How do you adjust the fuel pressure on a TBI?

 

Without modification you don't.

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'92 Astro, GM crate 350, Holley Pro-Jection Intake, MSD 6AL, 3.42's, 2.5" exhaust, Flowmaster 40 2 chamber, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's, Polished & Bored TBI, Custom EPROM in progress

 

If you really want to heres the tech. article about how to do it
https://www.thirdgen.org/newdesign/tech/tbi-afpr.shtml

 

Better yet, visit my website, I have a pdf file with pictures from Vader. He's not into the html tech articles and so I just through it onto my site.
It's really simple.
http://www.0x58.org/jprevost/

 

First step is getting an in-line gauge and find out what you're running now. Once you find out your pressure is too low and you've checked the system for leaks, restriction to flow, or a bad pump, there are a couple things you can do. The easiest thing to do is buy a JET or turbo city adjustable regulator for 60 some odd dollars. If you feel up to it, you can make your existing one adjustable, but be careful, I busted mine. Randy

 

So if i increase the pressure, will this solve the problem of the lean condition at interstate speeds? It started when i got my headers, i get the lean condition light when i travel at 70mph.

 

You may have a vaccum leak, I believe that is also covered by the same code. Your pressure should be between 10-12psi with stock injectors, you should check it before you put a band-aid over another potential problem. If everything else checks out, then I would agree that increasing the pressure will make it richer at cruising speeds. - Randy

 

ok, now this is probable another dumb question, but when you do this, are you using more fuel? Is it gonna kill the gas mileage?

 

well yeah, if you are running lean then that means you have bot enough fuel, so when you rise the fuel pressure, you increase the ammount of fuel you use, porque tu es tonto? jk

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90 RS 305 tbi, 4 3/4" cowl Hood, Edelbrock TES headers, Flowmaster exhaust, Crane roller cam, comp roller rockers, vortec heads/intake, ported tbi, w/new injectors, MSD probillet Distributer/ coil, 1 inch tbi spacer, air foil, 14x4 k&n flat base air cleaner, Rebuilt 700r4 w/ B&M shift kit, B&M Megashifter, 3.23 posi, 2 12 RF's with mtx amp, top of line alpine cd player,autometer phantom gauges, soon to have 91-92 gfx, z-28 wing, new paintjob, rims, all new suspension, and new inteior

 

Probably not.
The ECM is going to try and maintain a 14.7:1 AFR. If it can't do that then it will set a code 44 (if lean).
Knowing what you BL is would be handy.