Another 454 Vortec Build Thread - Documenting, Q&A, Help

[Bachert24]

After thinking about this a minute, I don't think you had the lines pinched off totally.
If you had a pressure line pinched off, you would get 0 pressure reading. If you pinch the other off, you should get way more pressure.

Yeah that makes sense I’m going try again

 

[BeXtreme]

Yeah that makes sense I’m going try again

Also, the return line will be the one not running through the filter.

 

[Bachert24]

Also, the return line will be the one not running through the filter.

10-4 that helps a ton! I seen 2 soft lines going into hard lines that were stacked on top of each other and tried both, will look a little more closely this time around. I get very little time to mess with this during the week, and of course the person limiting my time is also the one saying "when will the truck be running?"

 

[Bachert24]

You will just end up chasing your tail and spend tons of money to potentially solve nothing like that. There have been lots of good advise on how to simply troubleshoot your problem and you seem to completely ignore it and instead laser focus on something that everyone is telling you IS NOT the problem.

There is no fuel pressure sensor on your truck. The Fuel TANK pressure sensor is only used for EVAP system testing when the truck is first turned on and is not used in your application... regardless of whether there is a sensor installed in your fuel sending unit. The fuel pump itself is the same for almost all GM trucks/SUV's from ~96-2003.

Put a fuel pressure sensor on the rail and then test the pressure(I know you already did this). Record the pressure key on/ engine off. Turn key off and record how fast the pressure drops(PSI/second). Then do what spareparts said and pinch off the return line. Record the key on/ engine off pressure. Turn key off and record how fast the pressure drops(PSI/second). If your pressure with the return line pinched off is over 60psi and it doesn't bleed off very fast after you pinch the return line closed, your entire problem is the FPR. Full stop.

Ok tested following alldatadiy guide. Pull pressure was only 4 psi low on the rail and also 4 psi low with return line pinched off. With that data alldata still says FPR so I’m doing that this weekend. In both instances pressure dropped about 1 psi every 5 seconds so injectors are not ruled out but I believe FPR is the culprit for the running conditions.