after fuel filter swap car idles now but very rough I have po codes for cylinders 246 I have new coils on the way. Is the passenger side head odd in number or is it drivers? At this mileage I am almost thinking I should replace the entire lot of coils. Besides the po cylinder codes I am still getting the po316 and the po1000. Thanks

 

The XJ's don't have any unusual coil issues -- they fail but not like the Porsche/ Audi/ VW problem -- it is unlucky that you would need all of them.

My XJR always get premium fuel -- I could tell the difference the one time I had to use mid-grade on my 98VDP. Did you fill it with 98?

 

Have you added a fuel additive?

 

Just out of interest, maybe try cleaning the MAF as I described earlier, follow by doing a hard reset, then see where we're up to...

Hard reset reboots your car's computers. Undo the neg strap off the battery and hold it to the pos post for 20 seconds, this clears the memory.

Fire it up, let the throttle recalibrate and see how the idle behaves, you might just have an upstream air leak.

 

Each time that you have improved the fueling things have gotten just a bit better. Have you measured the fuel pressure as being 40+ psi at all times? If it is not, you will experience lean fueling which would lead to your detonation and pinging. The ecm assumes that the injectors are spraying at that pressure.

Since you bought it as a bank repo, perhaps it has sat around long enough to gum up the fuel pumps.

 

Sounds like the next step might be a compression test. You are well outside Nikasil worries, but there is always a chance something has come apart in a cylinder.

Water in the tank can be a problem, and new fuel on top of water will not fix it, of course. Use the fuel pressure test hose to draw a little fuel out and have a look.

My experience is that the XJ8 is pretty good at discerning the correct misfire cylinder, so there is a good chance you have some common issue. The knock sound worries mr. though- Broke piston?

 

yes 3/4 of a tank of 98 octane with no ethanol

 

yes the fuel additve you forum suggested

 

Hello again update 5

Fuel filter changed was kinda gummy but not too severe. Did the battery hard reset. No real difference except that the car did adjust the throttle to gain a idle but a rough one. I was able to take to coils new that I had local and place them in the passenger side engine bank the two middle ones. I did this because the original plugs in this location had the most carbon build up. This produced some difference but not enough to call it a day. The codes after this are still po1316 then direct cylinders. After the Hard reset I get the codes Po302 Po306. If the car does infact stall i get the flash code or pending codes of po302 po304 po306 and po 308. However if I turn the key off and terminate engine running with the key on 302 and 306 will record. While considering the firing order Am I correct Drivers is Even and Passenger is Odd with cylinder one being closest to bumper on passenger side bank? The vehicle is running better but still a very rough idle. Fuel pressure does check on the rail to be with in accurate measure. The compression also does check fine with in range.

I think I am almost there but just have to figure out the remainder of the problem thank you for your continued help.

 

Your numbering is correct for your specific model year - The numbers changed in 2002. There had been plenty of confusion in previous model years due to the difference in Jag's numbers and the OBD numbering configuration

 

hi pyatsko,
have you tried reseting ECM adaptation? when you repair a management problem,ie;coils maf sensor etc,jaguar recomend this procedure,not that they will tell you.
jaguar service bulletin 303-01,drivabillity concerns after repair:reseting ECM adaptation.
1:apply parking brake allow engine to reach normal operating temp in park
2:turn off climate control
3:apply sevice brakes move gear selector to D(perform steps 4>7 with brakes applied and selector in drive)
4:allow engine to idle for 2 mins
5:gradually raise engine speed to 950 RPM. Hold for 45 seconds.
6:raise the engine speed to 1200RPM. Hold this speed for 45 seconds.
7:riase the engine speed to 1500RPM. Hold this speed for 30 seconds.
8:allow the engine to return to idle. Move the selector level to P and allow the engine to idle for 2 minutes to cool the transmission fluid. Switch off th engine.
WARNING PERFORM THIS PROCEDURE WITH THE VEHICLE ON A FIRM SURFACE AFTER ENSURING THERE IS NO RISK TO SURROUNDING PERSONS OR PROPERTY
!!!! DO NOT EXCEED THE ENGINE SPEEDS AND TIME DURATIONS LISTED.
Ive used this procedure countless times,ONLY AFTER EXHUASTIVE INSPECTION OF THE CHAINS AND TENSIONERS(REPLACE IF IN ANY DOUBT)
REGARDS NIK.

 

a friend of mine at jaguar is getting me 6 new coils to try apparently they do this in service all of the time I am going to replace all 8 and if codes go pull one at a time to get the codes back. I am down to almost half a tank of fuel does that have any relation? I would think not but seeing as how it was sitting almost 3 weeks at the bank. Any how them more I learn about these cars the more I like them. Thanks for the continued help I just have to say things are a hell of alot easier on a 1976 air cooled flat six turbo.

 

ecm reset will work as long as you have more than a quarter of a tank
regards nik
ps,let me know how you get on with the new coil packs.