Fuel preasure question
Thread Starter
Instructor
Joined: Mar 2003
Posts: 228
Likes: 7
From: Navarre fl
Fuel preasure question
I checked my FP I have 38psi at idle, 40psi WOT shut down it's at 42psi. We had some snow and I had the car running to warm up and noticed that the snow was black behind the exaust do I need more or less FP....Thanks
Burning Brakes
Joined: Feb 2001
Posts: 769
Likes: 0
From: Granbury TX
How many miles on your car? You might be sucking oil past the valves or reving the engine up at WOT may have just shaken out some carbon. Call me crazy, but I don't think Fuel Pressure would affect the visable effluent from your exhaust.
Rock on.
Rock on.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
the fuel pressure readings looks good, which tells you that your Fuel Pump is OK. But there is no real relationship between the fuel pressure put out by your fuel pump, and what your engine's AFR is. This 'Air to Fuel Ratio' is controlled by the PCM and a multitude of engine sensor inputs. Your fuel pressure indicator tells you that you have pretty constant pressure, which is good, at the top of your injectors. Again this has nothing to do whether you are running Rich or Lean.....and has nothing to do with black snow.....but....watch out for the yellow snow.. 
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Apparently those values were taken with the vacuum line connected; testing should be done with the vacuum line removed from the fuel pressure regulator and blocked.
Anyway, since values would be 2-4psi higher with vacuum off, they look OK.
During warmup the ECM runs the mixture rich, before going into closed loop mode. That would account for brown smoke (or in this case snow) during warm up.
Anyway, since values would be 2-4psi higher with vacuum off, they look OK.
During warmup the ECM runs the mixture rich, before going into closed loop mode. That would account for brown smoke (or in this case snow) during warm up.
