Vortec Fuel Pressure

[Hyperti2]

I searched but couldnt really find anything on what is the normal fuel pressure for a 98 vortec 350. My truck has no power above 1/4 throttle so i measured the fuel pressure and i have about 50psi at idle and no increase with throttle. I checked the pressure at the schrader valve right above the intake. It tested 50 i changed the fuel filter and it tested 50 afterwards. Is this a normal pressure or do i have a problem? Thanks guys.

 

[thunderstruck]

I don't know the numbers off the top of my head, but I'm certain that's low.

 

[SAATR]

That's low, as it should be 55 to 60 psi at idle. Likely the pump or FPR.

 

[glfirefighter144]

56-62 I believe is normal key on engine off, running should be 55 or so I think

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[someotherguy]

Actual numbers can vary a bit depending on source, some say 60-66, others 58-62, for the small block. In my experience, 55 would even be on the ragged edge of low. I'm surprised at 50 that it still even starts, since the small block poppet valve setup is so picky about pressure. Gauge accuracy can be an issue so a few psi here or there can be overlooked. If it's been converted to the MPFI setup already these are capable of operating at lower pressure.

Richard

 

[Hyperti2]

Actual numbers can vary a bit depending on source, some say 60-66, others 58-62, for the small block. In my experience, 55 would even be on the ragged edge of low. I'm surprised at 50 that it still even starts, since the small block poppet valve setup is so picky about pressure. Gauge accuracy can be an issue so a few psi here or there can be overlooked. If it's been converted to the MPFI setup already these are capable of operating at lower pressure.

Richard

I havent changed anything injection wise im going to try it with another tester just in case. Where could i find the fuel pressure regulator as SAATR said?

 

[SAATR]

I havent changed anything injection wise im going to try it with another tester just in case. Where could i find the fuel pressure regulator as SAATR said?

It's on the main body of the injection spider, which is located under the upper plenum.

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[Hyperti2]

It's on the main body of the injection spider, which is located under the upper plenum.

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Thanks Man im reading on how to test the regulator now.

 

[Hyperti2]

So ive done a little bit of reading and correct me if im wrong when your fpr goes bad it seems like it commonly leaks causing hard starts i tested my fuel pressure with a known good tester and it read 50psi again. My truck always starts very quick and it has only given me an issue once. This is leading me to think fuel pump. The only issue i have is low pressure and no power. Runs good until 1/4 throttle idles smooth. So do you guys think pump or fpr?

 

[SAATR]

Pump is likely, but I would much rather take a deadhead pressure reading to verify that than guess.

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