Hi. I began noticing a problem with my 2005 Jaguar XJ8L last Wednesday when I was driving down the expressway during the day. At one point, the engine began racing as if the car was suddenly thrown into neutral. I shrugged it off though as I thought that I simply drove over a icy spot on the pavement. Again, on Friday afternoon, while I was driving down the expressway, the engine began racing again (the tachometer immediately climbed). It acted as if the car was suddenly thrown into neutral again, and the same occurred Friday night as well. In fact, this seems to occur whether the engine is warm or cold.
In addition, while stopping at a stop sign, I sometimes also could feel a slight roughness while the engine was running. It wasn't until Saturday night when the 'Engine Malfunction' amber light then came on. Any thoughts? Thanks.

 

you need to read the codes otherwise its a needle in a haystack
sorry

 

https://www.ebay.com/itm/LAND-ROVER-...pe!49503!US!-1 (Jaguar XJ8 Code Reader)

Would this code reader be suitable?

 

maybe but you need to ask the seller so if it doesn't do what you want you can return it. Most just do bog standard engine codes so may not read some jag specific or gearbox codes. A bad reader is about as useful as no reader

 

Yes the N510 it reads Jaguar specific codes. You probably only need a generic reader for an engine code but you might as well get one that can read chassis, body too. Shop for one that doesn't charge a restocking fee if you want to return it.

 

Well, I just got through ordering the NT510 so we'll go from there. Thanks guys!

 

Well, here are the codes that I got with the NT510 today.


Pending Codes:
P0303 Cylinder 3 misfire detected
P1316 Injector Circuit\IDM codes detected
P1111 Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage

Stored Codes:
P0303 Cylinder 3 misfire detected
P1316 Injector Circuit\IDM codes detected

 

How old is your battery?

 

The battery is 2 years old.

 

Well, it looks like a nice place to start with this is by picking up another air filter, and cleaning the MAF sensor.

 

MISFIRE MONITOR DRIVE CYCLE
1 Record flagged DTC (s) and accompanying WDS DTC Monitor freeze frame(s) data.
2 Fuel level > 25%.
3 Start the engine at a coolant temperature lower than the recorded freeze frame value (from Step 1).
4 Drive the vehicle to the recorded freeze frame conditions for 4 minutes. If CHECK ENGINE MIL flashes, lower the engine speed until the flashing stops.
Note regarding misfire monitor DTCs:
If, on the first trip, the misfire is severe enough to cause excess exhaust emission, the individual cylinder DTC plus DTC P1316 will be logged. The CHECK ENGINE MIL will not be activated. If the fault reoccurs on the second trip, the individual cylinder DTC plus DTC P1316 will be flagged, and the CHECK ENGINE MIL will be activated.
If, on the first trip, the misfire is severe enough to cause catalyst damage (more severe than excess exhaust emission), the CHECK ENGINE MIL will flash while the fault is present and the individual cylinder DTC plus DTC P1313 (bank 1), DTC P1314 (bank 2) will be logged. When the fault is no longer present the MIL will be deacti- vated. If the fault reoccurs on the second trip, the CHECK ENGINE MIL will flash while the fault is present and the individual cylinder DTC plus DTC P1313 (bank 1), DTC P1314 (bank 2) will be flagged. When the fault is no longer present the CHECK ENGINE MIL will be activated.









I interpret your codes to mean you have a bad injector circuit @ Cylinder 3 and that's where I would begin my troubleshooting. May be easier to eliminate a bad plug, determine you're getting spark at the end of the plug first. Ensure there's no obvious signs of wiring damage on the injector and that its plugged in properly. Swap the coil to another cylinder and see if the code follows (that will tell you your coils' bad)

Edit: You can pull and swap spark plug to another cylinder. Does the code follow? Yes - spark plug is the problem.
No? Swap the coil with another cylinder does the code follow?
Last, swap the injector but careful of the o-ring seals. If she's a high mileage, get replacement seals in advance. Same dance on all of these really. Cheap to do, until you find the problem;-)

 

Well, I replaced the air filter today as it was visibly dirty, and I cleaned the MAF sensor while I was at it even though the MAF sensor did look clean. During the process, I managed to break off the plastic clip retainer that was part of the MAF sensor electrical jack, but I would imagine that it wouldn't have been the first time that something like that happened. I'll have to keep it secured with some small black cable ties or something.

Well, afterwards, I gave the Jaguar a short 2 mile rigorous test drive, and it performed flawlessly. Time will tell, however, so I'm likely going to know better by tomorrow.

 

I assume you cleared the codes? I'm not sure how you concluded MAF sensor was the place to look from the codes that were thrown. Can you elaborate Rick?

If or when it comes back, give my post above a try.

 

P1111 Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage

Thanks for the very helpful suggestions Sean. The P1111 code actually led me to clean the MAF sensor, and replace a very dirty air filter during the process. Yes, if this doesn't work, I'll certainly look into the #3 injector circuit (as that would obviously be next). Thanks.

 

P1111 is a pending code. That's not your problem:




From page 3: If DTC P1111 is flagged after DTCs have been cleared, all engine management OBD diagnostic monitor drive cycles HAVE BEEN COMPLETED.

 

Well, I'll keep my fingers crossed, and I did clear the codes afterwards.

 

Well, the 'engine malfunction' amber light did come on again this afternoon (along with the usual symptom), but it'll likely be at least a week before I get the opportunity to look into the Cylinder 3 misfire as Sean had previously outlined.

 

Sorry to hear Rick. Minimize the use of the vehicle if you can. If the misfire is bad enough, you can damage the catalytic converter. please keep us apprised of your findings.

Also, once you fix the problem, the light will go out on its own. So if the code follows the swaps, once you fix them, you shouldn't need to clear, just let the amber light go out by itself.

 

Hmmm.......Well, I might get a chance to check out the problem with the No. 3 cylinder over the weekend. By the way, can someone tell me where exactly the No. 3 cylinder is located? I seem to have trouble finding a reliable cylinder number location guide. Thanks.

 

Here you go...........