It will be on the car's left on the rear of the transmission

This connector can get some oil from the rear edge of the valve cover gasket ( hidden ) , there is a seal section that can fall out of place

There is a valve cover seal torque pattern and value

If replacing the hardened / aged seal there are source recommendations as there are some inferior

 

03.1-08 (jagrepair.com)

 

Good evening all, another update. I have changed the CKPS, the car seemed to start a bit better than before, but still has a low and rough idle, though perhaps not as rough as before? She's still misfiring on one cylinder, no.4 from the front.

I tested this by disconnecting the coils whilst the engine was running. All but no. 4 had an effect on the idle, so that's a clear sign. I swapped coils 3 and 4, the problem cylinder did not change. So the coils appear to be functioning. Then I swapped the spark plugs from 3 and 4, and again the problem remained in cylinder 4. At this point I exclaimed 'bugger', as instructed by the Jag manual, dismayed that my issue does not appear to be as simple as the plugs. Plugs will be changed, however, as they were quite black and not the type everyone recommends.

So, cylinder 4 is playing up regardless of spark and coil. Could be injectors, could be power supply to the coil, could be compression? I will test cylinder 4 for spark next time I get a chance by removing the plug and seeing if it sparks against the engine block, thereby removing power supply to the coil from the list of issues. Injector function can be tested by, I think, removing the plug and seeing if a petrol smell emits after cranking? Or the slightly more complicated method of swapping injectors between cylinders. Finally, the dreaded compression. If all of the above fails, I'll buy a compression tester. Hopefully that isn't the issue however.

If these symptoms point towards a particular problem, please let me know. I think I have the potential issues narrowed down and will continue my diagnosis with more tests, probably on Sunday. Fingers crossed its just the injector, everything else sounds a bit too complicated for me!

 

On the # 4 coil plug there will be 12 volts present at all times on the White / Pink wire , the other wire is the ground provided as timed by the ECU to open the injector

The same with the fuel injector , different wire colors

If you pull the injector out by pulling the fuel rail there is a precaution

Have you used the Chevron brand fuel injector cleaner ?

ECU connector check for corrosion



Your # 4 coil timed ground is Black 5

Your # 4 injector timed ground is Black 13

Look for 2 pinching tabs as the socket as 1 tab can be missing , there are spare sockets

 

Hi Parker! Yet more invaluable information, thank you kindly. I think I'll change the spark plugs, add a healthy dose of injector cleaner and then take her out for a blast, try to get some fuel flowing through the system to encourage cylinder 4 back to life. I will test the voltage of both the coil and injectors too. I've already ordered a coil but that can just sit in the boot for emergencies if these are all functioning fine.

The precaution you refer to regarding injector removal; is this to depressurise and dry up the fuel system by removing the relay and filler cap and running the car until it stalls, then to take care not to bend the fuel rail when removing it? Those were the main concerns I've seen in my research. I've done a lot of fuel related work in the past on a 1992 one litre Fiat Panda I had, so i've had enough fuel related dramas to last me for now. That was a wonderfully frustrating car to try and fix... Anyway, is there another precaution to follow?

I've definitely made some progress narrowing it down, so I'm satisfied with tonight's efforts. Hopefully, but probably not, the new spark plugs make a difference. I suspect the issue lies with the injector however.

 

The rail can be levered up with a long wood stick where you have more control to not over shoot when they break loose from the injector o - rings bending the fuel rail

There are basket filters in each injector , both basket filters and Verton ( ? ) O - rings on E - bay

Node light on coil / injector wires ?

The fuel pressur should be 43 PSI going up the 47 on throttle up

Main fuel filter change

Italian tune up ?

 

Good morning, just a quick bit of tinkering this morning before I had to go out. I checked coil number 4 for 12V, that was present. Then I got a nice blue spark to jump from the coil to some metal, so that’s good too. Then I removed the plug from cylinder 4, cranked it briefly, and some petrol vapour did come out.

Only thing I forgot to test was spark from the spark plug attached to the coil, that’ll be tested tomorrow.

Today’s diagnosis seems to have confirmed we have fuel and spark. So either the compression’s gone, or it’s sparking at the wrong time, or the spark isn’t getting from coil to plug. Or maybe the injector is dirty and delivering an odd spray? I think I’ll drop in some new plugs and injector cleaner tomorrow then try the Italian tune up. I’ll order a compression tester as well, I hope it’s not that.

It still wasn’t too happy to start either, so the initial issue is still present. It was very cold this morning though. Low, rough idle, nearly stalling without throttle input. I’ll fix the misfire first, then see if that’s still an issue.

 

A jumper wire ( medium gauge ) on the fuel pump relay socket has a chance of improving fuel pressure if lacking

This will be socket 3 ( battery socket ) to 5



Use blade type connectors


Not a bad thing to keep in the trunk on the road , the fuel pump enable of the one aspect of the few in how the single CKPS signal is used, is common

Jumpering the relay will keep the fuel pump running at all times with the keys in your pocket

Someone pinched off the rubber return line hose to see that the fuel pressure regulator was too low

If you can hear a gurgle at the FPR or tank then the pump is putting out a fuel pressure above the FPR and is naturally returning back to the tank

There are some wire splices in the wire bundles on top that if compromised will limit the power to run a coil / injector

 

The precaution on the fuel rail removal is to not have the lever stick end on the edge of the valve cover , brittle magnesium.

 

The fuel injector for the normally aspirated are different ( color marking band ) then the supercharged

 

Have we checked the throttle butterfly? A common gunked up butterfly can be the cause of all of this! To clean it, it’s best done by removing it from the manifold. Don’t forget to be ready to plug the coolant line that goes in and out from underneath. A golf tee works great here! (You’ll need two)

After that it’s just 4 10mm bolts holding it in place. There is no gasket between the two metal surfaces of the throttle body and intake manifold.

The car should idle at 700-720rpm in park, warm. 580rpm in drive.

If you have an OBD2 reader, the butterfly should be at 12.9% when at idle. (At least it is on the XJS with the same engine). The butterfly should have a gap of .002” when closed.

 

The 11 -13 % is at butterfly idle stop

The not 0 is accounting for the IAC being slightly open

The mount bolts on the IAC can snap off by locktite , 5.5 mm

There shound be a gasket on the IAC

There is the suggestion from Vee to slightly twist the pins / blades on the IAC to make better connection

Might as well clean the EGR valve and EGR valve temp sensor next to the valve

Your EGR_ Error ( ELM - 327 parameter ID or PID label ) should be at 0 % in all engine ranges but is not perfect , it has a position sensor in it and should read 0.7 volts DC at idle on the Red / Pink color wire , the connector must stay on

Your EGR should be in the closed position at idle

Hold off before sourcing a EGR valve

 

Hello again. I’ve taken the fuel rail off this morning. I do have 12V to the problem cylinder, both to the coil and the injector. I also swapped injectors from cylinder 4 to cylinder 2. Unfortunately, the problem remains in cylinder 4. What’s next? I think I’ve done as much diagnosing as I can.

 

I’ve ordered a compression tester, should arrive tomorrow. In the meantime I tried the old fashioned compression test of putting your hand over the spark plug hole, it certainly felt like a strong squeeze. Looking down into the cylinder, the piston was black and dirty, and the plug too. The exhaust is chucking out black chunks. Perhaps a stuck valve? Italian tuneup may help, not really sure how you clean out a cylinder without stripping the engine down to the block.

 

ECU connector check ?

 

I'll have a look at the ECU connectors you mentioned in an earlier post tomorrow, I'm exhausted today and it's getting dark. Would a failure in either of those two connectors, injector and spark for cylinder 4, cause the misfire? Both spark and injector on cylinder 4 are functioning, so could they just be triggering at the wrong moment? Thanks for your help. Tomorrow I should receive new plugs, a compression tester, and a spare coil, so I can try out a combination of those to see if I have any luck. Hopefully it's not time for a new engine...

 

Odds are the timing is correct ( if the pairs or groups of cylender are ) and just a connection that is underperforming the component

The ECU connector sockets should have 2 pinching tabs as a socket , there are spare sockets

 

See post # 26 from Don B

P0300 and P1313. Here we go - Page 2 - Jaguar Forums - Jaguar Enthusiasts Forum

 

Thanks, so do I move the connectors to one of the spare sockets and see what happens?

 

No

The spares are in a not occupied / used socket position with no wire attached