2004 V70 2.5T Fuel Problems

lhfabian · Post by **lhfabian** » 23 Jan 2011, 12:45

I own a 2004 V70 2.5T in California and it currently has 154k miles it runs great for the most part except in the last few weeks it seems to stall while driving at regular freeway speeds (65 to 75mph) specially when the cruise control is engaged. I describe the problem as follows, after the car has been running low rpm's or sitting in traffic as one does in th Los Angeles traffic then I start to accelerate it feels like the engine disengages from the transmission on and off. If I stay on the gas and 2500rpm's or higher the problem seems to even out and it runs smooth until the situation is repeated. Problem is sometimes reaching 85+ before it evens out this is not always safe or possible in which case the problem exacerbates until the engine shuts down again not always safe.
the scanner reads the faults P0193 "fuel rail pressure sensor A circuit high input" sometimes a second is P2188 "system too rich at idle bank 1" High fuel pressure. I was advised the problem might be with the fuel regulator but i can't find it either near the fuel rail or the fuel tank area.
So I have a couple of questions one, is there a different suggestion for the problem or secondly does anyone know where the fuel pressure is actually controlled? i would hate to start changing sensor, pump...
I'd appreciate any help,
Luis.

Post by **jimmy57** » 23 Jan 2011, 12:55

That car has a fuel pressure sensor feeding the actual pressure to the ECM. The ECM in turns delivers signaling to the fuel pump module back under car on forward RH edge of fuel tank. The FPM is a transistor amplifier that controls the current to pump to keep it at a speed that keeps pressure with in desired range.
The fuel pressure sensor is stuck in the end of the aluminum fuel rail on engine. Held in by one or two screws. The first code points to it or its wire connector. THe second code is likely the result of the fuel pressure being too high from cause 1.
The sensor can fail and the ECM thinks fuel pressure is 350 kPa but the sensor can be low biased and the actual fuel pressure may be 500 kPa and that causes more fuel to be delivered through injector on each delivery period, it then runs rich at times. The rough running is probably when it is overly rich. The sensor will get a lot hotter when you are idling and could be failing from heat.
You can try FPS and if that doesn't do it (probably will) then it will need to be diagnosed by Dealer or other service shop with VIDA. The ECM values re compared against actual gauged fuel pressure and the signal to FPM can be checked to see if it reasonable for actual fuel pressure.

lhfabian · Post by **lhfabian** » 24 Jan 2011, 09:15

Hello and Thanks Jimmy57,
The way you explain it makes sense to what i understand and the car's behavior. I'm going to invest on a new fuel pressure sensor and hopefully that will solve my problem. I will report back on any change of status on the issue.

dneume · Post by **dneume** » 14 Dec 2019, 08:34

I was getting P0193 codes on my 2006 v70. I replaced the FPS and the engine runs great(no more CEL). FCP Euro has a short video on the steps required to replace the FPS. This is one of the easiest DIY fixes I have performed!