Okay, so I just did a full tune up this week, filters, plugs, oil, etc.. My car was running great for the past days, better than ever.. So today I got bored and I was playing with my intake again and I wanted to see what would happen if I removed the tube that pulls air in from the grill.. I removed the two screws holding it on, took it out, and went out for a drive.. I made it out of my neighborhood, got on the gas and it drove great.. for a mile. Then it got pissed off at me, the exhaust started making a low pitched rumble throughout the rpm range and the engine had not power.. I immediately went home and put the tube back on and took the car back out, but still had the same low pitched rumble coming from the exhaust (sounds like it has a big cam or something) and on the second drive the "restricted performance" light came on as well as a blinking check engine light.. So then I went back to my house and unplugged the battery and let the car sit for 45 minutes to an hour and started it back up.....

Now I have a HUGE problem.. The idle is really rough and the engine is making a really bad knocking noise that sounds like it coming from around/underneath the supercharger.. I have the extended warranty, but I only use the dealership in ft. pierce which is around 2 1/2 hours away and it doesn't sound like it's going to make it that far.. (I have a closer dealership, but their thieves and don't install anything they change you for (and I'm friends with the owner)) The knocking noises is really bad, and got worse after the reset.. My friend thinks I leaned it out too much with the intake off and blew a ring.. I know one of you techs must have an idea... My code readers broken, but I don't feel like the car is going to know the problem anyways.. Also don't we have a tech in the Ft. Lauderdale / Miami area?? My warranty company will pay you directly and doesn't argue about prices if you would be interested....

I'm usually on here to help others, but now the tables have turned.. So if anyone can figure this out I would be very grateful.. Eric

 

Did you remove the air filter box? If so, what are the chances you had a loose washer or some other foreign object suck into the engine? A knocking noise from anywhere in the engine is bad. If it did go lean, you could have burnt a piston or broken the top ring land. If you want to check out how severe the problem might be, do a compression check or leakdown check of the engine. At least then you'll know how deep the problem could be.

 

You removed the tube prior to the air cleaner, right?

Fact is, you really should have checked the code instead of just disconnecting the battery but that can't be changed now. I doubt your problem is running lean. The mass airflow sensor would automatically change the computer settings and you wouldn't really notice. PLUS, despite what alot of people think, manufactures do certain things for certain reasons. I am willing to bet that you starved the engine of air and what air it got was heated air from the engine compartment. Your car probably read the sensors input as running rich then read the air as being to hot. NOW, I am unsure about jaguar but seeing as how they are a more upper end company, I will go out on a limb to also bet that the ecu is quite good at taking data and adjusting engine controls. Seeing as how your engine is supercharged, it is most likely EXTREMELY sensitive to intake air temperatures. If it saw a spike in IAT, it would immediately begin to adjust the timing. Now, hopefully it does not have a test mode in which it tests the IAT sensor before adjusting the timing because that would have been more then enough time for the engine to begin detonating. I have sets of the pistons they use in these engines in my garage and can personally say that if any bit of detonation occurs, I doubt the pistons would live, they are very brittle.

HOWEVER, on a postive note, if the timing is askew, then there is a chance that is your only problem. However, the problem with alot of newer cars is if their timing is severly off, the car's computer doesn't know how to adjust so it does not adjust it. If you have a good code scanner you can hook it up and start the car for a few seconds, find out what the timing is at and call your dealer or a friend or post on here and have someone do the same with their car.

That's about it for simple diagnostics, as suggested, a leakdown or simple compression test would be the next step.

 

theres no reason for timing to be off and if theres a fault with knock sensorsyoull get a ck eng light. also disc the battery and erasing ck eng lights is old school, CEL are retain in NON volatile memory, meaning if you did a hard reboot, the only thing you do is clear window, sunroof, radio clock memory, and it reset adaptation in ecus(all ecus) to factory defaults. Youll clear a pending code or ones that are of no consequence to operation, but what your experiancing will not go away, and theres a difference between the light turning off and the code going away

 

[sm=closed.gif] move it to General Tech Help

https://www.jaguarforums.com/m_78868/tm.htm

 

Your wish is granted STR...hope it works out alright...