Hello guys,
i’ve Just bought a 99 XKR convertible as it’s been my dream car since it came out. It’s in a very good condition (I thouht) but have been problems with it since day one. I’d appreciate the help, as I’m running out of options.
the car had 120k/km on the clock and was regularly maintenained by jaguar.
On the way home from picking it up, it showed the restricted performance message on the screen. I read the codes immediately, it showed p0352, p1646, p1647.
i went to the shop on the next day to change the ignition plugs. The 4 on the right side (passenger side) were heavely rusted, so I changed all 8 and cleaned the coiles. This worked well, I stopped getting the restricted performance message but the car still had a rough idle sometimes and did show the p1646, p1647 Codes. I also experienced a loss of power, which happened while driving. No codes no, messages and it went back to normal after restarting.
So I changed the uptake O2 sensors which was a pain in the *** if I’m being honest! The codes didn’t come back, but the rough idle and power loss were still there ( intermittent like before ).
while driving in a traffic jam it showed the restricted performance message only for brief seconds.
There were no codes at this period!
the rough idle became more noticeable (especially when the car was warm), then it showed the restricted performance message. I read the codes immediately and it gave the p0300 and p1316, which even after reading about them didn’t tell me much (help appreciated).
i checked under the bonnet again only to find a small hose sucking air. it comes out of the supercharger and doesn’t connect to anything! I took a few photos of it just in case.
I tried to find where it should go with no luck. I noticed that it is one of two bifuricating from a Hose coming out from the back of the supercharger and right in front of the throttle body.
I let the car cool down and stuffed the hose with a screw (following the advice of the car mechanic).
It drove normally at first, then when it warmed up it started with the rough idle, stalling and the RP message came up again. I couldn’t read the codes as the message disappeared after a few minutes.
im planing on changing the fuel filter in the upcoming days, as I noticed that it hasn’t been changed in a long time, but i don’t believe it could trigger all these problem.
i’d very much appreciate your help for options for why it’s acting like this and for the hose that doesn’t go anywhere!

Regards
Rheys

 

Hi Rheys and welcome to the forum.

P0300 random misfire and P1316 are related. I've attached some snips from the DTC guide, courtesy of Gus' brilliant reference website:
http://www.jagrepair.com/DTCforms/aj2799.pdf. (3)

and from JEPC which should help you trace the hoses - 1 is air assist, 2 is the part-load breather.

Beware that the P1316 flags excess emissions, and possibly cat damage, so don't drive the car more than you have to until you get this sorted.

Deal with the air leak first, and you may find the other codes go away. Possibly someone has attempted to replace the part-load breather with fuel line? I doubt that the dealer would do so as he would much much prefer you to buy an OEM replacement

I cant give you proper guidance on this as my car is older and non-supercharged. The plumbing isn't identical, although I'm sure someone with better knowledge will chime in to steer you in the right direction.

Please drop by our new members' section when you get 5 and tell us a little more about you and your car:
https://www.jaguarforums.com/forum/n...-intro-must-5/

Good luck!

Mike

 

Thanks for the reply,
i did check the DTC guide, but I still don’t understand why it would misfire! ans only when it’s warm!

do you happen to have the JEPC, as the links I found on the website seem to have been expired.
The diagrams where helpful but I don’t believe that the hose is on there.
Ill give it a try again today and see what happens.

Thanks a lot.

Regards
Rheys

 

As it is a 99, something else you should check are the timing chain tensioners. I would make sure these have been updated before doing anything else - if you don't know, take one of the cam covers off and have a look.

 

The tensioners habe been updated.

it did show the RP message again and I was able to read the codes.
ive got a p0300 p0305 p0306 p0307 P1316.
i don’t know how this could happen when the plugs are new!

 

Any hose off needs fixing. Especially if it causes an air/vacuum leak!

Other issues could be wiring etc - see if they share fuses/relays/looms etc

Note P0352 is a coil issue not plug.

Changing plugs was unlikely to solve things relating to coil/O2 sensors (or wiring/fuses/etc)

 

Sounds like you need new coils.

 

Dumb up for the coils. The rust you found is likely caused by water entering via the bonnet or coolant from the extension reservoir. The liquids short cut the coils and damage them over time. You can easily verify faulty coils by swapping them with those from other cylinders. From your latest codes it looks like Cylinders 5,6 and 7 are affected. Take these coils out and swap them with cylinders 1-3 and then do a test drive. If the problem moves, the coils are likely the issue. Make sure you clean out the whole area around the plug from any dirt, rust oil or water.
Chris

 

+1 on the coils.

 

PS. Forgot to say, but when you swap coils, the problem may not move immediately.
It make take a couple of cycles before a code is shown on the new cylinder, which could be misleading.

 

The open hose is probably not related to the breather system. To me this looks like the connection to the superchargers bypass valve

 

So mates, thank you very much for the replies.
I checked the coils again today, only to find them swimming with what I’m assuming is rain water!!
i dried the coils and the cables and checked the plugs, all seemed to be fine. The test drive afterwards was much much better! No rough idle or RP message! Of course that was just one test drive, but I’m hoping for the best.
the car was out in the rain for only a night! So I assumed that the seal on the plastic cover was faulty and added a bit of silicon seal to it.
im going to check the car for the next couple of days and let you know what happens.
i checked again for the other end of the hose with no luck. I couldn’t seem to find it in the workshop manual either! I did notice though, that the throttle body is the new one with the electric sensor on the side, which I find to be a bit strange for a99 model!
i do think that the hose should connect to the throttle body some how. Would that be logical?
regards.
Rheys

 

So I’ve been trying the car for the last couple of days. It did lose power a couple of times with no RP or codes!
the idle is much smoother, but it did idle roughly a couple of times to the extent that I parked it to cool down!
any ideas?
regards
rheys

 

Coils don't always recover and anyway die with age.

 

But since I cleaned the coils and dried them, I haven’t been receiving the codes. I did however realize that when I drive on the motorway or on trips that don’t include start stop driving, the car rides much smoother.
In the city, after about half an hour, it would start jerking like an untamed bronco.
cheers

 

When you say 'untamed bronco' are you possibly getting the ignition interrupt at 3000 rpm's as you accelerate away from a stop or from slow traffic? Usually there's a restricted performance light as a warning but it's easy to miss if you unfamiliar with it?

I too would suspect a coil or coils as well based on your d3escription of events and with rusty plugs indicating water sitting there over time I'd have serious questions about just how "well maintained" the car really was !!

Misfires and vacuum leaks on these cars can be a real PITA to track down and cure.

 

There’s no restricted performance message neither igtition interruption. I meant that it sometimes idles roughly and the engine starts getting uncomfortable or even misfiring. There are no codes.
the car was well maintained by jaguar throughout its life up until about one to two years ago. It was then parked for a while as the owner passed away.

 

Is it even running closed loop?

Watch fuel trims when it's OK and also when idles rough.

But everything points to coils so do something about them! Buy a tester or replace coils or whatever - it's not going to fix itself.

 

How do I know if it’s running in closed loop?

 

CL -> OBD.