LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

how to adjust fuel pressure regulator?

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Old Aug 8, 2005 | 09:00 PM
  #1  
94PurplePearlZ28's Avatar
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how to adjust fuel pressure regulator?

which way do i turn it to lower pressure? previous owner set it to 62+, mpg is bad and i believe i will benifit in my mpg and hp by setting it to stock or a tad lower to lean it out. if it is at 62 how many turns would i turn it to get to 40? im trying to guestimate without a guage right now. i turned it OUT a good full turn and it still smells rich but it revs up even faster then before(thats fast) and has a NASTY rasp when it revs down. sounds completely different. sounds freakin awsome.
Old Aug 8, 2005 | 09:09 PM
  #2  
InsuranceGuy's Avatar
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Re: how to adjust fuel pressure regulator?

Turn it OUT to lower the pressure. To drop from 62 to 40 psi will take
quite a few turns and I don't know any way to determine your pressure
without a gauge.

Emil:93Z,383,Vortech,NOS
Old Aug 8, 2005 | 09:28 PM
  #3  
94PurplePearlZ28's Avatar
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Re: how to adjust fuel pressure regulator?

i am out a total of a lil over 1.5 turns now probably and i just drove it. it seems like it pulls harder already. 4th takes no time now with 3.42's it is really starting to pull like a train. i think this car has been overloaded with gas for a long time.

give me a rough estimate on how many turns it will take. and will it hurt anything if i do go to low with the pressure.
Old Aug 8, 2005 | 10:30 PM
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Re: how to adjust fuel pressure regulator?

I don't know why you would even try to guess. Use a gauge.
Old Aug 8, 2005 | 10:33 PM
  #5  
94PurplePearlZ28's Avatar
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Re: how to adjust fuel pressure regulator?

i dont have a guage right now, i just dont want it runnin 62psi. i will turn it down another 1.5 turns, to put me at 3 turns out. wonder what that would put me at?
Old Aug 9, 2005 | 09:46 AM
  #6  
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Re: how to adjust fuel pressure regulator?

Just curious.... if you don't have a gauge, how do you know it was set at "62+"?

You need to set it correctly, using a pressure gauge. Anything less may screw things up worse than they were before.

At 62psi, the injectors are flowing 20% more fuel than they would at 43.5psi. The PCM can not "cut" that much fuel using the long term fuel corrections. You should have been getting "rich" codes from both O2 sensors and the SES light that goes with it.

Do you know why he set it at 62+psi? Is it possible he tried to make up for undersized injectors, increasing the fuel prsssure AND correctly increasing the injector flow constant in the PCM?
Old Aug 10, 2005 | 12:18 AM
  #7  
94PurplePearlZ28's Avatar
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Re: how to adjust fuel pressure regulator?

my friend(original owner) said he did it, at 62. and he said it SEEMED to run better.

i am getting 30lb injectors saturday. i dont want that much pressure between now and then. i guess i will just find a guage.
Old Aug 10, 2005 | 12:32 AM
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Re: how to adjust fuel pressure regulator?

Go buy a guage.
Is it worth your motor if you go to lean and hurt it?
This is a given in my opinion, you need a fuel pressure guage in your 4th gen tool box.
Old Aug 10, 2005 | 08:15 AM
  #9  
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Re: how to adjust fuel pressure regulator?

Originally Posted by revtime
Go buy a guage.
Is it worth your motor if you go to lean and hurt it?
This is a given in my opinion, you need a fuel pressure guage in your 4th gen tool box.
Or on your dash

http://cjcfo.fbody.com/members/injun.../DCP03459a.jpg
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