Welcome to the Corvette Forums at the Corvette Action Center!

LT4 LT4 Fuel pressure regulator

1996 LT4 Topic

Louis Bartay

I have installed a adjustable fuel pressure regulatoe from Breathless Performance and I was trying different P.S.I. settings. Any help would be of great help for best performance.
Louis Bartay 1996 Lt4 coupe
Louis, you really also need to pick up a fuel pressure gauge. I can't remember the stock settings, but I believe you want to set it between 47psi & 49psi......

Fuel Pressure

Hi Jay,
I have the fuel pressure gauge and the instructions with the new regulator said to try different settings for the best performance. I have reprogrammed the computer, a 160 degree thermostat, air foil in the throttle body and a K&N open air filter frame and moved the Maf sensor from the bellows to the air cleaner box with a K&N air filter, so the engine is stock except for what I have replaced.
Regards, Louis
Louis, sounds like you've got a great start:) You're exactly right......I've read before that you should experiment with the car a bit as far as setting the fuel pressure. Every motor will respond a little different depending on what modifications you already have. Best of Luck!

Factory specs VS Performance

Hi there,
The factory specs are between 41 and 47 psi.
You really cannot anticipate which of the setting will be correct, because remember that as engine vacuum changes, the fuel pressure on a stock system does also, to compensate, using the vacuum line coming off the intake.
If you tune higher than 47, you may get a check engine light for a rich condition.
While for cammed and head installed vehicles, 47-49, as JT has noted, will be almost ideal, because the engine can use the extra fuel pressure, to increase the power.
However, with the mods listed, you may set to 47, however, I do not recommend going higher, as your cars engine will not use the extra pressure.
Best to you, c4c5
Thanks to Jay and C4C5 Specialist,

I have the fuel pressure set at 49 P.S.I. and the car runs great, and so far no engine light has come on. If the check engine light does come on will it go off if I lower the fuel pressure back to 46 or so? And will I smell a rich fuel condition like I did when the stock fuel pressure regulator started to leak?

Best Regards, Louis
I don't think you'll have any problems Louis. You're running the right amount of pressure and the car should run good :)

Factory Specs vs Performance

C4C5 Specialist

Thanks for the information on setting the fuel pressure regulator, as the check engine light came on this morning (it is 39 degrees today cold) and it was 90 degrees hot out side when I installed the Breathless adjustable regulator to 50 p.s.i with the vacumm line off and the car ran GREAT. But today it is cold and the service engine soon light came on. So I reset the regulator to 45 p.s.i. with the vacumm lnie off and started the engine and the light is OFF and the car still runs GREAT. I guess you were right about the settings. Why did the light come on when the tempture dropped 50 degrees??
Thanks Again,
Louis Bartay
HI there,
Honestly, I dont think that the regulator caused the concern. I feel that JT was correct. Personally, I would check the codes, as I dont believe that your regulator was the issue.
Please scan the system, and let us know the codes.
Besttoyou, c4c5:hb
fuel pressure


I do not have a scanner to check the codes. I have the Hyper Tech reprogrammer, do I need to reprogram back to the stock settings before I have Mr. GoodWrench check the car? The Chevy dealer charges $79.00 a hour so I need to know if the stock setting is necessary.
Hi there,
I thought you knew you could scan the system from the DIC, using the LCD display on your dash.
All you have to do, is to use a jumper wire, and connect pin 4, and pin 12, at the data link connector, as they are right on top of each other. Then, turn the ignition on, do NOT start the vehicle. Have a pen handy, and watch the display.
You can see the speedo numbers will be actual trouble codes, which will be followed by a H or a C to indicate a history, or current code.
The number directly underneath will be the module number, as the one you are concerned with is 4.1 , ok??
Module #1 is the central control module, #4 is the PCM, #7 is real time damping, if equipped, and #9 is your ABS/TCS. A will be your air bags.
If, at any time, you see "ERR", this means that you have a communications failure. Please keep this in mind.
Let us know how you do, c4c5:hb
fuel pressure

I Jumped The #4 and #12 pins and got C12,9. A 1.0 as the service engine soon light just came on AGAIN. Also last week I added Beriman Chem 12 to the gas tank and the first time the check light came on I topped off the gas tank (5 gallons or so) thinking I used too much Chem 12. I have driven about another five gallons of gas out. What do these codes mean. Help,

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors


MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Top Bottom