331 with fuel pressure issue

[flip4eva83]

Ok, so I just pulled the original motor. There wasnt anything special about just some bolt ons and a chip. It was all put on before I got it. The car started running real s****y, and I already had the 331 built. So out with the old and in with the new. Everything is hooked back up the right way. So here is my issue.

Fuel pressure with key on is around 5psi, 10psi to 15psi while car is running. I think its causing the detonation or whatever it is that im hearing, obviously the car doesnt run well at all. The fuel pressure regulator is about 5 months old, and I just replaced it yesterday with the same non adjustable. The 331 has 30lb inj. Would 30lb inj cause the fuel pressure to drop that much without and adjustable FPR. Before I switched the engines the FPR was running around 35psi.

My fuel system is all stock with exception of 255lph fuel pump and the 30lb injectors.

I need some help here, let me know if you have any ideas. Like is it necessary to get an AFPR which I had and my wonderful wife threw away when it was still new in it package.

Any questions let me know. Thanks in advance.

 

[87AODGT]

you either have a serious leak somewhere or a pinched feed line to have pressure that low

 

[jrichker]

The stock fuel pump (88 LPH) is too small for your current engine. You need a 155LPH or larger pump to match the engine HP and injectors.

Fuel pump pressure test
Disconnect the larger of the two fuel lines up by the Schrader valve. It is the return line and does not have the Schrader valve on it. Find a piece of rubber fuel hose and clamp it on the return line
coming from the regulator. Stick a bolt in the other end of the hose and clamp it. Make sure that
all your connections are tight and leak proof as possible. Be extremely careful that your
test connections have no leaks. There is a definite fire hazard when you do this test.
When this powers up, you don't want fuel squirting everywhere.
Hook up the fuel pressure test gauge to the Schrader valve pressure test port.

Turn the ignition switch on and watch for leaks. You may want to use a helper inside the car
to cut the switch off quickly if you have a leak. To trick the fuel pump into running, find the ECC test connector and jump the connector in the Upper RH corner to ground.

.
Caution!!! You have blocked the return line for the fuel pump! Pressure will rise very quickly past safe levels with a good pump

If the pressure goes up past 55 PSI, the pump is good and the fuel pressure regulator is bad.
If the fuel pressure does not hit 55PSI or more in a few seconds, the pump is bad or you have electrical problems.

 

[flip4eva83]

The fuel system was running fine before the swap and as previously stated the fuel pump (255lph) and the fpr are brand new. I know things do come defective new, but I highly doubt that the 2 fprs I have, which are doing the samething, are both defective. I'm going to give it a shot, but pinching a fuel line sounds more like the culprit, though I'm not a fuel system expert.

 

[HISSIN50]

It should not run on 5-15 PSI. I would use another gauge to be sure the reading is accurate.

 

[flip4eva83]

yeah thats what I was thinking when it started reading 0psi and was still running the same.