Howdy folks. I’ve had quite the run around with my 2011 XF 5.0 SC. I’ve been having some difficulties lately with fueling issues and could use some advice, pointers, or just the next place to check.
To bring you up to speed:
Timing Chains (not Fuel Pump chains just yet), SC snout rebuilt and ported along with TB, Mina Lower Pulley, stock upper (Minas didn’t work first try at 575F), Mina Intake Tube with MAF tubes and K&N filters (washed the oil out), belt and tensioner on SC, ZZP Charge Pump all done Jan-Feb 2022.
So after all my work I get it running and everything was good until I decided to do the Trans service with- ZF fluid, filter, bridge seal, tube seals and the mechatronic sleeve. Had difficulty with it not wanting to leave park (low fluid turns out) and threw a TON of codes (mechatronic sleeve wasn’t seated 100% thus not allowing Mech plug outside to meet Mechatronic inside). But Hidden amongst them was a lean code bank 1. I Checked Fuel Trims to find STFT bank 1 exceeded +20%.. way up there. I took a listen to the injectors and found 5/7 were sounding quite different. Removed them and noticed at some point the seals had gotten nicked pretty good and decided to replaced their Teflon seals. After I did this, I started to run Live Data every time I got in to drive the car. Watching mainly Fueling and Temps. I started noticing the Fuel Rail Pressure actual didn’t match the Desired at almost any point in time and my Fuel Pump Duty cycle fluctuated ONLY between 48% and 52%. Watched Autologics video on the High Pressure System which I believe states fuel pump on signals are between 4%-50% and 75% is off…? I also found that when at idle after engine kicks down the high idle at warm up, I should be evened out around 500psi yet my actual would fluctuate from 900psi down to 230psi and at the low times I would hear what sounded like HPFP being starved like any Power steering pump gets when it’s being ran dry. I found that Neutral at stops brings the Fuel Rail Pressure back to a higher number when it’s low and the sound lessens. So that leads me to the now and I’ve started some more replacements; In Tank Fuel Flange and tank sealing ring, Fuel Rail Sensor (High Pressure) and another round of injector seals. I purchased an in line fuel filter that I thought was in (LHD) driver wheel well but nothing behind inner plastics but a sensor that appears to be connected to lines that are just above driver valve cover. Will be investigating further to try and locate said In Line Filter. I have cleared all Codes and have yet to have anything return (only driven 10ish miles though) I’m almost certain one/ both of HPFP has been compromised as I see the Rail Pressure start to get lower occasionally (but less often and not quite as low as 230psi) and still hear the wine at that time but so far, any time I give throttle it jumps right up to 2100-2200psi as it should.
Many factors to this problem I’ve been faced with. Im wondering, after High Pressure Fuel Pump(s), if the problem persists then should my next move be to check the Fuel Pump Driver Module and every wire related to fueling system?
I’m not sure if this is related but I had some signs of electrical damage at RJB with two ground screws having blackened car paint around them where they are screwed in. Like they got zapped. And I believe I have a parasitic draw, found with + cable connected and - cable disconnected and placing multimeter at - cable and - terminal which is giving me 9ish amps being drawn.
My apologies for such a long post. I’m just trying to include all the background information so anyone who’s knowledgeable in this area could possibly have a full understanding. If there’s anyone with any suggestions or recommendations please feel free to drop a comment or shoot me a message. Anything would be greatly appreciated. I’ve owned the car for about 4 months and have had her road worthy about 1 of those.. Anyways, thanks all for reading. I hope to see any new perspectives. Hope you all have a great day.

 

Saw another post where the Jag tech jsut guessed fuel pump and changed it out and all was well after. I am having a similar issue and changing the pump out soon.

 

I had some odd findings for my situation. I actually had gone through with a tune which if I’m going to be honest, I was a bit disappointed at first. And that was because of some issues I was facing with my tranny shifting and acting all weird and I was getting lean codes no matter what I did. I spent quite a bit of money chasing down this 1000wtq rated transmission build list because if I’m going to touch it I want it to be the last time ever lol and I figured the lean codes had to do with this High pressure being insufficient or the injectors were leaking. I had done 4 sets of injector seals before I caved and basically bought a whole new fueling system (8 OEM injectors, 2 high pressure pumps, 1 tank fuel pump, a tank flange, and fuel rail pressure sensor) not very cheap thing to do.. But the lean codes continued. That is until the last time I touched my injectors, I had my scanner going and noticed my ECU (the new Tuned map) had actually read as a Portfolio. Which if you know, they are NA motors and right then it all made so much sense! ECU wasn’t able to understand that it was being boosted so it just saw all this extra air and threw codes every time the fuel trims had to catch up and exceeded 20%+.
As soon as I brought it up to said tuner, he was very apologetic and had two new maps for me the next day. When I remapped the car to those two new ones, mind you after I had just spent thousands chasing down these symptoms I was having. And buying two transmissions and the rebuild kits for each plus upgraded frictions and what not. All for it to literally disappear with a reflash to a correct tune. $Thousands$ spent for what seems like nothing. And I’m not huge into wasting money but after I had done all the timing and other stuff I wasn’t about to just give up on this car. I tried using diagnostics to figure it out but there isn’t crap about any of the fueling besides a couple videos and one long good one. But none touched on my symptoms per say. So after my re tune, my fuel rail pressure has actually gone to what I’ve heard is a normal behavior. No more 250psi at idles or random drops. Stays fairly consistent. Long story short, if your tuned, check it and ask as many questions as you can because some of these “tuners” pull off a list and what I was told, they don’t notice if it’s incorrect until a customer says something about it.. literally the exact words. Anyways. Hope you or anyone else who reads this is able to learn from my mistakes and experience.

 

so a reflash fixed issue ?

 

Yes and No. those particular symptoms literally vanished with the new Tune/Map. But that only lasted a little. When I reflashed the Tune I also installed the new Mina pulley which went on the first try this time at a higher temp and Came off the very next day when it saw 29ish PSI of boost.. have had problems ever since. So in all, new tune did resolve those exact problems but I’ve been faced with entirely worse ones since. It is unknown if they’re related to the new tune, aftermath of the old one, or just completely unrelated all together. But now the vehicle runs very rough and will throw me Restricted performance and severe driveability issues as soon as it gets up to operating. Every time. Had a **** load of DTCs (105 at first...) Some have been verified to be unrelated. But lots of questions this time around.. no idea where to start. Compression test and checking plugs/ coils, check fluid conditions (oil/trans) and then just reflash to stock and start over or reflash and just start from there..? I’m not very experienced with the proper protocols for diagnostics. I’ve tried SDD but can’t get it to work for ****. But After everything the car and I have been through, tons of new parts and lots of late nights in the garage alone with just a pack of Monsters and dream of having a good running car keeping me going, for it to just **** out on me now would be pretty ****ed up.

 

What tuner are you using?