Hi all,I got a 2015 Land Rover Range Rover 5.0 Supercharged from auction with a fuel pressure issue.

The car has cylinder 5-8 misfire(both banks!) and fuel rail pressure too low errors.


Carfax shows the injection fuel pump was recently replaced (likely HPFP).

Using SDD, I get:

• Low-pressure sensor: 2.5V (normal)
• Fuel rail pressure sensor: 0V (abnormal)

I replaced the rail pressure sensor and checked the wiring. Pin 5 on the sensor receives 5V. Pin 3 (ground)seems to be good. Was even trying to ground it straight to body.
When check Voltage on pin 4(pressure output) it shows 0.5v when engine off ignition on. When start engine it goes up to 1.5-1.7 in voltmeter, but sdd sometimes shows 0, 0.5, 1.7V. Very inconsistent.

ECU seems to be replaced, found in the trunk the old one.

Anyone seen this before? Could something like the fuel pump driver module or a grounding issue be frying ECUs?


Cleared all errors. Started car, noises from top, sounds like camshaft sprockets are
Trying to adjust timing for first 1 sec running.

here are current errors:
U0011-82 High speed CAN communication bus

P00C6-00 Fuel rail pressure too low - Engine cranking

U0011-82 High speed CAN communication bus

P131A-00 J_ 14229_DTC_P131A

P0088-85 Fuel rail/system pressure - too high

P053F-23 J_14229_DT_ P053F

 

Please check the battery. These cars are power hungry and if the batter is weak, you will get all kinds of warnings and messages. Also, make sure the ground is good.

 

Update:
Bought timing tools. Put the flywheel lock(I assume the is only 1 way to fit it). Removed the vacuum pump, and it seems the hpfp timing is completely off, about 90%. I probably can time it back, but really want to know what made it jump 90 degree. Any thoughts?

the numbers and weird communication errors were most likely due to battery. But the misfire issue seems to be caused by the chain.

 

It’s been about a week, so I wanted to share what’s been done and where things stand.

I set the timing for the HPFP as accurately as I could. The timing tool doesn’t fit perfectly, most likely because the chain is slightly stretched - but it’s very close.

I installed the lower timing cover and a new vacuum pump. I struggled a bit with the crank pulley. Using a Chinese tool, I pressed it onto the crankshaft - not entirely sure if it’s seated deep enough, but visually it looks fine. I installed a new crank bolt and torqued it to 200 Nm.

As per the procedure, I attempted the additional 270° turn. However, I could only manage about 90° before the breaker bar with a jack pipe started bending badly, and it wouldn’t go further. I didn’t want to risk snapping the bolt, so I stopped there. I marked the bolt and will monitor it over time to make sure it doesn’t loosen.

After reassembling all the pulleys and other components, I started the engine. It runs, and I’m no longer seeing any fuel pressure codes. At first, it was misfiring heavily, but after running for a bit, it improved. Right now, there’s still a slight misfire. The codes don’t appear immediately, but after about 30 miles of driving, I got cylinder 5 and 7 misfire codes, along with a random misfire.

I swapped plugs and coils - the misfire follows the components, but it keeps returning to cylinder 5 consistently. Then I swapped the injectors between cylinders 5 and 6. After that, I began getting misfires on both 5 and 6, and the symptoms worsened.

I did a leak-down test using an OTC tool. Cylinder 5 shows about 95%, while the others are slightly better. The engine was cold during the test.

I’m now waiting on a new set of injectors for bank 2 (cylinders 5–8) and will post another update once they’re installed.

I’ve checked the oil filter a couple of times, no metal found so far, and the oil no longer smells like fuel.

One last note: during the leak-down test, I could feel and hear air coming from the oil fill cap, even though the gauge showed only about 5% leakage. Is that normal?