VersaTune User Forum

My fuel pressure dropped at WOT so I updated the high pressure fuel pump internals (from PTP in this case). Now especially by redline on 3rd fuel pressure oscillates much and spikes over 2000 psi or 13,8 MPa. I think this is not good for recirculation valve or how is that called.

I'm running 98 EU Octane high load map where max. seems to be 12,4 MPa.

Should I try stock settings in all those 5 fuel pressure tables? Max setting would be somewhat lower there (11,5 MPa).

Are you using the stage 1 or stage 2 pump?

If you are seeing values over the stock relief valve pressure, reduce the targets to stock values and log again. If they are still too high after that, you may need to port the spill valve in the pump.

Thanks guys. I have just the internals so stage 1 I assume. I'll try with stock values and have a look. Winter is coming, today -5C and first snow expected.

Sometimes the relief valve starts to get weak, I have mine pressure set to 1680psi. If you are running more pressure than it can hold, the valve cracks open and you can get those wild pressure changes.

whats the crack pressure on the reilef valve?

1885psi, I think.

1850psi, but mine starts around 1820psi so I try to keep it under that.

The set pressure should be at least 50-75 PSI below the RV open pressure. The HPFP does not hold pressure exactly at the set pressure, so you want to give it some room to fluctuate. If you are opening the RV all the time, you will wear it out prematurely.

I have now tried with stock pressure setpoints but it does not help, pressure still peaks over 2000 psi. Today I opened and cleaned the spill valve, let's see.