I just got my rebuilt 305 TPI engine running last night, but need to set the fuel pressure on my new adjustable fuel pressure regulator. The engine is basically stock with a LT1 cam and shorty headers. What should I set the fuel pressure at? I am going to install a pressure gage off the Schrader Valve tonight.

 

I would go with 5psi over stock. Thats about 50psi. You really need to watch fuel trims to know if your setting is right. If the setting is okay, long term fuel trim(Block Learn) should stay neutral at 128.

 

Ok, I don't know what a fuel trims is, and how do I check for them?

Joe

 

http://www.srtforums.com/forums/f87/explanation-fuel-trims-here-229511/

Well I should have done some research before I left the above message. Above is a good explanation of Fuel Trims.

Thanks,

 

Good job doing your homework.

 

All you have to do to install your AFPR is, first find out what the stock setting is on your car via fuel pressure gauge. Then install your new regulator. Then disconnect regulator vacum hose and plug it. Hook up your gauge and start the car. Then you would adjust it at idle. As another member stated 50 psi is about the max you wanna go. I suggest just going up a couple of pounds from what your stock setting was at first. A pound makes a big difference also.

 

Don't be concerned with fuel trims as your adjusting initial fuel pressure. You will not get an accurate read at idle with no vacuum to regulator. Set base pressure, I actually do this with the FP relay jumpered to run with the engine stopped. Then check running pressure with and without vacuum to regulator to verify proper operation. Now, drive vehicle and monitor Block Learn(Long Term Fuel Trim) while you drive for 10-15 minutes at various speeds and loads. If Block Learn is 128, you are good to go. If Block Learn is higher, raise pressure 1psi, drive and recheck. If BL is lower, reduce fuel pressure 1psi, drive and recheck. Repeat this until Block Learn shows 128 after 15 minutes of driving at all load and speed ranges.