Hello All,

My name is MJ and I'm new to the forum. I've recently bought a 2011 Jaguar XJL Base with naturally aspirated 5.0L V8 engine. I knew the car had an issue when I bought it but since I enjoy working on cars I got it so I could work on it as a project. However, I'm not sure if I'm diagnosing my issue correctly so I wanted to see if anyone here would be able to give me a hand or a tip. Here is the situation:

When the car is cold, it starts right up but it idles rough and almost dies. Within a few seconds the computer throws Restricted Performance message and the car starts to idle smoothly the moment that happens. The fuel rail pressure code P0087 (fuel pressure low) comes on and my OBD scanner shows the value of 390 kpa well below the 800 (the scanner shows it should be between 800 and 3000). It goes like this until the car reaches the operating temperature. Pretty much the moment that happens you can hear the high pressure fuel pumps changing pitch to a higher sound. Right then the scanner value for fuel pressure goes way higher, way above the range (I think I saw it as high as 16000kps). The car throws the P0088 error. When I clear the errors while the car is hot, the P0087 goes away and reduced performance message goes away but the P0088 one does not as the fuel pressure value continues to be way too high according to the scanner. When I drive the car like that in about a minute or so the check engine light comes on but the car continues to run well. It performs as it should.

Here is what I have done so far. I changed the high pressure fuel sensor on the fuel rail. That did not do anything, the issue remained as described. I also replaced both high pressure fuel pumps and the issue remained as described.

At this point I'm not sure what it is but I know that it's possible that the timing chain for the high pressure pump might have jumped a tooth which I have found could cause this problem. However, before I go on disabling the whole thing to get into the timing chains I wanted to ask here to see if anyone has any other ideas.

To help, I'm attaching a link to a video that I took while my engine was running already at temperature. I'd have a hard time describing the noise that I'm hearing so I thought a video of that would be helpful. The first part is of me recording on top of the engine. It sound a little bit like ticking (maybe) but that might be noise typical of GDI engines? I'm not sure as I have not owned this car before so I can't compare. The second part of the video is under the engine. You can hear this noise that would be best describe like a snare sound when someone plays the percussion. It comes at somewhat random intervals but you can definitely hear it. I'm guessing that whatever is making this sound, should not be and maybe that is part of the issue?

Anyway, here is the video link - - I hope it gives someone an idea where to look before going the timing chain route.

Thank you all in advance!

 

The only thing I can think off is that the HPFP timing chain timing is off.

wombat

 

Any codes in SDD? Basic OBDII scanner will not give you all the information you need here. The fact that it changes "immediately" upon hitting operating temperature makes me think this is a controls issue and not a mechanical one.

 

I have a pretty sophisticated Autel device (MaxiCOM MK808BT PRO) that can do pretty in depth scanning. However, if you think that SDD would give me even more information then I would try to get that and do the scan.

However, to me what you say makes sense. I mean, why would the pressure be low when the engine is cold and warming up and then jump to way too high the moment it reaches normal operating temperature? The pumps are mechanical by nature driven by the shaft so their output should not change based on temperature as they rotate the same way whether the engine is cold or hot. At least, this seems logical to me.

Also, when the engine comes to temperature you can hear a very distinct change in pitch that comes from the general direction of where the pumps are and it is higher, like they are operating harder which would also be logical that now the pressure increased. One time, I left the engine in the restricted mode all the way it reached the normal temperature and nothing changed but the moment I cleared the codes, the pitch changed and the pumps started outputting much higher pressure. This makes me think that something in the car's electronics dictates this. in particular I believe that both pumps have a build in pressure regulator that is driven by the 12V connector connected to them. If the signal is wrong maybe the regulator let's way too much pressure than it should?

I will conduct this experiment today one more time by starting cold and seeing if the pressure changes only when I reset the codes or if it goes by itself when the engine reaches normal operating temp.

However, if that is the electronics that does this, where would I go next? Is it the ECM that is broken or something else? Is there some hard reset that I could do either to ECM or other modules?

Thank you again!

 

The ECM controls the output from the high pressure fuel pumps. Although the pumps are cam/chain driven, the electrical connector on the pressure relief/recirc valve on the high pressure fuel pumps is fed signal by the ECM to control output volume of the pumps. This is in a closed loop with the fuel rail pressure sensor to balance fuel pump output, injector latency, and requested engine load. The fact that you replaced the fuel pumps and have the same issue could help eliminate the fuel pumps being an issue unless the chain timing is off. That's not unheard of, especially in the early model years. Checking the timing is relatively non-invasive compared to the actual adjustment procedure- take a look at the workshop manual.

The reason it idles well in Restricted Performance load is because that closed loop is opened and the ECM switches to low pressure fueling tables, fueling not off the high pressure capability of the pumps, but only on the ~30psi that the electric in-tank pump generates.

Before Restricted Performance is triggered, do you notice any symptoms that you are flooding the cylinders with fuel? Since it eventually runs "well", I would not expect this. Have injectors ever been replaced (counterfeit risk)? When you replaced the fuel rail pressure sensor, was it OEM or aftermarket?

 

Thank you for all the insightful information! It's good to have a better understanding on how the ECM works in conjugation with other sensors and also what the Restricted Performance actually does!

I know that the injectors have been recently replaced by the previous owner but I do not have access to that invoice to know if they were OEM or not. The fuel pressure sensor was not actually replaced. I bought an aftermarket one for cheap to see but when the symptoms were exactly the same I assumed that it is not the sensor so I switched it back to the original which is OEM.

To answer your other question... when the car is first started cold, it idles really rough with RPMs going down to almost it dying as the battery light comes on. However, it somehow manages to stay on and in about 10-20 seconds the restricted mode triggers making it all better (like stated above). I have the fuel pressure on my obd scanner on display and I see it being very low so I'd assume that the engine is not being flooded with fuel as there is simply not enough pressure. I actually sometimes (not always) get the misfire codes on that initial start. This also tells me that it most likely is because it is starved of fuel and not the other way around. However, maybe I'm wrong what I assume here but these are the symptoms and therefore my conclusions but please correct me if I'm wrong to assume so.

I think checking the timing is fairly simple as I just have to get to to front of the block where the pumps are connected. However, I'm assuming that the engine has to be in top dead center (TDC) for it to be checked properly. I'm not sure if that's true. If so, do you know how to do that?

Also, I don't have access to the workshop manual. Do you know if I can download one from the internet or do I need to buy one?

Thank you again!

 

puzon 23,

The HPFPs run off a separate timing chain independent from the main timing chain. If the engine has ever been rotated backwards, for any reason, there is a strong chance that the HPTP chain will have jumped a cog.

To test this you remove the vacuum pump on the front of the engine and insert a special tool. If the tool goes all the way in, and aligns with the HPFP camshaft, the timing is set. If not, the only way to adjust the HPFP chain is by pulling the front cover off the engine.

wombat

 

Thank you for the info! From your description it does not sound like I need to do anything with TDC? Simply open the vacuum pump and insert the tool no matter position of the cylinders? It might be a silly question but do I have to worry about loosing any oil when I remove the pump?

 

This could be a clue. Bosch-branded direct injectors have a bad rate of counterfeit parts right now. Some of the counterfeits are really good and look almost exactly like a Genuine Bosch part, but end up causing hard-to-trace problems. RockAuto, Bosch-authorized resellers and the dealership are the only reliable places to get these injectors new for about $90 apiece. I would never buy used or Bosch-branded injectors off Amazon or Ebay.

I am also suspicious of the injectors being "recently replaced". Did the previous owner replace the injectors to treat a pre-existing condition by throwing parts at the problem? Did they replace with Genuine Bosch injectors? If they were replaced, did they do it correctly with new Teflon seals properly installed? Is there a very strong eggy or sulfuric smell out of the exhaust when it is poorly idling when cold? I mean a way worse, more pungent smell than the slight rich smell you always get from a cold start enrichment cycle.

I would check the HPFP timing as a next step. In terms of difficulty it's much easier than removing all the fiberglass firewall cladding and then pulling the injectors.

 

The only workshop manual that's freely/easily accessible is the 2010 XFR Workshop manual available from several sources on Google. That should be the identical procedure to your XJ.

 

Thank you all for the replies! I should get the tool tomorrow so I should be able to get to removing the vacuum pump shortly after and fitting in the tool to see. I still need to find the manual to check if I need TDC. Thank you all!

 

Yes, if you don't drain the oil, at least a couple of quarts, oil will come out when you remove the vacuum pump.

 

The engine does not need to be set to any specific position to check the HPFP timing. If you are removing the vacuum pump, I would suggest that you replace the 'O' ring on the pump before refitting.

wombat

 

Great advice. If the vacuum pump seals are still original factory seals and it isn't leaking yet, it will be.

And it's not just a single seal on the vacuum pump, there are a few.
You can get a kit like this
RKX VACUUM PUMP REBUILD SEAL KIT for Jaguar Land Rover 5.0L V1 LR4 RR superchrgd | eBay
or
Vacuum Pump Rebuild Seal Kit For Land Rover LR4 Range Rover/Range Rover Sport | eBay
to refresh the vacuum pump seals.

 

Thank you all for replies and advice! I have one question here. I'm not sure if I understand how I can check the timing of the pump without putting the motor in TDC?

I mean, couldn't I simply keep turning the crank until I get it to such a position that the tool would simply fit? This would make the check not very useful.

Whereas, if I have it in TDC then I know everything is lined up correctly and if the tool does not fit then, I have a timing problem? Can someone explain please?

 

The HPFP timing is independent of the main engine timing. You could turn the engine to though every degree until next Wednesday and it would not mater. There are alignment marks on the HPFP cam and chain that must be aligned.

wombat

If the HPFP tool doesn't fit correctly, the HPFP timing is out.

 

Quick update on my "adventure" with the high pressure fuel pumps. So I took the vacuum pump out to fit the tool and it is out of time. However, quick info for anyone who would also be in a similar boat. You certainly CAN turn the crankshaft the way that the tool will fit. I did that and I have a picture showing exactly that (see below). However, afterwards I put the car in TDC (top dead center) and the tool did not fit at all so now I know that I have to do the timing, sigh...

Question, is there some way to be able to adjust the timing of just the fuel pumps without doing all the chains? I have a feeling that it won't be possible but wanted to ask just in case...

 

Great picture!
Do you have a part number and price for the tool? I did know about the tool but had never seen it in use.
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Ouch. Since your valve covers will be off, good time to change the valve cover gaskets as well as the plastic cooling system components and water pump at the same time as the timing chains. Think of it this way, you'll be bulletproofing this car for the next 100K miles.

 

The engine must not be set at TDC. The flywheel timing tool must be inserted with the crankshaft in the correct position which does not give you TDC on number 1 cylinder - its close but not quite there. One also has to remember that the crank turns through 720 degrees for each power cycle so one must fit the tool with the crank at the correct phase of the cycle. In other words approaching TDC with inlet and exhaust valves closed. (the crankshaft/crank pulley woodruff key must be at the 6 o'clock position) Only then can you check the fuel pump timing.

I cant answer about adjusting the fuel pump timing. It all depends on whether the fuel pump chain tensioner can be moved enough to give the chain enough slack to jump the teeth. But make sure you have the flywheel timing tool inserted correctly first before you do any more dismantling.