Practically no power after coming home from work (thankfully on the last street 0.0).

When I reached a stop sign, my RPMs were sputtering from 400-650ish (got on video) and the car was thrashing a whole ton front and back. It was more bizarre than anything. Car barely wants to stay on when I do start it now, and it sounds terrible. Worse RPM sputtering than before, when I was coming home from work - albeit that is because the car was already warm.

I just threw some SeaFoam into the gas tank to let sit for a while to do whatever it does. Injector flush is what I was looking for. Cleaned the MAF sensors and reinstalled them. Have yet to turn the car back on - but figured I would make a post on the internet's greatest resource while I had the chance. Also as a pre-req in the case I get stopped from messing something up.


update***
Got a scanner, scanned the CEL & the device hit me with "P00C6 &

 

^^^^^ and of course, I accidentally post the thread without finishing. my apologies, as I cannot edit it seems. I will continue the post here!

P0506" with the phrases "Fuel tail pressure too low, engine cranking, bank 1" and "Idle air control RPMs lower than expected" respectively.

After -very- minimal, albeit time consuming research, because I can't seem to find my answer, I stumble upon something that points me in a direction. Many past thread creators would just replace a fuel pump, and it would solve problems as a majority. I see threads here and there about there not being a serviceable fuel filter - meaning there is only a filter in the gas tank; the opening being from under the back seats. No problem, except that's where HPFP (high pressure fuel pump) of course, comes out of the woodwork and confuses me further. Are there 3 fuel pumps?? 1 in the tank, which is low pressure, shoots gas into the camshaft's (2) fuel pumps that are high pressure? also known as engine mounted fuel pump? should be 410-430PSI type of pressure up there, if I read correctly.

I search up in the fuel/air section on RockAuto and notice A. there isn't even a fuel filter option, which should have explained most of my confusion, and B. there are only 2 types of fuel pump listed on the site. 1 is electric, and $150. the other is $350, and 'mechanical'. I would assume that the latter is the engine-mounted 'HPFP' and the first being the fuel tank fuel pump.

Big thanks to anyone reading through this, I am lost and don't think I can continue without some guidance.

 

SNAPCHAT, you have the correct basic idea, you have an electric pump in the fuel tank that transfers fuel from the tank, up to the engine. THis is all low pressure (like 40-50 psig).. You are correct in that there is a cloth filter over the end of the suction so the electric fuel pump doesn't suck up any large chunks. This low pressure line feeds 2 engine driven high pressure fuel pumps that can provide fuel pressures up to a few thousand psig. Now, keep in mind that I am assuming you are talking about a 5.0L engine. The 3.0L engine should be very similar, but I am not familiar with that engine. The high pressure fuel pumps are mounted on the under side of the engine on the passenger side of the engine (assuming you are driving a left hand drive vehicle). The high pressure fuel pumps are not super hard to replace, but you don't have a lot of room to work though too. I did it myself and I have "bear claws" for hands. But, I also have a fair assortment of tools too. Keep in mind that you also have to consider that the fuel pressure sensor that can be causing issues. So, a ittle bit of investigation needs to be done to feel out what the problems could be.

Not to scare you, but I recently had a similar issue. IN my case, I had taken the car in to have a water pump replaced. The shop replaced the water pump, but the car ran like hell afterwards (barely ran). I was getting codes relating to low fuel rail pressure, issue with the high pressure fuel pressure sensor, and misfires on numerous cylinders. I replaced the pressure sensor (no improvement), I then replaced both high pressure fuel pumps (slight improvement, but still ran like hell). At this point, I figured I was pretty much left with a failed fuel injector. Low and behold, I had a failed injector. After new injectors were installed, the car ran like a champ. So, may need to keep a little bit more open mind as to what is going on.

 

I'm impressed and happy to see the amount of reading & research you've done to this point, I admit I was put-off by the name SNAPCHAT (not a fan), not that there's anything wrong with it - just personal bias...

BUT anyway, my wife's XJ had the same thing happen a few months ago. In that case it was the HPFPs.
One thing that was interesting was that after it sat & cooled completely, it would start & run normally, until engine temps got to normal operating temps.
Then it would progressively get rough to the point of stalling, until it cooled-off (ambient) again.
It ran fine for her at highway speeds when it failed, until she pulled-off for a break, Then it ran as you described, so she shut it down & called me.
When I got there, it'd run alright for a little bit, for me to move it to a better parking spot for the tow truck.

I did post the experience in this forum a few months ago that included some helpful input at the time.
I was fortunate that my injectors were/are fine, but I also periodically run Lucas injector cleaner through it as normal upkeep.

I think you got the Rock Auto prices mixed-up, the in-tank LPFP cost more than the 2 HPFPs, IIRC I paid around $150 each for them.

 

Without any car info how do we know if he is talking about an XJ?
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Thank you both for your replies @Thermo @12jagmark !!!!

​​Very helpful insight you have both provided. I am not very mechanically inclined (if either of you need help with a computer - I am your man) and this is a super spontaneous learn-as-I-go moment; apologies if I ask a repetitious question or 3!

I have tools, I can get most of whatever job done that isn't absolutely ridiculous. YouTube tutorials go a long ways, but as we all know, Jaguar content online is fairly skimpy in comparison to any other manufacturer. We signed up for it 😂

As for the HPFP, could either of you 2 confirm which of these is the correct pump? I attached an image on this reply pertaining to the RockAuto choices. Are these both HPFP? Is one of them the fuel tank pump? Again, thank you for the insight. I have been walking 4.5miles to and from work everyday for a little over a week and just want to purchase the right stuff to make this work again!!

Is the job insanely hard? Is there anything either of you will advise of before I order these and mentally prep for the job? Or is it going to be as easy as rolling my car onto some home depot ramps and swapping out a part or 2?

@clubairth1 I filled out my profile information and added my cars make/model/year - thought the information would stand out or something - new here! sorry!
also I am pretty sure this is in the x351 threadgroup so at least that's right.


​​​​​​​2012 XJ Supercharged 75k miles

 

Ah - yes, I see where the confusion comes, and sorry for not thinking deeper into the scenario...
The 3 under "FUEL PUMP" are all HPFPs. I now guess that you got the >$300 price for the HPFP from the Delphi pump price, but assumed the LPFP is the Bosch pump.
Not the case. Both of those are HPFPs, but with Bosch being the JLR OEM supplier and as good quality as Delphi from my experience, I bought the Bosch pumps (2 of 'em) @ ~$150/each.

If you're looking for the LPFP (the one in the tank), you need to expand the "FUEL PUMP & HOUSING" selection, where you'll find it in the >$500 range (IIRC).

While I was intimidated at first with the HPFP replacement, I found it to not be so challenging.

I suggest you look for the JLR TOPIx website, and create an account (as an individual, not a retailer or dealer), where you can subscribe to the whole arsenal of JLR-genuine resources that is available and used by the actual dealers, and indy repair shops that find it worth subscribing to.
Navigating the website isn't as intuitive as most would like, but it is British (maybe more Indian now), so you may need to hunt around it for a while.
From there, you have access to the tech manuals and the JLR SDD system that the dealerships use for "Symptom-Driven Diagnosis" that connect to the vehicle for service, diagnostics, adjustments, etc..
To make it easier to work with the TOPIx tech manuals, it may help if you print the section(s) you're working to PPT files, to be available off-line where/when you're working it.
That tech manual includes full description of each system, remove/replace of each component, and schematics.

There is an Adobe PPT version of the JLR tech manual in a stickie, but all I've seen available is for the 3.0 turbo diesel, which crosses over to ours mostly, other than engine-related stuff.
I find myself subscribing to the JLR TOPIx as needed, for the 'real deal' that applies to my VIN, for my wife's Jag or my 2 Land Rover Range Rovers. I'm thankful that it's made available to us, and the subscription rates are reasonable to me (be it daily, weekly, monthly or yearly (never have subscribed yearly yet though).

As far as the job, it's not hard for a moderate wrench-turner. Modern (Ford-era and later) JLR vehicles seem to be largely reparable with 10mm and 13mm wrenches, Torx bits & screw drivers, with a few additional tools for more in-depth things.
The best reference is the TOPIx R&R instructions (although more pictographs than text), and search X351 threads, maybe Youtube (I hate to suggest them generally) videos for tips/help.

Advice I (and others) have found is that where JLR says to replace the HPFP fuel line, not needed (in my case and others I've read). Make sure that the shims between the pump & can that drives them stays in there, or is put back in if they do come out when you remove the pump.
I removed the alternator when I did mine, to free-up the HPFP fuel line that runs under it from the pumps to the fuel rails. Easy enough & worth the effort to me. But I think some others didn't & were okay with that.

Search & read, and you'll find info on the process - much more efficient (and GREENER!) than having us re-create the whole experience(s) again in this specific post.
You need to remove the undertray that covers under the engine, get the car up on ramps or SECURELY lifted up enough to get under it. I drove it up on a set of very sturdy ramps that I bought at Harbor Freight.

You can find some detail here, but if you search you can find more.

Have any of you replaced the HPFPs yourself? - Jaguar Forums - Jaguar Enthusiasts Forum

 

SNAPCHAT, one thing that I have not seen is you do need to remove about half of the oil from your engine when doing this. The pumps sit in the oil pan and if you don't lower the oil level manually, it will lower itself for you when you get the high pressure fuel pumps loose. Like was mentioned, yes, Jaguar says you should replace the fuel lines. No need for that. Just don't go crazy with tightening them. Getting them snug is all you need. I also found getting the sound insulation back on the fuel pumps to be a little bit of a challenge as you have to have the insulation on the piping when tightening everythign up so that the insulation stays.

Do the one that you can reach easiest, then do the other, install the new pump where you removed the second pump from and work your way out. Otherwise, going to be a bit PITA. How do I know?.........

 

VERY good catch - I failed to mention draining some oil.
You can drain it the old-fashioned way with the belly pan off, by the oil pan drain plug or by suction from the oil cap tube.
I know you mentioned you're not very mechanical, so if you're too intimidated by it, it may be worth getting an estimate (and that's considering that you're still not 100% sure what specifically it is). It will not be cheap.
BUT it does not take a master mechanic, it isn't quite as challenging if you are reasonably good at doing your own general tasks such as brakes, oil changes, other mechanical tasks.
When I work on my 2012 RR or the wife's 2012 XJ, I sometimes get the feeling that they were not only designed to be driven, but also designed to be worked on too. Like I said, it seems like 90% of the bolts are either 10mm or 13mm, with a few 15mms thrown in there for heavy-duty attachments.

By the way, if you do get down under your XJ, take a look at the vacuum pump at the front of the engine & see if it's leaking oil down there.
Pretty common source of oil leak after 8-10 years, and easy to access while you're there.
It's driven by the same cam as the HPFPs, and also needs the oil drained a certain amount or it'll pour out when the vacuum pump is removed.
Search the Forum for vacuum pump - related posts, that describe the details. The oil seal between the pump & the block can be replaced pretty easily, and sometimes an o-ring where the vacuum tube connects to the pump needs to be replaced too (if leaking). Two Torx bit screws hold the pump to the front of the engine.

I assume that all this being thrown at you \may be intimidating, but if you're a Comp Sci person, it's probably not beyond your technical capability.

 

Today I got one of my fuel pumps in the mail.
Raised the car, removed the passenger front tire, and got to looking around. Am a bit more familiar with what I am looking at now, as I stared at everything for a solid 2 hours before I turned a single wrench lol.

I noticed the #2 HPFP is noticeably easier to remove and replace than #1 is - there is a metal plate covering the fuel line from being removed. That is somehow where I ended up getting stuck, right at the beginning.
I didn't and am not going to consider removing my alternator as I would be delving into waters I am way not comfortable with - and I know that I can get the plate/fuel line cap (the one that you aren't supposed to tighten super tight) removed from the #1 fuel pump.
My current issue is removing the bigger 9/16 socket bolt that is holding it in place. There is a much smaller bolt on the other side (pictured in blue) that I was able to easily remove - but the big bolt would just not budge. Going to go to a parts store and purchase
some more tools (angle wrench) so I can actually get that guy out. After I get that cover off, should I remove the fuel line from the fuel pump, and then the 2 smaller bolts holding the pump onto the cam? You guys are saying that half of my oil will drain out once I remove
the pump, which is fine & I'll get that handled - I am just worried about removing the fuel line from the pump, lol! I don't want anything exploding on me as I slowly turn that silver cap.

 

Well as you loosen the connections at the HPFPs, any residual pressure and fuel in the lines would bleed-off, so just loosen until fuel begins to come out, (with paper towels or burnable rags to catch the fuel) and let it there until it stops, then continue to disconnect the pipes after it stops. BUT as long as you disconnect the (neg side of) the battery and let the vehicle site for a while (15 minutes, an hour...), the pressure will settle out by itself.

In my case I removed the alternator (and maybe the belt idler pulley too IIRC) just because they're easy to remove, and I know I'll need to R&R the alternator at some point anyway. Our XJ just passed 150k miles, so the alternator is on the list of things to refresh, to avoid another break-down situation for my wife, as well as she handles them.

BUT since you'll be working near your alternator connections, especially with fuel, DISCONNECT YOUR BATTERY - the neg cable anyway.

The 10mm bolts that hold either of the HPFPs on aren't difficult to reach, for the one closest to the motor mount, I just used my small 1/4 drive ratchet & socket that fit in there fine.
Did you already take the acoustic covers off of the HPFPs?
I had no problem removing/installing the HPFPs with the foam covers in place, just moved to give access to the pipe fittings.
And yes, first remove that cover plate, the disconnect the inlet & outlet pipes (no need to completely remove them), then remove the HPFPs.
I also loosened or disconnected the fuel line at the top, where it connects to the fuel rail at the front of the valve cover, to make it easier to shift the fuel line around without bending/damaging it & to relieve any residual pressure (with rag wrapped around the junction).

And it's well worth draining at least a couple quarts of oil prior to removing the HPFPs. Since you're under there, the oil pan drain bolt is right there. If you just let the oil drain when you pull the HPFPs, the cam "bucket" / shim will likely come out too, so there's a risk of forgetting to re-lube it & put it back in before attaching the HPFPs if you don't not to mention the additional mess. But it's your call of course.

 

Thank you for the info. Was going to get setup to start working on it today at around 5pm; started a jaunt toward my car and tried opening my trunk. No deal. No biggie, I'll find the keyslot that's somewhere on the back of the bumper, since all of our fobs come with a blade for instances like thisNo deal. Okay, surely I can gain access to the trunk from inside the cabin and pull a latch or maybe just gain access entirely!? No deal. Practically a firewall blocking every square inch of the behind of the rear seats, except for the middle. Awesome. Just fantastic!!

Trunk module is completely electronic and has absolutely 0 mechanical mechanisms (aside from the emergency latch, which is in an impossible spot & on the inside of the trunk) to use to open the trunk. I removed the negative battery terminal from the battery as I was working on fuel pumps yesterday - and shut the lid because I surely didn't think anything like this could happen. I threw ALL of my tools in my trunk & the jacks/jackstands so I can't even make progress on my fuel pump. I live 3+ hours from nearest bag dealer. Luck on luck on luck lately. Almost can't take it lol.

There is a 12v positive terminal & a ground that I supposedly can connect jumper cables to in the engine bay, to supply just enough electricity to open the trunk? Risk of blowing a fuse within the fusebox but I am willing to do anything at this point.

​​​​​

 

12jagmark 150K miles on your XJ is very nice to see!

With the negative battery cable disconnected how can you open the trunk?
We do have a sticky on this problem but you probably have already read that?
If not take a look;
Get Trunk Open with Battery Disconnected

There is a connector you can access after removing the rear seat bottom and folding the rear seat back down. This should work even if the battery is disconnected like you have done. Do you know how to remove the lower rear seat cushion? There are 4 clips that must be released and they are hard to get to for me.
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Connected a 12v+ to my fusebox prong & a 12v- to an unpainted ground in the engine bay.

Fob in hand, I spam-press my trunk release button hoping there was enough electricity to pop the latch - to my surprise, the whole rear-end of the car lit up & I heard a click!

Trunk latch opened instantly, but didn't have enough power to open all the way up - but it was open nonetheless. Several forums of XF drivers 2015+ not being successful doing the same thing. If there are any XJ owners out there (2012 area) and you come across this post - try the fusebox method. I had my back seats completely ripped out & I was ready to go through the firewall to get the trunk open. Pic attached to give instruction.

 

Update.

Got that metal cover that guards the #1 fuel lines off. Got both of the old fuel pumps off. Installed the 2 fuel pumps I received. Put in 7.7 quarts of oil. Got a jump on my battery so it would have enough juice for the grand finale.

I sit down in the Jag, take a deep breathe in and out. This is my only hope to be able to make it to work for another week without having to walk or bum rides. I press the ignition to see the codes and what my dashboard says - all looks normal and checks out.
I hold the ignition button. Starter whirls for a bit longer than normal (albeit) and she fires up. Perfect RPM, normal sounding noises, & no thrashing front to back. This is the part where my girlfriend notices a gas smell. "Smells like gas". Sounded quite normal to me, considering the job that I had just completed.
I take a gaze down underneath to see what all of the fuss is about - gas is just dripping everywhere. Tons of it - car still running and sounding normal (?) but gas is just everflowing from out under. Kind of in a downer mood right now and not totally feeling getting back underneath tonight (5-6 hours just today) to look
and see further where the gas is coming from. Didn't know if there would be any obvious blatant mishaps people come across whilst doing such a job.

Continuous thanks in advance no matter what - if anyone knows or has any idea as to what this could mean or what could be causing it, please. Thank you.

 

Rule of thumb - always check as much as you can before firing up.
The LP side of the fuel system can be checked without starting it up, since it's an electric pump that turns on when you open the door.
However to cheek the HP lines, it does need to be running.
Next rule of thumb - fire-up and check for leaks prior to putting covers on. and in this case, let it heat-up to full operating temp before putting the covers on since it could run fine until it heats up.

But the good news is that it's one of the connections that you touched, so it should be easy to find (you probably already have by now), and just needs to be fastened correctly. Hopefully no biggy and easily corrected.

 

Success!

-Refastened the high pressure fuel pump connector that connects to the fuel rail (line?) ((metal socket)) a tiny bit harder than I previously had. Read your remarks about tightening the lines a little too hard - was absolutely not going to let that happen.
That also happened to be my blunder.

I figured it had to of been a bigger issue with how much gas was coming out (I seriously cant put into words how much it was) but alas it was simple. Curse lifted.
Bought these 2 pumps from a wrecked Land Rover from eBay for $107 each. Each pump has 12,000 miles on them.

@Thermo @12jagmark Round on me, thank you!

 

i'm kinda surprised i can't find any diagrams online that clearly show where the 2012 fuel pump relay is located in the fuse/relay box. Can anyone point me to a diagram or imaged posted anywhere which shows which relay is for the pump?
Thanks.