well - probably not, but here goes anyway. Any insight as to life span or failure rate of the fuel tank breather valve? ('87 325is). Symptoms? Problems if it quits? Can it's demise cause leaning out @ high rpm's? How can you tell if it's dead? aand... while more or less on fuel-related topics, which parts particularly ensure proper fuel pressure is maintained through the rpm range? Presumably in-tank pre-pump, main fuel pump, unclogged fuel filter, fuel rail & injectors - what else? thanks for any info!
Fuel Pressure regulator. Little thing at the front of the fuel rail with a vacuum line running back to the passenger side of the intake manifold.
+1 to Z31. Get a pressure gauge set up on the car and go drive it. Fuel tank breater faiure rate on E30, never seen it happen. If the FPR is intact then the next culprits are the fuel pumps, which have given a very long service.
Remeber you will want to setup your gauge on the line that goes to the BACK of the fuel rail, this is the feed line. Moose can clarify, but it's my understanding the FPR will is at the return end and only opens in small amounts to bleed off excess pressure to keep it in spec. If you were to put the FPR on the return line you'd see really low pressures like 8-10psi vs 38-42psi (but double check that spec against Bentley, not completely sure.
Yes, exactly. There are two lines. The one that comes out right next to the FPR is the return line, and if you put a gauge on that line, it will read nearly no pressure at all. An i runs a 3 bar regulator, and an e runs a 2.5 bar regulator.
