Here lately my fuel pressure has been rising as the engine warms up. I put a new Holly regulator on, but this didn't help. My pressure starts out at 6 psi and creeps up to 9-9/12 psi. I run a Mallory comp pump series 140 part # 4140. Any help is appreciated.
Yes the regulator is adjustable, I set it for 6 psi., I never have had a return line and it worked fine, its just a recent problem
As the engine heats up, so does the electric pump from running all that time. You say this is a recent problem, so I would look to the pump. I've also never run a return line and have run probably 15 electric pumps over the years, even on a daily driver for 5 years, so I don't see that as an issue. I know some people swear by them, but lots of us are deadheading the electric pumps (even the builders of marine engines, they run an inline electric pump straight to the engine with no return line) Try another pump and see what happens. Could also be your regulator creeping up on you. Don
I agree with Don. I don't run a return line. I am wondering though ,if with a pump that will push 7 lbs and is regulated for 4-6 , if that has a tendency to overload the pump and cause it to heat up. I use NAPA pump and the first one only lasted about 3000 miles. (it started leaking after storage then failed to pump) The NAPA old timer and former racer said that they don't last that long for that price,. Around $40. I have anEdelbrock carb and reg. set to 4-1/2. Post what you find out, Bob.
Holley regulators are pretty well know in the racing world to creep on the pressure. They are also super easy to rebuild, usually just the diaphragm goes bad. I would buy a new diaphragm and install. Or buy a better but much more expensive regulator. Aeromotive or Barry Grant are both good.
Faulty reg , debris in the reg. , liquid filled gauge ? try a different non liqid filled gauge..... set pressure with engine running.. dave
Are you running a by p*** regulator? The rising pressure is probably from the pump getting hot and swelling. It swells, which makes it tighter and then it pumps better, and over rides your regulater. The Mallory comp series pump is supposed to run a by p*** regulator.
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