Bad Gas or Bad Sensor 2006 X350 XJR
 

I have a 2006 XJR with 170,000 miles on it.

On Sunday, I stopped at a new Racetrac Gas Station and bought 13.981 gallons of premium. I have bought gas twice there before with no issues. I drove 20 miles after fill up and made three stops where I left the car.

Monday while driving to work (7 miles from start) I stopped at a traffic light and noticed the engine running rough. I continued another 7 miles to work and checked codes with an Actron code reader. There were 11 codes as follows:

P0300, P0301, P0302, P0303, P0304, P0305,P0306, P0307, P0316, P0171 and P0174.

I cleared the codes and on starting to return home several hours later, I got a lot of white/gray smoke when first starting that smells like unburned gas. Less than a mile into the trip home, smoke cleared up and did not notice smoke when stopped at traffic lights. I read the same codes after I arrived home.

My first thought is bad gas, but if so, why did I not immediately have the symptoms followed by the check engine light and the codes when leaving the gas station?

I next thought it could be a battery issue. At rest battery reads 12.24 vdc. After starting the car voltage is 14.42 vdc.

Could it be a water temp sensor that chose the ride to work to decide to fail?

Any suggestions before I take it to a shop to drain the gas?

Hi Mike,

Gasoline contaminated with water gets "blended" in the pumping process and it takes awhile for the water to separate back out and settle to the bottom of the fuel tank. So your symptoms could definitely be consistent with contaminated fuel. To confirm, pump a quart of fuel out at the fuel rail into a clear container and let it sit for 30 minutes or more to see if water settles to the bottom.

Your battery static voltage is too low, though your charging voltage looks proper. You might want to have the battery load tested.

Cheers,

Don

Don;

I tried looking for the fuel line where it connects to the fuel rail. I don't see the fuel line or the rail. The attached photos show the supercharged engine with the top plastic shroud removed. I went into the CD version of the service manual from Jaguar Heritage and don't see anything resembling the fuel line fittings in the illustration on the engine. I could not find the pressure relief valve seen in the illustrations. The pages that I printed were all for supercharged cars, so I expected to see something resembling the illustrations.

Next I tried a fluid transfer pump that I bought at Autozone. I snaked the clear plastic tube down the filler neck, but even at 48" long fully inserted the tube does not get wet with fuel. I wonder just how long is the filler neck?

Thoughts on access to an under hood fuel line?

Thoughts on maybe draining some fuel from the fuel filter connections?


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Hi Mike,

The fuel rail is hidden by many obstructions on top of the engine, but at least on some years there is a Schrader valve at the rear end of the right bank rail - you can see the projection in the parts diagram for the supercharged engines:
https://cimg0.ibsrv.net/gimg/www.jag...9893902b18.png

If you still can't find a Schrader valve, you should definitely have the Fuel Rail Pressure Sensor, part 4 in the diagram, which is on the left side of the engine near the firewall. It mounts with just 2 screws (disconnect the electrical connector before removing the sensor). Connecting a hose at that port wouldn't necessarily be convenient, but fuel is present there and if you can hold a hose there and have an assistant repeatedly turn the key to Position II for a few seconds without cranking the engine, you may be able to collect a pint of fuel.

The fuel filter fittings are a good choice, but it may be even more convenient to access the fuel pumps themselves, under the rear seat. The right hand pump is the primary one (actually, I think your '06 probably has only one electric pump and it is on the right side). You could simply disconnect the hose from the outlet of the pump and run the pump long enough to collect a pint or quart of fuel.

Disconnecting the rear seat for access to the fuel pump can be difficult, especially the first time. I believe photos have been posted somewhere in the Forum. There are two latches on each side, one near the outer corner of the seat cushion and one closer to the transmission/driveshaft tunnel. The latches have teardrop-shaped levers with the pointed end facing toward the front of the car. You have to push the pointed end of the lever toward the left side of the car until it unlatches. Sometimes it helps to also push down or lift the cushion, but with your hand between the seat cushion and floor pan you can't push down very much. Once you get the first latch undone, stuff the edge of the floor mat under the cushion so that latch doesn't lock again before you can get the next latch undone. When you get both of the latches undone on the right side, you can move to the left side of the transmission tunnel, then the outer left corner.

Cheers,

Don

I drained half a tank of fuel out of my XJR by disconnecting the fuel filter, connecting a hose to the fuel line, and cycling the ignition a million times. Each time you cycle the ignition the fuel pumps run to prime the system. Crappy method but I wasn't in the mood to remove the back seat and take out the pumps to get access to the top of the tank.

I was going to put the front of the car on ramps over the weekend to look at removing the plastic cover over the fuel filter and drain some fuel as Cambo suggested.

Although I was getting smoke with the car running, with the codes cleared, it was not running rough.

I added a bottle of Heet to the gas. Heet adds methanol to mix with the water. I drove about 10 minutes and the smoke cleared. I drove about 20 miles and no codes reappeared.

It seems to be resolved.

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Crappy gas.