Hello Everyone,

I need your help, I have tried everything I could, now I need expert advice on fixing my 2005 Jaguar XJ Super V8.

I bought it last year in September, at an auction.

After it was shipped to me, I filled up the tank and took it on the highway. After 4,000 rpm the engine lost power and there was a ticking noise, check engine started blinking and restricted performance light came on. I went home, hooked the scanner, codes were for multiple cylinder misfires, and exact ones I don't know, but I can hook it up again and find out.

Bought OEM plugs and ignition coils, had my mechanic replace them, cleared the code and drove it again. Exact same thing happened again, around 4,000 rpm clicking or ticking noise from the engine and car loses power and check engine light blinks. If you drive it under 3k RPM car drives and shifts perfect and gets to freeway speeds easily.

Next step was to replace the MAF sensor, again used OEM parts. Still no help, doing the same thing.

Took it to Jaguar San Diego, they took few days and came back and said the following:

"scanned system for fault codes. Retrieve multiple misfire and CAN network faults. Analyzed fuel trim data and found it out of range. Injected smoke at intake system. Secured vacuum line. Test drove the vehicle using Datalogger and monitored injector pulse, timing, fuel trims, and other relevant data. Checked sensor outputs, Swapped oxygen sensors across banks.

At this point, camshaft timing must be inspected, requiring cam cover removal. client declined further diagnosis. "

Well, they charged me $330, to tell me all this, and wanted another $1400 to further diagnose it. and I declined.

After this car has been sitting in my backyard; recently I installed brand new battery in it and took it to another mechanic and had him remove the CAT's and drive it, he claimed it's doing the same thing.

I basically have exhausted all my options and money, I am seeking help/advice on what to do next. I bought this car for myself, and I haven't enjoyed it a single day. Can someone tell me whats wrong with it or what should I do next?

Thank you very much.

 

How many miles are on it and what or who told you to replace the coils and the MAF sensor? Posting the actual codes will help. Did the dealer give you a printout of the codes and fault messages they obtained? Any particular reason you removed the cats and did you keep them? Need more information.

 

2005 Jaguar XJ XJ Super Sedan 4D

RWD V8, Supercharged, 4.2L 96531 miles Silver Black

My mechanic advised to change the plugs and coils, it was throwing misfire codes.

and the MAF sensor he also asked for.

There are no codes on the ECU, only when the car goes above 4,000 RPM it gives codes, I will get those again.

I was researching these forums, and someone suggested changing the CAT, so I figured they must be choked or something, it happened to me once on a Mercedes E55 AMG.

no CATS were removed, they are still installed, the car is in complete stock condition.

Thanks.

 

4000rpmis right about were the secondery fuel pump should kick in .
So with a scan tool plugged in you need to monitor fuel pressure wilst replicating the symptoms . It needs 55psi at all times from the Primery pump . And should jump to 70psi
Above 4000rpm . If it fails to do so there is your problem a dead pump .
I have seen many cases of the secondary pump failing with no pump related codes . Just misfire or lean codes. .
So well worth a look . Try to keep the running time to a minimum as it will be damaging your cats .

 

Wow nice looking Jag and clean engine bay!

There is a drain under the cabin filter (located under trap door near windscreen) and

if this drain becomes blocked water can affect the ECU and cause problems.

It would be worth checking. I think the Ecu socket and plug is on the firewall.

https://www.jaguarforums.com/forum/s...ion-ecu-65038/

 

Wow nice looking Jag and clean engine bay!

Deleted

 

Does it vary strictly by RPM, or by load? With older, carburetor engines, a clogged fuel filter would generate a fuel starvation misfire at higher RPMs or throttle load. Since electrical has been taken care of, maybe check the fuel filter? Also, with the CAN network faults, check the ground points for corrosion. It doesn't take much to interfere with communications.

Dave

 

Any idea as to why the car was auctioned? Did the mechanic perform a compression check before installing the new spark plugs? Did you notice any fumes above 4000 RPM while you were driving? It actually sounded like the vehicle was starving for fuel at the higher RPM although I'm not entirely sure what was causing the 'ticking' sound. As others had suggested, you would want to check the fuel pressure.

 

My 05 Super V8 with 130k had this problem.

Pulled hard til 3200-3500rpm to where it began to choke up, ping and misfire HAAARD. real hard. solution? Clogged cats. seriously.

Good luck. something to consider.

 

I'm with Datsports on what to look for. Having the scanner monitor the live data will give you a clue.

As for the cat test you had your mechanic do, I'd think a bit differently. A blown cat could cause a muffler to clog. I would opt of a back pressure test. You can usually rent one for free @ an auto parts store and if not, they're less than $100. Test @ the O2 sensors before the cat and check @ the O2 sensors after the cat for a clogged muffler.

You can do a quick Youtube search for these tests. They are quick, easy and you aren't left guessing.

You can also use a vacuum gauge @ the intake manifold but I find the back pressure test is better as other things can create vacuum issues.

All that said, start with codes and live data and report back would be the best option imo.

 

Thank you, everyone, very much for the advice, I will work on it right away. I hope it works!

I will work on all of them one by one.

Thanks