Fuel pressure regulation 95 tbi

So I have a 95 silverado..I stored it many years and since bringing it out it naturally needed a new fuel pump .I put in a new tank with preinstalled fuel pump...Since then the vehicle has had an issue of running rich...after firing the parts cannon [ new coolant sensor,injectors,map,distributor and module fuel filter]I started thinking about the fact that almost all replacement fuel pumps have too high pressure for what there advertised to fit...I put snap on fuel pressure guage online and sure enough the pump is putting out around 30 psi..according to chevy the correct pressure is 15 psi...even though this may not be my issue..I think I should try this.the factory regulator in the tbi may not be able to return this much excess to the tank.so two ways to fix.....1] fuel pressure regulator....or 2] drop tank and put in pump with 15 psi....here is question does anyone know of a fuel pressure regulator that will drop into 15 psi? Most of the regulators seem to only go down to 30psi from higher...the round carburetor style ones with no return outlet only go up to 5 psi..second question does an y one know where to get an in tank fuel pump that puts out 15psi? Chevy discontinued them and they are offering those cheap fuel line mounted thumpers..that usually burn out after a month...thanks for any help!@

vicegripsilverado said:

I put snap on fuel pressure guage online and sure enough the pump is putting out around 30 psi..according to chevy the correct pressure is 15 psi...even though this may not be my issue..I think I should try this.the factory regulator in the tbi may not be able to return this much excess to the tank.

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Yes, 30PSi is too much for a stock TBI engine which, will definitely cause over-fueling and a rich condition. Normally the stock regulator can return enough fuel to maintain that pressure. I have a pump from a 96 Vortec rated 155 L/Hr @ 65PSI and have no problem maintaining desired pressures. You shouldn't need any auxiliary pressure regulators unless your fuel pump is way oversized but, a replacement tank with a pump shouldn't, especially if it's for an 88 - 95 truck!

A couple things to check;
1.) Is your return line restricted in any way - kinked or pinched, a piece of junk stuck in it?
2.) Are the spring and diaphragm in good working condition? After sitting so many years, a rebuild is a good idea. They have kits with the diaphragm included, you just need to by a spring (available online). An Adjustable Fuel Pressure Regulator (in the Throttle Body) is nice but, not necessary.

vicegripsilverado said:

I put snap on fuel pressure guage online and sure enough the pump is putting out around 30 psi..according to chevy the correct pressure is 15 psi

Click to expand...

7.4L are around 30psi...Assuming you're concerned here because you don't have the 7.4?
"When the fuel pump is running, fuel is delivered to the injector(s) and then to the regulator where the system pressure is
controlled to about 62 to 90 kPa (9 to 13 psi) on 4.3L, 5.0L and 5.7L applications.
On 7.4L applications the pump will deliver system pressure that is controlled to about 179-220 kPa (26 to 32 psi). Excess fuel is
then returned to the fuel tank"

Yep, sure sounds like a pump meant for the 7.4 instead of the smaller engines. I'd swap the pump for the correct one.

It's kinda wild that if you look up a tank and pump assembly for a '95, choosing 5.7 or 7.4 doesn't get you different part #'s, although it should. Looks like they're happy just giving you a one-size-fits-"some" solution.

If you look up the pump by itself, the 5.7 shows Delphi FE0115 which is 29psi max but intended for a system pressure of 12psi. The 7.4 shows Delphi FE0112 which is 40psi max, intended for a system pressure of 30psi.

Richard

Yeah, I forgot about them.

someotherguy said:

Yep, sure sounds like a pump meant for the 7.4 instead of the smaller engines. I'd swap the pump for the correct one.

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IDK - a properly working regulator should maintain 15 PSI no problem...

I'm running the Delphi FE0114 and it's holding 13psi in my 93 k1500........says 32 average flow rate...system pressure 62..


hmm..just noticed it says average current draw is 8A.... I think I measured 4A on my tbi truck...Guess Vortec is more demanding and requires it to work harder....

Think about it, when the engine is idling, or even stopped, the regulator needs to maintain pressure set point.

Some of the 350s also have the 30 psi fuel system. They usually have a governed TBI on them though. The pump only pumps fuel, the regulator controls pressure.

PlayingWithTBI said:

Yes, 30PSi is too much for a stock TBI engine which, will definitely cause over-fueling and a rich condition. Normally the stock regulator can return enough fuel to maintain that pressure. I have a pump from a 96 Vortec rated 155 L/Hr @ 65PSI and have no problem maintaining desired pressures. You shouldn't need any auxiliary pressure regulators unless your fuel pump is way oversized but, a replacement tank with a pump shouldn't, especially if it's for an 88 - 95 truck!

A couple things to check;
1.) Is your return line restricted in any way - kinked or pinched, a piece of junk stuck in it?
2.) Are the spring and diaphragm in good working condition? After sitting so many years, a rebuild is a good idea. They have kits with the diaphragm included, you just need to by a spring (available online). An Adjustable Fuel Pressure Regulator (in the Throttle Body) is nice but, not necessary.

Click to expand...

Yeah I looked at the regulator when I changed the injectors..spring looked OK changed diaphragm..thought about putting in an adjustable kit they make but the location underneath tbi sucks you need a boy hand to turn the adjuster screw..I want to stop the excess before it gets to the factory regulator on the theory that it was never designed to regulate double the oem pressure...problem is what regulator would do the drop..i bought this regulator but people report it won't drop pressure to 15 in reviews...don't know if i should even bother test it

someotherguy said:

Yep, sure sounds like a pump meant for the 7.4 instead of the smaller engines. I'd swap the pump for the correct one.

It's kinda wild that if you look up a tank and pump assembly for a '95, choosing 5.7 or 7.4 doesn't get you different part #'s, although it should. Looks like they're happy just giving you a one-size-fits-"some" solution.

If you look up the pump by itself, the 5.7 shows Delphi FE0115 which is 29psi max but intended for a system pressure of 12psi. The 7.4 shows Delphi FE0112 which is 40psi max, intended for a system pressure of 30psi.

Richard

Click to expand...

I Looked up the pump on chevrolet website for 95 305 it's discontinued..they show a fuel line external pump...like you see on ebay for 29$ [the delco one is 167]