake switch are you referring to??

 

The brake switch is on the pedal, the codes are C prefix and you can't read them with a generic tool. I hope your new sensors work, but I would not trust them.

 

So far the P1720 has cleared and was probably left over from the old battery. the P1637 was from a cheap hand held OBD reader, so no codes left as such.

I have tested the sensors back to the controller and all is fine with them, the problem I found was the connection through the ignition switch wasn't good, I wasn't getting a good clean ground from the ignition to the ABS unit, I have ordered a new ignition switch to see if that will solve the issue

 

​​​​​​can you share the link of the bolt, I ammhaving the similar issue

 

Do you mean the position of the bolts or where I got them from, I'm in the UK so the supplier wouldn't be much use to you

https://www.ebay.co.uk/itm/CAMSHAFT-...53.m2749.l2649

This is the bolt location on one side only, I found them missing on the other bank but the locations are the same