After 7 years of sitting dormant, my camaro is about to live again. I finally installed my new engine, and when I primed the oil pump last night, fuel came out of my supply line.... It was a large amount of fuel, and I was completely taken by surprise.

The key was off, the regulator vacuum hose was not connected, and I primed the oil pump with a priming tool on my cordless drill (not cranking the engine).

What would have caused fuel to pour out of the supply line?

I shrugged this off last night, but when I started my car tonight and stabilized the idle, my fuel pressure jumped to 100 psi and it went pig rich. I could not get the pressure to drop when I turned down the new Kirban pressure regulator. With the engine off, the fuel pressure bleeds down quickly. When I turn the key on, the pump primes to about 80 psi, and is unaffected by adjusting the regulator.

Is there a coorelation between these two issues?

I should mention:
383, AFR 195's, Stealth Ram, 32 lb. type III injectors, Kirban AFPR, Racetronix fuel pump, MadCat preliminary tune (to get car to run with the new CID, injectors, etc.)

 

The fuel pump relay powers the pump, but there is also a redundant switch that activates the fuel pump when the oil pressure is above 2 PSI.

 

Thank you for the quick reply. I was unaware of that switch, but I did wonder if the was such a thing. It was the only possibility that I could think of.

 

That doesn't affect your regulator issue, though.

 

Right. I most likely have an issue with my new Kirban regulator. I spoke with them this morning and they said my issue could only be a plugged return line or bad regulator. He said I should try the original regulator, and if my pressure returns to normal, I can send the Kirban back for replacement.

The problem is that I no longer have the original Holley AFPR to do the swap. I'm considering purchasing an Accufab rail-mounted AFPR and scrapping the Kirban.

 

I'm going to my shop after dinner tonight to check the return line. I'll disconnect the line and blow some air through it with the gas cap removed. That should pretty much tell me where my issue lies.

 

I can blow compressed air through the return line, but it's pretty restricted. I re-installed the Holley regulator, but the fuel pressure hit 100 psi again. I'm beginning to wonder if we got two hoses switched at the fuel sending unit when we replaced the sender and pump.

Any ideas?

The next time I can get back to my shop I'll disconnect the fuel return line at the intake and at the sender and check for restriction again.

 

I swapped the two hoses that I suspected, and then started my car. My fuel pressure holds at 44 psi now (with the vacuum disconnected) and about 40 with vacuum. It was late so I couldn't leave it running long or rev it up to clean it out. It is still 'burn your eyes' rich, but better than before the hose switch. I have more investigating to do, and I'm sure that it'd be helpful to rev the engine a few times to help clear it out.

Is it possible that I wrecked my new O2 sensor already from running so rich? I had my headers ceramic coated this spring so as they heated and cured the coating, would that affect my O2 sensor? The headers did smoke pretty good at first...