Where is the best place to test for fuel pressure on an m30.?
At the fuel rail?
What should the correct pressure read?
fuel pressure
Moderator: martauto
-
Brianmoooore
- E30 Zone Team Member
- Posts: 49360
- Joined: Mon Jan 10, 2005 11:00 pm
Unless the M30 has a schrader valve on the fuel rail, serving as a test point, which I don't think it has, then you need to disconnect the fuel line from the rail, connect it to a tee piece, then link that to the fuel rail with a short piece of hose. A pressure gauge connected to the tee will give you the fuel pressure.
The pressure release valve is clearly marked with the pressure at which it operates, but the recorded pressure on the gauge will only match that if the throttle is wide open, or the small vacuum reference hose is disconnected from the PRV. With the small hose connected, and at all throttle positions other than wide open, the pressure shown on the gauge will be reduced by the level of vacuum in the inlet manifold.
The pressure release valve is clearly marked with the pressure at which it operates, but the recorded pressure on the gauge will only match that if the throttle is wide open, or the small vacuum reference hose is disconnected from the PRV. With the small hose connected, and at all throttle positions other than wide open, the pressure shown on the gauge will be reduced by the level of vacuum in the inlet manifold.