Gain extra benefits by becoming a Supporting Member Click here find out how!

Classic Performance Products Nu-Relics Power Windows
American Auto Wire Hellwig Products IncPerformance Rod & Custom
Danchuk Catalog



Username Post: How do I get better fuel pressure        (Topic#365479)
2000 4x4 GMC 
"6th Year" Gold Supporting Member
Posts: 81
2000 4x4 GMC
Loc: MS
Reg: 03-02-15
06-09-21 11:48 PM - Post#2821425    

For the last 8 to10 years my 2000 gmc k2500 w/454 & 5 speed manual trans has never had good fuel pressure. By that I mean 58 to 62 lbs of pressure when running. When the pump comes on it will jump to 58 lbs pressure then fall to 52 lbs. and hold for 30 minutes. With the engine idling at 750 to 800 rpm the pressure is constant at 49 lbs. quickly pressing the gas pedal it jumps for a moment to 59 lbs then falls back to between 49 & 52 lbs. varies every time it’s done. I’ve had 2 different fuel pumps, 2 different fuel pressure regulators.
Changed fuel filter. Still get same pressures but Now pressure will not hold after key is off. No leaks I can see. Lines are not pinched or plugged/restricted. Can I buy a different brand fuel pump assembly? Delphi,ac delco, standard motor. Which pump & pressure regular is the better to get and keep good fuel pressure?



 
someotherguy 
Senior Moderator
Posts: 29435
someotherguy
Loc: Texas
Reg: 08-01-03
06-10-21 08:14 AM - Post#2821441    
    In response to 2000 4x4 GMC

Is the truck running OK?

Do you still have the original injectors?

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
redvett01 
Senior Member
Posts: 1245
redvett01
Loc: Wickenburg, AZ
Reg: 10-23-03
06-10-21 08:59 AM - Post#2821442    
    In response to 2000 4x4 GMC

If you are losing fuel pressure when engine is shut off you have a fuel injector leaking. Fuel pressure being low is another issue it should be 60-66 psi so look at the regulator its possibly leaking, check the vacuum hose for gas in it.

K1500 04 Silverado EXT


 
2000 4x4 GMC 
"6th Year" Gold Supporting Member
Posts: 81
2000 4x4 GMC
Loc: MS
Reg: 03-02-15
06-10-21 08:36 PM - Post#2821464    
    In response to someotherguy

Yes the truck runs. Bucks a little at low rpm. At steady throttle on the interstate it will act like I cut the key off & back on for second. Just doesn’t have the power it should have. Before I had the intake problem it ran fair. No missing, just lacking power. It showed up regularly when I pull the gooseneck & tractor. Struggling to pull them and didn’t have the get up and go like it use to have when not pulling a heavy load.
Yes I have a different set of injectors now. Just a little larger than stock, but said they were good fo stock replacement.
Even before I changed injectors I had the same fuel pressure trouble.



 
2000 4x4 GMC 
"6th Year" Gold Supporting Member
Posts: 81
2000 4x4 GMC
Loc: MS
Reg: 03-02-15
06-10-21 08:44 PM - Post#2821465    
    In response to redvett01

That’s odd. Right before I changed the fuel filter it was holding around 51 to 52 lbs pressure for 35 minutes. Didn’t drive anywhere, just changed filter to see if I could improve pressure. Used a mirror to watch pressure regulator with pump running & after. No leaks visible on regulator, line connections, or coming out of vacuum line. I can’t get to the regulator unless I take off the upper intake or pull the distributor.



 
454cid 
Valued Contributor
Posts: 3209

Age: 48
Loc: West Michigan
Reg: 02-18-12
06-22-21 02:44 PM - Post#2821960    
    In response to redvett01

  • redvett01 Said:
If you are losing fuel pressure when engine is shut off you have a fuel injector leaking. Fuel pressure being low is another issue it should be 60-66 psi so look at the regulator its possibly leaking, check the vacuum hose for gas in it.



That sounds more like small block pressure.


99 K3500 RCLB


 
454cid 
Valued Contributor
Posts: 3209

Age: 48
Loc: West Michigan
Reg: 02-18-12
06-22-21 02:48 PM - Post#2821961    
    In response to 2000 4x4 GMC

  • 2000 4x4 GMC Said:
Can I buy a different brand fuel pump assembly? Delphi,ac delco, standard motor. Which pump & pressure regular is the better to get and keep good fuel pressure?



I've been pretty pleased with my Denso pump.

Do you have the flat four or square four plug at the pump? GM redesigned the plug and many pumps provide a new connector to splice into the truck's wiring harness. I wonder if your pump trouble is electrical. My ground was questionable when I changed the pump last.


99 K3500 RCLB


 
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

190 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.363 seconds.   Total Queries: 16   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 10:14 AM
Top