Fuel Pressure Question
Thread Starter
Instructor
Joined: Mar 2003
Posts: 176
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From: Holtsville NY
Fuel Pressure Question
I have an intermittent problem where at mid to high RPM (3500-4700) the engine just seems to stumble or stop accelerating. I checked the fuel pressure it sits at 38-40PSI at idle. However it doesn't increase when I open the throttle. It almost seems to drop a pound or two. I took the vaccuum line off the regulator and the pressure goes up to about 46-47PSI. Do I have a fuel pump problem or is this all normal? Thanks for any help
Burning Brakes
Joined: Dec 2004
Posts: 825
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From: Hanging out back with the dark horses. Wa.
I would think it should drop under throttle...... your pushing the fuel out faster.
I have a full time guage in my dodge cummins and it does that. I'm thinking thats not the problem.
any codes?
fuel filter.
MAFS.
TPS.
On and on..... Jeff
I have a full time guage in my dodge cummins and it does that. I'm thinking thats not the problem.
any codes?
fuel filter.
MAFS.
TPS.
On and on..... Jeff
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
When you remove the vacuum line fuel pressure goes to the maximum value allowed by the regulator, similar to what happens when you go to WOT and there is little or no vacuum at the manifold.
I too noticed the slight drop in fuel pressure after going to WOT and replaced my fuel pump. But, in retrospect, I think the drop is due to a slight increase in manifold vacuum shortly after going to WOT.
I too noticed the slight drop in fuel pressure after going to WOT and replaced my fuel pump. But, in retrospect, I think the drop is due to a slight increase in manifold vacuum shortly after going to WOT.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Originally Posted by Epyon127
I have an intermittent problem where at mid to high RPM (3500-4700) the engine just seems to stumble or stop accelerating. I checked the fuel pressure it sits at 38-40PSI at idle. However it doesn't increase when I open the throttle. It almost seems to drop a pound or two. I took the vaccuum line off the regulator and the pressure goes up to about 46-47PSI. Do I have a fuel pump problem or is this all normal? Thanks for any help
One other thing this is the first sign of OPTI failure( I knew you did not want to hear that)
Last edited by Redeasysport; Apr 8, 2005 at 01:00 AM.
