X-type low compression and misfire
 

Just replaced the head gaskets and had valves redone on an 03 x-type. When put back together has misfire on cylinder 1,3,and 5. However when checking compression cylinders 2,4, and 6 have low compression. Just wondering if anyone has any suggestions. I have double checked valve timing, and checked for vacuum leaks on the misfiring bank as well.

RE: X-type low compression and misfire
 

Sounds to me like either your heads are not sealed to block or your valve job blows..hard to say..What made you do all this to an 03 anyway?

RE: X-type low compression and misfire
 

The owner drove it hot and warped the heads.
What your saying makes sense, I guess my big question is why isn't the misfire on the cylinders with low compression. Would you think this indicates a different problem.

RE: X-type low compression and misfire
 

I can't explain the odd mis-fire codes..I agree, don't make sense it's on the cylinders with good compresson..but who knows with the way these engines are monitored...If you can afford it..I would get new heads and not try to shave the old ones..they may even have hairline cracks and later fail completely.

RE: X-type low compression and misfire
 

Are the ignition coils operating properly? spark plugs OK? (er we are talking petrol here not diesel???)
An obvious one but can be easily overlooked is the valve timing correct and are the valve clearances correct?
If the heads are warped or not properly seated with the new head gaskets is their any sign of water in oil / oil in water?
I can see the point made re not having the heads skimmed, but replacing them, but don't a lot of workshops equipped to do this have the tools to test the integrity of the heads?

Mike

Okay so to make a long stroy short....the valve timing was off by one tooth on the exhaust side of the bank with the misfire. Got it put back together ran OK. Still a little bit of a shutter at idle. Took for a test drive everything was fine. Owner picked up car, when she was driving check engine light came on and it died on her. The codes that come up now are p0300,p0302,p0304,p0306,p1314, all misfire codes but for the bank that didn't have the problem last time. If you have any segestions I would appreciate it.

X type is very difficult to time you need a jag tech totime it.

It feels more like a fuel problem. It will cut out while accelerating at any speed but then a minute later it will be fine. I have never experienced it only the boss man and the owner have. I must have the touch with this car. The boss says it feels like fuel pressure drops off and then comes back.

check the vacuum reading at idle then hi revs

Fuel pressure drops to 44.4 when the problem happens. Normally is at about 55.

2003/6 XTYPE jaguar

It is always helpful to include the year, and engine type (perhaps in your signature tab? as most of us do). Also where you live (had to look at your profile to see AU).

https://www.ebay.com.au/itm/37372082...3ABFBMgNWsj-Vf

There are others if you search.