I have a 96z28 that runs for a few minutes and then dies so after changing
the fuel pump, filter and regulator, it's still won't run. Ign key on fuel pressure goes to 43 and the drops to zero in about 30 seconds leaving no fuel in the fuel rail so I'm thinking did I get the fuel lines mixed up? And with there being no leaks in the system where would it be losing pressure?

 

As i've learned, the only place it can leak besides out of a broken fuel line is the check valve in the tank (part of the pump assembly), an injector being stuck open, or a faulty fuel pressure regulator. Check to see if you have fuel in the vacuum line from the regulator, if not then try finding your leaky injector.

 

Is the check valve inside of the fuel pump because I just changed the pump itself, and not the whole assembly. So the check valve could be bad? I'm going to check the injectors for leaks.

 

Courtesy of Shoebox: http://www.shbox.com/1/4th_gen_tech2...essure_testing

 

I checked for any leaking injectors and there were none leaking. The regulator, pump and filter are brand new and there aren't any leaks in the lines. What else am I missing?? Could I have possibly gotten the lines crossed where the fuel return line is hooked to the regulator? I just can't figure this one out. The pressure starts at 43 and drops to zero within a minute and I changed everything to prevent that from happening.

 

I had this same thing happen after a fuel pump replacement, I didn't tighten the hoses on the pump enough and was leaking back in from pressure.

 

The supply line (3/8") and the return line (5/16") are different sizes.

 

The pressure stays at 43 and drops immediately once the pump stops running which makes me think it is going back into the tank. That's the only place it can go because it's not coming out of the injectors. What keeps the fuel from going back into the tank?

 

Like I said the lines from the pump to the sending unit is one (mine just needed a half turn snug), fuel pressure regulator is two, or the check valve in the fuel pump is three.

 

When you say check valve in the pump, do you mean the check valve is located inside the actual motor or is it outside located on the pump assembly?

 

It it built into the pump assembly.

 

So that is a different part than the pump. Is it replaceable without getting a whole new assembly?

 

With things like this i think it is better to spend that little bit more money to ensure the job is done right as fuel is one of the things that will cost you more and more all the time and loosing it while you drive is not a good move at all.

 

Sure thing but do you know if that part is replaceable?

 

When I said pump assembly I meant the actual pump itself. If it is the check valve you would need to replace the pump however the car should still run.