Adjustable Fuel Pressure Regulator Question

**garyc4** · 05-15-17, 08:54 PM

Making good progress bringing my 84 back to life. After rebuilding both TB's, installing a new 85 pump and new sending unit, replacing all rubber sections of fuel and return lines, flushing all lines with carb cleaner, converting to an adjustable pressure regulator, and installing a fuel pressure guage, we fired the car today and it ran nicely.

Now the question: When it first fired, pressure was at 8-9 lbs and tab was just about halfway up the slot in the regulator housing. I began adjusting pressure while engine was running, and it rose slowly until it reached 12 psi and went no further. I checked the tab again, and it was all the way at the top of the slot, with no further adjustment available. This was not what I expected.

Anyone have experience with this, and can offer observations or advice?

Also, the front injector had a nice spray pattern, but the rear had a poor pattern and after a few minutes developed a drip and was obviously restricted. I'l remove the rear injector and clean again. Any adice on home injector cleaning remedies appreciated. Thanks.

**KANE** · 12-03-17, 09:52 PM

Fuel pressure is in part a function of the overall output of the pump itself.

The OEM TBI pumps will crank out between 12 -15 PSI max. If you find you need more because of mods, you will need to go to a higher flowing fuel pump, like the 85 & up TPI cars had. I have about 20psi on my rail with an 85 Vette fuel pump.

Hope that helps other folks too...