Nissan Repair: Excessive gasoline usage, fuel pressure regulator, gasoline usage

Question
QUESTION: I recently purchased a 2003 Nissan Skyline 250gt. I recently fill the tank and I have only done 250 kilometer about 150 miles easy driving and I have less than 1/4 tank of gas in the vehicle. I this normal?

ANSWER: Lancelot,

Check the fuel pressure regulator as it is probably blown causing excessive fuel consumption.  Also, if the vacuum line is off the fuel pressure regulator or the line is cracked you will experience excessive fuel consumption.  Now, if yours only has one line to the injector rail then the fuel pump is where you will be starting since they moved the fuel pressure regulator to the fuel tank where it is an integral part of the fuel pump assembly.

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QUESTION: Where is the fuel pressure regulator located? Does this mean that the fuel is blowing onto the road?

Answer
Lancelot,

The fuel pressure regulator is most probably in the gas tank as part of the pump assembly.  What is going on is the fuel pressure is more than it needs to be.  The injectors do their job and with extra pressure you use more gas.  The engine will not complain but the mileage will be less.  I would have the fuel pressure checked by a shop to verify my on-line diagnosis.  One other cause would be leaky injectors and that too could be diagnosed by checking the fuel pressure.  Key on and then off for this one checking for leakdown.