I have taken a TPI system and swapped it into my car. I am using a 165 ECU. I had everything installed and I had a decent tune with the car and I was driving it when the swap was completed. After about three weeks I came out one day and it would start every time but die after about 10 seconds. I tried to figure out what was the issue. I pushed and injector up in the rail a little and it started again and would run but I had no leaks before I did anything. It almost seemed like I was losing fuel pressure. I replaced the original injectors with the correct 22/lb bosch 3s from southbay and the issue returned. I installed the injectors in the intake first and I have no fuel leaks from the rail. However I still can start my engine and it dies right away still. I pulled a log and looked at it in tuner pro and the engine is very lean 18-20AFR then it dies. It is possible to keep the engine running if I change the injector size from 22/lb to 17-16/lb in the prom but that is not right. I also can keep the engine running if I feather the gas like due to the acceleration enrichment but if I stop the engine dies. In the logs all of my sensors are working air temp, tps, coolant temp, etc. It is running super lean like its not getting enough fuel. Everything in my fuel system is new I am not sure what would be causing this. Is it possible to install the injectors wrong in the rail and lose fuel pressure but not have any leaks? I dont trust my fuel pressure gauge I think I need another one. When I installed the new southbay fuel injectors and a 2nd new fuel pump it is showing 0psi but the engine will still start which I find unlikely.

Chevy 350 Engine
Manual Trans
New Gas Tank
Two New Fuel Pumps (GSS340 Walboro)
New Fuel Filter
Two New Non-Adjustable Fuel Pressure Regulators
New Supply and Return Line to and From Gas Tank
No Visible Fuel Leaks
New Southbay Injectors 280155700 w/corrected voltage offsets in prom
Tried Two Separate 12V sources to run fuel pump and checked voltage at fuel pump.
Running 1/2in Fuel Line or -8an
No Kinks or Bends in Fuel Line

 

What is your IAC doing? What is your idle RPMs at? Sure there are no intake leaks? Any between the plenum and runners? Lean may not be lack of fuel, but could be excess air. Or, a bad 02... but I am assuming you are in Open loop so that would point to issues in the base tuning.

You said it seemed like you were losing pressure and you don't trust your gage. I would get a gage you trust and verify loss of pressure before you toss more parts at your fuel system. You didn't post any of your readings. The easiest to check for is to Key on, let pressure build, and then key off... don't start, and watch how it bleeds off.

 

I checked for vacuum leaks and did not find any. I have replaced the IAC also its my second new one so that should not be the issue. Idle rpm is set to 750rpm. After it comes off the fast idle initially it dies. I figured out that the 90degree fitting on the fuel rail is causing my gauge issues. I have the tpi intake taken apart so I can hook the fuel gauge directly to it. I took the 2nd new fuel pressure regulator off and found that there was an issue when I installed the 2nd new fuel pressure regulator. One of the plastic flaps on the fuel pressure regulator was bent when I installed it. I fixed that. When I prime the pump I get 43ish psi of pressure but it quickly bleeds off. I ordered an inline fuel pressure check valve I will install.

 

I installed the inline check valve in my supply line. I have been playing with my tune. Seems like my engine is not making the power it should be. I have my 22lb injectors set to 20lb. I also adjusted the VE table. I can get 14AFR when idling/cruising around. As soon as I hit the throttle though it just goes dead lean 18-19AFR. I have been adjusting the acceleration enrichment today but the adjustment does not seem to keep it from going lean.

 

I was able to remove my map sensor and I set it on my engine. That allowed me to put the fuel gauge on my fuel rail and run the engine. I am getting high 30s on my fuel pressure with the regulator under vacuum. Without vacuum the fuel pressure is in the low 40s where it should be. Seems like the issue was caused by a poor regulator installation probably was in a hurry.