2005 XK8 4.2 Cylinder 6 Intermittent Misfire
#1
2005 XK8 4.2 Cylinder 6 Intermittent Misfire
Hi,
Firstly I have to admit to being a real novice with engines of any type but am loving learning about this fantastic car.
So far I've fitted a new quad "straight through" Adamesh exhaust...new mesh grill, replaced the thermostat and water pump, cleaned all of the wheel sensors, upgraded and fitted 20" BBS Persius Wheels, polished it LOTS and simply put have a stunning looking Pacific Blue with Ivory Leather interior XK8 Convertible....what more could a middle aged man want.....mid life crisis I hear you saying!!
However, over the past 6 months I've been plagued by an intemittent "Restricted Performance" message on start up.
Initially it occurred shortly after a service and on removal of the coil and plug I notice a little oil. As this plug is below the oil filler, I assumed that there had been a little spilage during the service!
Having cleaned the small residue of oil I replaced the plug and coil pack and initially all seemed fine and I thought that had solved the problem.
Alas, the next time I took her out for a spin, the same happened again.
At this point I should mention that she only comes out of the garage on good days and only covers about 3k miles pa.
I've now swapped the coils around and replaced the plugs with NGK IFR5N10, but once again the problem came back at the weekend.
I have just put a bottle of FORTE Advanced Petrol Treatment in the tank and am waiting to see if it makes any difference....could it just be a clogged injector?
If this doesn't work, can anyone give me any other ideas as to what it could be?
Presumably as the message always refers to cylinder 6, it's only a problem in this area and nothing to do with air intake os MAS readings.
Many thanks
Firstly I have to admit to being a real novice with engines of any type but am loving learning about this fantastic car.
So far I've fitted a new quad "straight through" Adamesh exhaust...new mesh grill, replaced the thermostat and water pump, cleaned all of the wheel sensors, upgraded and fitted 20" BBS Persius Wheels, polished it LOTS and simply put have a stunning looking Pacific Blue with Ivory Leather interior XK8 Convertible....what more could a middle aged man want.....mid life crisis I hear you saying!!
However, over the past 6 months I've been plagued by an intemittent "Restricted Performance" message on start up.
Initially it occurred shortly after a service and on removal of the coil and plug I notice a little oil. As this plug is below the oil filler, I assumed that there had been a little spilage during the service!
Having cleaned the small residue of oil I replaced the plug and coil pack and initially all seemed fine and I thought that had solved the problem.
Alas, the next time I took her out for a spin, the same happened again.
At this point I should mention that she only comes out of the garage on good days and only covers about 3k miles pa.
I've now swapped the coils around and replaced the plugs with NGK IFR5N10, but once again the problem came back at the weekend.
I have just put a bottle of FORTE Advanced Petrol Treatment in the tank and am waiting to see if it makes any difference....could it just be a clogged injector?
If this doesn't work, can anyone give me any other ideas as to what it could be?
Presumably as the message always refers to cylinder 6, it's only a problem in this area and nothing to do with air intake os MAS readings.
Many thanks
Last edited by GGG; 03-07-2016 at 12:48 PM. Reason: Thread title typo
#3
#4
If its always #6, no matter if you've changed coils around or replaced the plug...its either continually getting oil into it (easily discovered) in which you'll be replacing the valve cover gasket...or it could be a bad connector or wire from that offending coil. They do get crispy over time! I can't see any other obvious reason for an isolated cylinder showing a misfire. Find it quick, however!
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#8
The boot is the little rubber part that insulates the coil from the head. It would have to be really, really degraded for it to be arcing.
Do the new plugs have oil on them as well? Can you take a photo?
this is a good reference to start troubleshooting your plugs:
Beakys Motorcycles SPARK IT UP!!!!!
I'm guessing your valve cover gasket is leaking slightly and allowing oil to seep into the spark plug well.
Do the new plugs have oil on them as well? Can you take a photo?
this is a good reference to start troubleshooting your plugs:
Beakys Motorcycles SPARK IT UP!!!!!
I'm guessing your valve cover gasket is leaking slightly and allowing oil to seep into the spark plug well.
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#13
Thanks again.
I've done that and will check them again, when the issue comes back!
In the last week, after putting the FORTE Advanced Petrol Treatment in the tank, on "cold" start up, it misfires slightly for 10 seconds or so and then clears up and runs perfectly. This hasn't generated any coded though, however I'm sure that after a bit more useage, the gremlins will return....if not this one it will be another!!
I've done that and will check them again, when the issue comes back!
In the last week, after putting the FORTE Advanced Petrol Treatment in the tank, on "cold" start up, it misfires slightly for 10 seconds or so and then clears up and runs perfectly. This hasn't generated any coded though, however I'm sure that after a bit more useage, the gremlins will return....if not this one it will be another!!
#14
Okay...it's back.
I haven't used the car for a few weeks and when she started up yesterday "Restricted Performance" was back for about 5 minutes, whilst ticking over and then it cleared itself.
I managed to pull the following codes....P0306, P1316, P0356 and P1000.
I've already replaced the coil pack, so running out of ideas.
I haven't used the car for a few weeks and when she started up yesterday "Restricted Performance" was back for about 5 minutes, whilst ticking over and then it cleared itself.
I managed to pull the following codes....P0306, P1316, P0356 and P1000.
I've already replaced the coil pack, so running out of ideas.
#15
#16
When the car is not being used, do you leave it connected to a battery conditioner, or is the battery left to slowly go flat?
Its always worth checking the battery on these cars when you start getting seemingly random problems.
Its always worth checking the battery on these cars when you start getting seemingly random problems.
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#19
A quick read suggests the injector's health need to be brought in the analysis...
Best of luck, keep us posted.
#20