Fuel Pressure to high? Running rich.

[85gbody]

Goodmorning Gbodyforum,
Almost a year ago i purchased a holley mechanical fuel pump model 12-834 to go with my 670 street avenger holley carb that was new as well. I also added a fuel rail with a fuel pressure gauge to go with carb. After my engine build was complete, at start up, my fuel pressure gauge read 5.5- 7 psi which i thought was good since the fuel pump box said the max psi was 7.5, it was good for all that time until about 3 months back when i checked again and the gauge read 7.5- 9psi. Today i checked again and the gauge read 9.5- 11 psi. :evil: I know its running rich and at higher fuel pressure than before cus i can smell the gas when i come to a red light. Sorry for the long story but what can cause this to happen? Would it be the fuel pump or my carb going bad? Or a carb tune? Would that be the cause of the fuel pressure going up? All help or pointers is appreciated. Thanks fellas.

 

[79cutlasssalon442]

Almost sounds like something in the carburetor is plugging up a bit and building up pressure in the fuel rail. Really not too sure though. I'd pull everything apart and check it all over.

 

[tetomas]

First thing to check is the gauge, it could be going bad. Mechanical pumps rarely make MORE pressure when they are going bad, so if the gauge proves out then I would look at the carb. Does the pump have a return line on it? If so the return could be plugging up and causing the higher pressure. At 11 psi you have to be on the upper end of what even a Holley needle and seat can stand for any period of time.

 

[bygddy]

If its a liquid filled guage, pull the little rubber stopper on the back and let the fluid drain out, reinstall the stopper. Generally as they heat up the fluid expandes and will give you a high or fluctuating reading.
Then once you have established accurate pressure check your float level. 9 times out of 10 when I looking at someones "rich condition" the floats are way to high. The rest of the time its to little initial timing and over exposed transfer slots.

 

[85gbody]

I believe theres no return line in the fuel pump. I will check the gauge and see what happens from there. But like bygddy said im having more a guess that itll have something to do with the floats because even if the gauage were bad i dont think it would be putting off a strong "rich" odor. I will try all things asap. Hope it works out. Thanks guys.