I'm guessing I should just replace the pump, but I don't know. When my vehicle warms up, the pressure on the pump drops. It was originally tbi, but I converted it to carb. I have a holley fuel pressure regulator, and when it warms up it's at 6psi, but cold it's at 9 psi. Also I should set the fuel pressure when the engines off correct? thanks in advance IT's an electric pump.

 

Can you measure the pressure ahead of the regulator with the return blocked? It sounds more like a regulator issue than a pump problem.

 

I replaced the gasket inside the pressure regulator, it seems like there's nothing to it, but I don't know. I guess I could clamp the hose for the return, I will do that tomorrow. Either way i'm going to replace the pump when I swap rears. Would a normal tbi fuel pump be more than enough for my application, i'm making maybe 375 horse? I never researched, but I don't see why i'd need a better pump if i'm dropping the pressure. Also I should set the pressure with the vehicle off correct? thank you

 

It's a cheap 3 port holley regulator. I forgot to mention that. I did what you said, and when I squeezed the return line the output line pressure dropped to zero. I don't know if that's normal, let me know. I appreciate it.

 

Anyone?

 

When you squeeze the return line shut then the fuel pressure should spike or at least raise from 6psi. Sounds like it could be the pump, but I would make sure because these are not fun to change. I would make sure the pump is grounded good sometimes this will cause one to work slower. It also wouldn't hurt to install a new fuel filter, and then check pressure before the regulator like vader stated. Hope this helps

 

I know how much fun they are to change, but I haven't run the exhaust to the rear yet like I want, and I was going to swap rears. It's not that bad, I have other issues that are worse. I might just try that for now, I was going to wait till next year to swap rears. thanks

 

I was just looking at the regulator I think I have it hooked up wrong. I went to holley's website, and the regulators they show are different. I think I have an older design, on mine the inlet port is on the bottom, and there is two outlets on either side. I'm probably just going to buy a new one.

 

So, does pressure remain if the return line is blocked?

 

If that is the regulator I am thinking of, it doesn't have a return line. It is a dead head style, in the bottom, then each outlet goes to a float bowl inlet (for a carb that has an inlet for each).

Or plug one outlet with the other going to the carb inlet.

That regulator will work OK with the TBI pump. But not with a positive displacement pump such as used in high pressure systems.

RBob.

 

Yeah, holley makes them with the bottom port a return line now. This regulator has the inlet on the bottom and 2 outlets. Now should I run both outlets to my double pumper? I feel like an idiot, I never read what it said on the regulator, it worked fine for me on my iroc. I just replaced the gasket, and hooked it up the same way, but I put a gauge in line now. It's currently set up with one line as a return, when I squeezed that return line pressure did go up slowly, I didn't want to see how high it would go, but it went up to 7.5-8 psi. thanks, I guess I will replace the pump when I swap rears. I'm going to try and fine tune the idle today, as long as the pressure doesn't do the same thing. I also lost my secondary throttle stop screw, does anyone know if I will be able to order this? I didn't know how involved it was to fine tune a carburetor.

 

Anyone know if this is symptom of a bad fuel pump, or should I just replace the regulator with a newer design? Forget the previous questions.

 

Ok, I replaced the regulator with the proper one. A bypass regulator from holley. I still have the same problem, the pressure drops 3psi when warmed up after a couple of minutes driving. If I squeeze the return pressure will increase 6psi I believe, or almost 6, thanks.
I'm going to replace the pump anyway when I swap rears, but i'd like to know for sure if that's the cause. Thanks guys, peace

 

bump