I'm hoping someone has some insight here because I have no idea what's going on.
My 2008 XKR (105K miles) starts from cold and idles horribly. It's basically mostly firing on 4 cylinders.
The check engine light comes on or even flashes on bad days and tells me we're in restricted performance mode.
I drive it a couple of miles in this super economy mode, switch off and read the codes. (Other people listen to their stereo, or text their grandmother!)
I get P0301, 303, 305 and 307. Misfires on every cylinder on the right bank. I also get P0316 misfire on start up, and P0300 random misfire.
The right side of my V8 is basically not working. If I wait a couple of minutes clear the codes and start up, then everything is OK. i.e. From warm it's relatively happy.
I don't think all 4 coils will go bad at one time or all 4 spark plugs, but I'm an optimist and switch the coils from right to left. No change.
I install all new plugs. No change.
I clean the MAF sensor on the right side. No change.
I then build a smoke leak detector from plumbing bits that I learned about on YouTube for $50 (when I could have bought a cheap one for $69 on Ebay!!). But anyway, I run smoke thru one of the inlet snorkels, and guess what? I choke a little on burnt lavender baby oil but no leaks. (OK, I haven't run the smoke by the MAF sensor part yet as I'd have to block off the air filter, etc etc.
So, what is common to just the right bank and can mess it up from cold?
I know, it's the Right Bank Cold Start Messer-upper Configurator, costing $3.50 and held on with one easy access bolt on the top of the engine. Ha , ha, dream on!
Last night, I even pulled all the plugs and ran a compression test. All the cylinders gave me around 150 psi. (Engine was cold)
Ok, that's it. I have no idea what's up but I'm hoping someone else will have some laser insight into my in-line 4 cylinder Jaguar.

 

If it's not ignition (and you've eliminated this by switching coils and changing plugs) then ignition harness or fuel injectors are the next likely culprits.

Graham

 

Most likely fuel injectors. Many of us have had the same issue incluiding myself and each time it's been fuel injector related.

 

Open your oil fill cap and check if it smells of fuel. If it does, than an injector has failed. Oh, and do NOT drive it if you don't have to! Fuel in the oil breaks down the lubricity and it will burn stuff up.

 

Unlike the 5.0L models, your 2008 4.2 L XKR has a real, old-fashioned dipstick! That makes it easy to determine if there's gasoline (petrol) in your crankcase. Simply remove the dipstick and smell it. Also, if the dipstick shows it's overfull, that's an indication there's gasoline (petrol) in your oil and the likely cause is one or more faulty fuel injectors. Too much gasoline (petrol) in the oil can overfill the crankcase and make it impossible to start the engine or possibly cause an explosion, as the vapors are highly volatile.

As Cee Jay said, if there's gasoline (petrol) in your oil, running the engine can cause catastrophic engine damage. Gasoline (petrol) compromises the film strength of engine oil and impairs its ability to protect moving parts from excessive friction. Have your car towed; don't drive it unless, of course, you can repair it and change the oil and filter yourself. I'd change the oil and filter twice; the first time with inexpensive oil to flush out any remaining "bad" oil, and the second time with your usual high quality oil and filter that meets the Jaguar specs.

 

Ballz, I didn't notice the 2008 part. My bad.
Please feel free to ignore me.

 

So, according to the bad injector theory - somehow all 4 injectors on just one side are coincidentally going bad at the same time. I can believe that a couple might have been going bad for a while and the previous owner just neglected them (the car is new to me) but all 4 seems like a stretch. And what does going bad mean? Leaking all the time? Or spraying poorly? Plugs 3, 5 and 7 were wet when I pulled them and I'm pretty sure it was fuel. But that also could simply have been because the mixture didn't fire. If there's something bad in the coil harness, then it has to be bad for all 4 coils (once again, unlikely unless there's a common ground), and then again it has to be worse from cold (also unlikely.) If the injectors are slowly leaking, then if I pull the plugs after it sits all night, I should see wet plugs right? Maybe I'll try that tomorrow. I just went out and smelled the oil from the filler and the dipstick. Smelled like regular engine oil to me.

 

What was the oil level on the dipstick?

 

The ONE INJECTOR FAIL scenario will only happen on the Direct Injection 5.0 model as follows.......
If one fails, it remains full-open, and the high pressure pump fills that cylinder with as much fuel as it can, which lowers the high pressure fuel rail's pressure drastically. Therefore, there is a greatly reduced supply of high pressure fuel available, which means that the other three 'good' injectors don't get anywhere near enough fuel to operate correctly, if at all. The excess fuel in the faulty cylinder fouls the spark plug which means no ignition is possible, and all that fuel somewhat hydrolocks that particular cylinder on the compression stroke, which is a very bad thing. With all that extra pressure, the fuel in the head at TDC gets forced past the rings and into the crankcase, thence fouling the oil with gasoline which drastically reduces the lubricity of the oil, causing even more problems.
Therefore, if this happens, DO NOT DRIVE unless it is absolutely necessary! Doing so could seriously damage other components.
Remember, this only happens on the 5.0 GDI engines.

 

This same problem happened to me with a Mercedes 240 from a friend.
It threw us the same error codes and we began to check coils, high wires, spark plugs and there is no way to eliminate the fault that was exactly as you describe.
In the end, it turned out to be a problem with the supply of gasoline, specifically, little gasoline pressure arrived and when it was burned badly, it threw those errors even the fault of the lamda probe.
We had to change the pump units and gauges and the problem was solved.
It was a very difficult fault to figure out and we went crazy to see the error bugs. The luck we had was that we did not change any injectors because it would have been absurd.
My experience was this.
Check pressure and fuel supply at idle and running.
I hope I've helped.
Greetings.

 

https://www.ebay.co.uk/itm/Set-of-8-...-/264581376812

Indicates you should be able to get 4 for around the $500 mark, not sure how easy they are to change on a 4.2 X150, I remember on my X100 it took me around an hour to change all 8,

As has been stated, if you can smell petrol in your oil you need to drain flush the engine with some cheapy stuff, drain and fill with good stuff*, and don't run the engine afterwards until you've changed the injectors.

*It'd also help to change the oil filter at least twice too

 

......... and it's very exciting when you're 2 countries and 1200 miles away from home with another 800 miles to go.




Four days in the local Jaguar Dealer to get a new injector, change the plugs and engine oil. That puts a dent in the holiday budget.

Graham

 

Dude, 1200 miles in ANY direction wouldn't even get me out of MY country. I'd have to go 3000 miles to get to a third, and that'd be Guatemala. I'd not want to be stuck there with a broken Jag.

 

No matter how bad things are, be thankful that it could have been worse and you're still here.

You suffered some pain in the wallet and a change of plans, but you were still on holiday and made the best if it.

Fortunately, you weren't in Texas when the lights went out - and everything else. Life is full of blessings, but sometimes we don't see them. That becomes more apparent the older we get.

 

Re: Mercedes 240 similar problem. That doesn't fit my scenario because I don't believe there are separate fuel supplies and pressure regulators for each bank. If the fuel supply was low or too high, it would affect all 8 cylinders.
The oil level is normal. This is a 4.2 not the 5.0. I think the gushing fuel injector scenario wasn't an issue on this engine.
Mark

 

I've been there, done that, too.

Around 30 years ago, I rebuilt the Holley 3310 carburetor on my modified '60 Vette. I did the work in my garage, and when I reinstalled the carb the car started right up but ran rough. While I was fiddling with the carb adjustments the engine stalled and died. I smelled gasoline and when I tried to start the engine it wouldn't crank. I checked the oil level and it was way overfilled, so I knew I screwed up when I rebuilt the carb. The float must have been hung up and fully open, pouring fuel in with nowhere to go except down the cylinders and into the crankcase.

I was lucky. I changed the oil and filter twice, bought a new rebuild kit and followed the instructions, reinstalled the carb and it started right up with no problems.

 

if it ran like crap all the time i'd say the cam chain tensioner could've lost a pad and jumped a tooth, it's rare but it can happen with the 4.2. you get to do the valve cover gaskets while you're in there anyway.

 

I think it would easily get you out of the United States ........?







Graham

 

if it is the injector, get it fixed. now. Or pay for new catalytic converters later.
In the life of my car I’ve purposely changed the injectors. Preventative maintenance learned by the replacement of my cats in the past.

 

Don't just throw parts at it. Injectors are not cheap and on your 08 XKR it is a pretty involved job.

- check fuel pressure as mentioned above (before starting, during, and at idle) - when was the last time the fuel filter was changed?
- swap spark plugs and coils from 1 side to other
- check and clean injector electrical harness + connectors (each bank has its own harness)
- check for damage to the catalytic converter? Maybe even swap the O2 sensors from 1 side to the other

I would lean towards a cat/O2 sensor issue since you mentioned it gets better as the car warms. Worst case, you can take it to a pro and have them give you some insight.