2004 s40 t5 fuel system issues

rcs3 · Post by **rcs3** » 17 Apr 2010, 23:46

we have a 2004.5 s40 t5 that is beginning to be a major pain in the butt. After the engine has reached operating temperature (and only after this), the engine will lose rpm and generally act like it's not getting enough fuel. When this issue first occurred, you could floor the accelerator and the engine would stumble, come out of it, and then stabilize as though nothing had happened. The check engine light would come on and stay lit for a few weeks, but then go back out. This would only happen every once in a while and it never left us totally stranded. We took it to the dealer who said the code was battery temp sensor. We replaced the switch, along with the rest of the 90,000mile service. The car drove fine for a few more months, and now has gotten much worse. Every time my wife drives the car it jerks and surges violently (after first reaching temperature). Sometimes it dies completely and will not restart for several minutes. On several occasions when it has died, there is no power to the dash instrumentation for several minutes. On any other car the first items I would check would be fuel filter, fuel pump, vapor locking, etc., etc. The dealer assured me that the fuel pump, the pump ecm and everything else is ok. Any thoughts?

Post by **billofdurham** » 19 Apr 2010, 12:01

Welcome to Matthew's Volvo Site.

On several occasions when it has died, there is no power to the dash instrumentation for several minutes.

This would lead me to believe there is a fault in the ignition wiring, possibly at or near the ignition switch.

Bill.

rcs3 · Post by **rcs3** » 19 Apr 2010, 22:41

the dealer said two codes came back- waste gate and fuel pressure sensor. These make a little more sense than battery temperature, although when the problem would occur, it didn't seem like the waste gate was popping prematurely. In fact, the problem starts at an rpm (below 1500) where the intake manifold should still be on a vacuum, not positive pressure, other variables notwithstanding.
They said that the electrical issues can be dealt with with a few software downloads (whatever).
in any case, I'm picking it up tomorrow, $670 later.