fuel psi
Thread Starter
Launching!
Joined: Feb 2005
Posts: 229
Likes: 0
From: Camp Lejeune, NC
fuel psi just checked my fuel pressure, it's been breaking up when you give it any throttle and has an intermittent miss at idle, it's running 35 psi at idle and drops to 20 psi when you give it throttle, that seems low what should it be at?
Joined: May 2004
Posts: 1,593
Likes: 267
From: Halfway back on the Highway to Hell...again!
Whoa!!! it should be at 41.5 - 43 at idle and only drop for a split second it throttle is given. and that is usually only down to 38 or so then back up to the running pressure. If you do not have an APR (adjustable pressure regulator) then I would get one and change out your pump ASAP. But is sounds like the pump has had it.
TECH Enthusiast
Joined: Nov 2004
Posts: 660
Likes: 0
Originally Posted by SAPPER
Whoa!!! it should be at 41.5 - 43 at idle and only drop for a split second it throttle is given. and that is usually only down to 38 or so then back up to the running pressure. If you do not have an APR (adjustable pressure regulator) then I would get one and change out your pump ASAP. But is sounds like the pump has had it.
not quite.
it should be +/- 2 psi from 43.5 psi at KOEO (Key On Engine Off). that means no vacuum which is the same as WOT or pulling the vacuum line off the regulator. at idle there IS vacuum and it should drop 3-8 psi from the no vacuum psi reading. 35 is fine for idle, but idle should be the lowest fuel psi that you should see. as you open the throttle there is less vacuum and the fuel pressure will go up towards the no vacuum psi.
so, sapper was wrong, but if your fuel pressure is dropping to 20 psi when you're driving then that's not good. does it stay at 20 psi??
Pull the vaccum tube off the FPR and see if it smells like fresh gasoline, or if it
drips gasoline. This would indicate that your diaphram in your FPR has ruptured,
and needs to be replaced.
If this is not the case, you should look to your fuel filter for obstruction, or
fuel pump failure.
drips gasoline. This would indicate that your diaphram in your FPR has ruptured,
and needs to be replaced.
If this is not the case, you should look to your fuel filter for obstruction, or
fuel pump failure.
