Hi Gents,

I'm trying to run down a problem that I am having with the XFR sputtering around 5800 - 6200 RPM. It has only intermittently thrown the P0087 code (Fuel rail/System Pressure - too low). So far I have changed the "in-tank" fuel pump and have a new fuel pressure sensor waiting to be installed. I am logging the car with Torque Pro and it shows the Fuel rail pressure at 525 - 550 PSI range at around 6000 RPM (WOT). This seems very low and was curious what the correct pressure should be? Currently, at start-up, it is fine at 2100 PSI and I believe the idle is in the 500-600 psi range.

 

At 6K mine sits around 2200psi. I have read about a fuel pump housing shorting issue that makes the car sputter. The housing pins is the culprit-https://www.youtube.com/watch?v=U3yaYvYJZu4

 

Thank you for the reply. I just replaced the flange (the pins were burnt on prior flange) and the in-tank fuel pump. My next logical guess is the pressure sensor

 

It cannot be the in-tank pump because that only primes the system and starts the engine. The 2200psi pump is off the camshaft and the crankshaft If the workshop manual I read was correct. I would think TPS sensor or one or both of the MAF sensor that are known to go bad that would cause that. Try cleaning the MAF's and see if that helps

 

Thank you for the reply. I just replaced the flange (the pins were burnt on prior flange) and the in-tank fuel pump. My next logical guess is the pressure sensor.

 

Correct, the two high pressure pumps are cam driven off the block. I replaced both MAFs before I replaced the in-take pump. The TPS sensor might be a good place to look.

 

Do you notice what the AFR ratio is when this is happening? The Jag doctor told me fuel injectors were common to lock open at high rpm due to age and high pressures over time. If you knew if it was running rich or lean it would tell a better story. Also you probably have but have you checked your spark plugs and coil packs? If there was no spark in a cylinder it would be have a rich AFR and misfire which would tell the computer to pull back the pump pressure.

 

I have logged about 5 - 8 runs and the AFR is spot on. The only out-of-the-ordinary readings are coming from low fuel pressure and low boost (max of 6-7 PSI at WOT)The car hasn't thrown any codes yet even though it sputters around 6k RPM. I just found an old thread about this same scenario which points to replacing the high pressure fuel pumps. My assumption is that they can be reached from underneath and hopefully without too much difficulty. I'm going to check the voltages on the fuel pressure sensor and if they check out, move onto the pumps.

 

Here was that older thread that details my same scenario - https://www.jaguarforums.com/forum/x...00-rpm-168544/