i installed it in place.. put the old one back in it held pressure stayed at 61psi for 10 minute then poof it dropped to twenty now won't hold pressure either.. something seems weird... So can the fuel pump not holding pressure make the vehicle run rich?
--------------------------------------------------------- EDIT----------------------------------------------
where is the component in the fuel pump assembly that needs to be replaced? is it in the pump its self? Sorry this system seems weird to me, money is low and time is precious!! but is it the pulsator or the pump its self that would need to be replaced? I see pump prices from 50 bux to 120 should i only buy oem? Lots of questions and not much for answers... Sorry

thx Terry
--------------------------------------------------------- EDIT ----------------------------------------------
put another new fpr in same results pressure comes up to 64 then bleeds off in seconds... scan tool is reading 14.7 afr always...

warming up the old exhaust analyzer as we speak... still no back pressure in the exhaust even unbolted the muffler and converter still gets smoking hot...

not sure a fuel pump would do anything but its cause i don't understand the system and with a second opinion i'd try it they seem to run about 80 bux... my budget is getting tight lol

 

not sure if this is legal but wanting to keep these seperate...

hooked up the exhaust analyzer hhc was over 4000 co over 5 afr 18/1...

just cause i decided to pull off the egr and it was stuck wide open huge chunks of carbon stuck in it...

now the fuel still kinda bugs me pressure running is 55 rev it and it drops to 50, but its smooth...

would still like to be enlightened as to what all is in the pump that controls fuel pressure and holding the pressure.. I am not doubting I am just curious as to my knowledge it just has a straight return to the tank... but would change it if still needed when there's less gas in it as it is full now...


thanks for all the help guys REALLY appreciate it but would love to learn more as i hope it last long enough for me to learn to like it...

 

The fuel pump, like just about any pump, produces a certain pressure at a certain flow rate. The pump itself should be able to produce at least 60psi of pressure at the maximum flow rate that the engine requires. At lower flow rates, the fuel pressure regulator is what controls the pressure by dumping excess supply back to the tank via the return line.

 

Ok i get that... And should be able to maintain it no matter what the engine demands... What about the bleed down test on the 95 blazer?

I there a second regulator in the return line or in the tank is what i am not getting... Check valve or something... that maintains the pressure you were talking about, It still bleeds off pretty fast, no where near 55psi for 10 minutes... Cycle the key you get 61psi.. Running about 58psi.. Snap the throttle drops to 50psi and returns... I want it to run right and be dependable for my family...

When money permits i'll swap out the fuel and should i put on a different then Dorman regulator(that's what was available) Delphi = OEM?

thx for picking your brain for me

 

The return line is wide open to the tank. The pump has a check valve in it that holds pressure in the system after it shuts down.

The procedure in the Tech Article section should mention testing at the fuel filter to remove the engine side of the fuel system from the equation. Some adapters are required for this, but it is very effective at narrowing down the potential leak sources.

 

ok now i get it... Thank you.. The explanation make devising a tester much simpler too... Is there any chance of damage to the pump if energized too long?

Thx Terry