Hallo all,

Just recently, (this morning), my beloved motor decided to, what felt like miss a bit. Given that it has done nothing but tipped down for days here, i thought it was a bit of water or moisture had got under the plug cover, and thought that at best it would be a set of replacement plugs and maybe a new cover. I did my usual thing a got a single plug and worked may way through the left bank (as you look at the car from the front), and that made no difference. Then proceeded to work my way through the right bank.

Upon removing the first 3 plugs i found them covered in oil. The rear most plug however, was fine. What on earth does this sound like. I cleaned out the chambers and cleaned off the oil from the plugs, started her up and she was running as normal. No apparent miss fire and the restricted performance message, which i was getting, has stopped. For now anyway!

Any ideas peeps?

 

Its also worth mentioning that i cant pull any codes from the car as i don't have an OBDII reader yet.

 

You need to replace the gaskets and oil seals in the valve cover. It is not uncommon for the oil to result in coil failure.

 

Cheers for the info. Anyone got any ideas as to part number as Ive been looking and only seem to find complete gasket sets are they are expensive here in the UK.

 

If you have the AJ27 engine you can use the fel-pro gasket set which is very inexpensive here. Maybe someone on your side knows if it is available there on ebay or another source.

 

Thanks for the info. Ive managed to find 2 kits on ebay and the main gasket seems to be tge same bur the smaller seals are different. How do I find out which type us for my engine?

 

Assuming we are talking about the MY2000 XJ8, you have an AJ27 engine.

 

The set for the AJ27 has black valve cover gaskets and the spark plug seals are single, not figure 8.

 

Cheers for the info peeps. Managed to find one on ebay. Unusually, all motor factors I tried let me down. Only wanting to sell me a complete engine gasket set! Just a few days and the missfire/oil prob will be sorted!

 

Ok, have recieved my replacement gaskets, are there any special tips regarding removal and refitting of the covers? Also, anyone know the torque settings for the cover bolts?

 

This has happen to both of my xjr's and one recently purchased x308. These cars seem to have a valve cover/spark plug o-ring gasket issue as they get older. You will need to replace the o-ring on the valve covers and might as well replace the valve cover gaskets while they're off to prevent further oil puddles which will cause a misfire.

 

Usually valve covers are xx or xxx in-lbs and hand tightening them is good enough. Start from the center and work your way out and re-check them after. I usually tighten it a little more then just hand tight, but that's just me because I'm use to working on commercial truck engines.

 

Cover bolt torque is 9 nM. Do the three at the center, in line with the spark plugs first, then work from center out, as mentioned above.

 

Thanks for all the info peeps. Now i know what im doing tomorrow. While i was ordering the gaskets i made sure to order a new set of coils and plugs. Might as well do it all at the same time!

 

On another subject, now i know i have the AJ27 engine, there doesn't seem to be a lot of coverage on the 3.2 lump on the US part of the forum. The engine seems sweet, and others i know here in the UK who have the same engine have never reported any problems. Are there any known probs with my engine given that its a year 2000 car?

 

Ok, I replaced all tge gaskets and seals and let her get up to temp and it looks lke theres no more oil leaks. However, upon restarting it went into reduced performance mode and was missing still. Does it sound like the oil has killed one of my coils?

 

Very possible. You need to read the codes to see if one of the cylinders has a miss-fire code.

 

OK, got a copy of torque and a adapter. Yeah i know its not ideal but its all i could get my hands on. Am getting 2 codes, P0356 and P0357. I looked at them last night and cant remember the details but does that sound right for coil failure? If i remember it was 2 coils that were heavily caked in oil before changing the seals!

 

While i wait for someone to confirm those codes for me, there is something about my cars previous symptoms that is puzzling me. Before i changed the seals and gaskets the engine would never go into reduced performance mode and start missing when it was cold. My journey to work is around 11 miles and even though i always let the engine warm a little before setting off, i would cover around 6 miles before the misfire would appear. Now after changing the seals, upon initial starting it runs fine then after 5 or 6 seconds, it goes into reduced performance mode. If it was a coil failure, would it not miss all the time?

 

The codes refer to 2 coil pack failures, cylinder numbers 6 & 7.

These are the two middle coils on bank B, ie UK passengers side.
See :
http://www.jagrepair.com/images/Auto..._numbering.pdf

- Alternate V8 Cylinder Numbering

You should have a P1316 misfire code as well.....

You can swap the coils around and compare resulting codes to confirm this.
The P35x codes refer to the coil packs, with "x" being the cylinder number.
The symptoms can appear a little random sometimes - mine were fine starting from cold, only throwing a code when the warmed engine was restarted after 1/2 hour or so after a stop.
The 5 - 6 second delay from starting is normal for RP codes in my experience.
AndyP