I just had my engine replaced with a used engine in my Jag 2011 XF and after driving for about 100 yards the engine throws a low fuel pressure code and drops into restricted performance. The garage that installed it tried swapping high pressure fuel pumps, sensors and gave up. I took it to the dealership for hopefully better diagnostic equipment and they did the same thing charging me for new parts. Today they called and said they found that the timing is off by 90 degrees and want $4k to set the timing. They are confident this is the issue with the low fuel pressure. My question to everyone is, can a modern car run 90 degrees out of timing and run fine? The car drives with lots of power until it drops into restricted mode and even then I was driving 75 on the freeway with no ping no strange vibrations or strange idle, just can't go high RPMs. Any thoughts? I am not going to pay them $4k to time it, but plan on telling the shop that installed it to fix the timing since they screwed it up....just hate to have them do it and be wrong. I can't believe it drives 90 degrees out.

 

There ARE some contradictions in the story as you have it posted. You say the car runs for 100 yards, then codes and goes into RP. Then you say what happens at 75 on the expressway. Are you saying you get it to 75 AFTER it RPs, or that only sometimes it RPs in 100 yards?
But, you are right about a car not running with most any "timing " 90 degrees out. ! Surely they are not saying the ignition timing is 90 out. "Timing" is a general term meaning "ignition timing" in the old days. Modern cars do not even have adjustable ignition timing. Maybe they mean the flywheel timing or the cam timing. So, the first question becomes , "What timing are they talking about?".

You should go have a talk with the service manager and find out what they are really talking about. Then ask how the car runs fine until it goes into RP.

BTW, what is the exact diagnostic code number that you describe as "fuel pressure"?

 

I doubt the shop that installed the motor ever touched the timing. It depends on the type of motor (interference vs. non interference) if it would still run assuming we are talking about the timing chains being set incorrectly. It may come down to who sold you the motor not the shop who installed it.

 

Thanks for your reply. To clarify what I was saying, the car starts no problem, you start driving and after about a hundred yards or so, the RP light comes on. I had my coder reader and reset the code, but once again it RPs pretty quickly. If you floor it when it is in RP, the car doesn't accelerate fast but still drivable. I drove it to the dealership in RP on the freeway and was going 75 mph no problem.


I plan on going to the dealership today and talk in person, but the service guy explained that when they attached the motor to the transmission they could have turned the cam(can't remember his exact words) the wrong way causing the timing to be off 90 degrees. He said the compression was reduced in half due to this.


I think the code was P0087, but going off memory.

 

Attaching the trans shouldn't have any thing to do with motor timing so I'm not sure what the dealer was trying to tell you. Maybe there is something funky about the Jag motor that I've never seen before (I build and sell custom motors). Hopefully the shop that installed it can help so you don't have to fork over $4k to the dealer.

 

Yep, the Jag 5.0 HP fuel pumps not only have specific timing, they require 2 special tools and removal of a bunch of stuff (Like the front timing cover?) to do it right. Definitely a dealer trip. Your issue probable occurred during the HP fuel pump swap. I'd make sure the dealer is capable and warr. the completed work for sure.

 

That makes sense!

 

The High Pressure fuel pumps have their own dedicated cam drive on the lower left side of the motor.

 

In my copy of the 5.0 S/C Workshop Manual the fuel pump camshaft timing check procedure is shown on pages 885 to 892, and the fuel pump camshaft timing adjustment procedure is shown on pages 893 to 898.
The last three pages of each are the same engine oil level check procedure so no big deal.
The special tools needed are 303-1447 and 303-1613.

 

Good to know.

Does that mean the pumps are mechanical and they pull fuel from the tank vs. the normal electronic pump in the tank?

Is this new for the 5.0L or is this common on other Jag motors.

 

So I went to the dealer and they showed me what was wrong. Bigg Will was correct that the fuel pump timing is driven off a timing chain and that was off. Why Jaguar didn't opt to use computer timing is beyond me. Their explanation of what probably happened is if when you remove or connect the transmission to the engine, if you turn the fly wheel left instead of right to get to the bolts that connect the two, you mess up the timing because the chain slips off the gears (great design). They said you needed special tools to do the timing and had to pull the engine so they wanted $4k. I went back to the shop that installed it and tried to get them to pay, but after he looked into it, decided he could do it. He is just going to do the fuel pump timing and not the cam timing (part that engine has to be moved forward) since he doesn't think he could have messed that up by turning the flywheel the wrong way.


I wasn't going to pay $4k, so I had them button it back up and towed it to the shop. He will get his tooling soon, so hopefully this is the issue with low fuel pressure.

 

The 5.0 has a in tank electric pump that supplies fuel to the 2 stage High pressure pumps, I've seen over 2000 psi in my fuel system, not a pressure you want traveling long distance.

 

Got it. This is all due to the DI engine setup which requires the higher pressure. Any DI motor will probably have a similar setup.