My 2009 XKR has always idled rough on cold start since I got it 6 months ago. Within the first minuet it smooths out and is fine all day. Today I got a CEL, P0303,P0305, P0300 and P0316. apparently 3 # and 5 are misfiring on cold start 303 and 305. 300 indicates multiple cylinder misfire which would be redundant since we know 2 cylinders are missing. Interestingly P0316 indicates misfire first 1000 revs which pretty much describes what is happening. After a short time it smooths out on its own and is fine. Im leaning toward a fuel issue, Maybe too lean or rich on start? I don't think its ignition coils since the problem goes away on its own when the engine warms up. This condition don't re-occure until the engine is again cold like overnight. Any thoughts?

 

Welcome to the forum.

Check LTFTs and STFTs to see if there's a fuel mixture issue when cold. Check fuel pressure as well.

How many kilometres/miles are on the vehicle? Have the spark plugs been replaced? What fuel is being used?

 

I bought the car with 115 K miles on it and have put 2K trouble free miles on the car. The car was allegedly serviced by the Jaguar dealer in Harrisberg PA. I don't have the details on the service but when I got the car i changed all the filters and they were all in good shape and genuine Jaguar parts.

 

It can still be a coil problem.

Try swapping them around and see if the fault moves too.

 

Well after closer inspection it seems that the plastic hose connecting the fuel pressure sensor to the intake plenum is cracked and crumbling in my hand. I did a temporary repair with a length of tubing and tried to start the car and it wouldn't start and there was a strong smell of raw gas. After a few attempts to start the engine with the fuel sensor disconnected and connected the car finally started with the sensor disconnected. I then got a message on the dashboard that the car was overheating after running for lest than a minute. OBD reader confirmed the fuel sensor was causing a problem along with the coolant sensor. To make a long story short I replaced the vacuum line with the somewhat correct Jaguar part and an aftermarket fuel pressure sensor. The car fired up perfectly. No CEL and the coolant temp sensor will go in the clove box when it arrives. How or why the coolant sensor introduced itself into the problem is beyond me and I am just glad it appears to be fixed.

 

Thanks for posting the cause and what you did to correct it. It may help another forum member down the road.

Check the available battery voltage with a voltmeter across the battery terminals. There should be a minimum of 12.6 volts present with the ignition in the OFF position.

Low battery voltage caused by a failing or weak battery can cause random DTCs and instrument cluster warnings. If the battery is approaching five years, it may be time to replace it to eliminate unexplainable electrical faults.

 

When I read your first post, my immediate thought was ECT sensor which signals the ECM to set elevated revs for rapid engine warm up. Interesting to see a FP sensor fault can give similar symptoms.

Graham

 

Thanks for posting the fix. Would you also be able to post the vacuum hose part # that you bought? I assume that you got it through a JLR dealer.

thanks again.
John

 

I don't have the part number for the hose. I bought the hose and the Vin# to the dealer and it like going for a doctors appointment. You can't even enter the parts department and see their exploded views and diagrams of systems. They come out to you in the service area and question you and then disappear and come back with a parts diagram that looks like it was drawn by a 5 year old. Its not very clear or detailed. The parts guy asks if thats the part and I ask him if its the part? They have my old part in front of them and the vin# for the car. His answer is that the new part is longer? since mine was crumbling in my hand my reply was I guess it is. Well the new part is a plastic hose with rubber nipples and a "T' connection but its about 12 inches too long. Being that its mechanically acceptable I am using it with a loop fashioned into it. I don't think I can make another trip to the local Jag dealer without loosing my ****!. Needless to say the miss on the first 30 or so seconds of start up is back and I am just waiting for a code to appear. Someone asked about the battery and its 3 months old and 12.8 volts static. Engine running the system is at 14.2- 14.5 volts. Just for exercise I am going to replace the spark plugs and move the coils around to see if I get another cylinder misfire code. If it shows a code and the misfire has moved then I will know that at least 2 coils are weak. In the mean time what were the original equipment spark plugs?

 

Can you post a pic of the crumbling part?

 

I do't have access at the moment but yes I can.

 

Is this the part?

 

That's what the dealer has access to unfortunately - this is from the Jag parts catalogue which is not easy to navigate - I think the part is number 7 in the diagram (C2P3419) that you may be referencing:

 

Yes That is the plastic pipe in the photo. That is also the diagram the parts guy showed me. The same print out. The new part which is shown is longer than my original pipe and mine didn't have the little barb attached to it to support it. I am guessing that there is an update somewhere where they made the pipe longer and rerouted it . The new pipe don't even come with the little plastic part which looks like a check valve of some sort that is attached at the "t". The puzzling part is that once the engine runs for about 30 seconds it starts to smooth out and within a minute it runs perfect. I am convinced that the plugs and coils aren't the culprit but for good measure I have ordered new plugs and I will move the #3 and #5 coils to #1 and # 7 position and see if it throws a code again. As a side note since the weather Here in the N/E has gotten cooler and cold this has appeared. It has been doing this for about 4 months but only recently set the CEL off. I have an aftermarket coolant and oil temp gauge and the misfire goes away before there is even any temperature movement?

 

So I decide to change the plugs and move the coils around and as soon as I started moving the air pipes I could see a problem The rubber boot between the throttle body and the "T" that joins the air tubes is completely disintegrated. I could lift the 'T" right off the throttle body. I have searched all the jag dealers parts sights and I can't find it anywhere.

 

The "t tube" rubber boot is not available as separate item - it comes as part of the T piece ( around $1000)

https://www.terrysjag.com/product/AJ811188.html

 

Wouldn't pay that for a rubber coupling , must be a way to make your own adaptor from plumbing wobble couplings.

 

Ya, there must be some pipe available - one guy posted a pic of a pipe from homedepot.

I'm having work done on my Jag - I asked the service dept to order this part in case it could be modified for the XKR, I'm sure the lip could be cut away:

https://parts.harperjaguar.com/oem-p...seal-nja3554aa

 

I just ordered a 3.5 inch by 3 inch silicone hose coupler from Summit racing for $19.00. This hose is designed for coupling intake pipes on supercharged motors. Its more durable than plumbing hose which I also considered but couldn't find it in 3 1/2 inch id. Think this will work fine. Then we will see if the rough initial start goes away. I did change all the plugs and moved the coils around to see if I get the CEL if the problem moved. The plugs were kind of sooty but the gaps were spot on. I don't think they are too old.

 

I used a 'racer boi' SPECTRE part from Auto Zone or O'reilleys that fit fantastically for like $15 including two worm clamps. Others have gone to Lowe's or Home Depot and found suitable fittings in the plumbing sections.