I'm hoping someone can help me out. This seems kinda stupid to me, but I just can't figure it out. I just placed an '87 TPI on my 350, and it was running fine, but now it will run for a while, then just lean out and die. I'm running and MSD fuel pump (out of tank), that is capabile of 500 hp. I checked the fuel pressure and the gauge was reading 62 psi. I pulled the old pressure regulator, and replaced it. When I checked the pressure it was about 58 psi. The car will start and run when it is cold, but after it has ran for a while it will just lean out and die. I'm running a wide band O2 and I have the AFR set to about 14.5:1 when the car is idleing. I pulled my return line after the fuel rail and checked for a blocked line. I've got two thing running through my mind now. 1) I have trash in the fuel rail. 2) My fuel pump is supplying too much fuel for the pressure regulator (stock) to vent back to the tank and this is maintaining the 58 psi which is causing my injectors to heat up (i'm not sure if this is even possible, but the injectors get pretty hot). My fuel injectors are 19#. Also, once the car dies it will not start. I can cycle the key about 4 times and use the priming pulse to get fuel in the cylinders. This will allow the car to start and run for a second or two, then die. I'm totally lost please help. Thanks

 

Was this measured just by cycling the key to turn on the fuel pump, or was it measured with the engine running at idle with the vacuum line connected to the FPR?

 

i thought the 19# injectors were for the 305. I think you need either 22# or 24#.

 

The car would be able to idle fine with 19# injectors. Something else is wrong to have that high of fuel pressure with the stock FPR. The high fuel pressure itself shouldn't be causing the lean out and die issue.

 

The fuel pressure was measured both without vacuum line hooked up to FPR at idle 60psi, with vacuum at idle approx 58 psi and by cycling the key 58-60 PSI. I agree that high Fuel Pressure shouldn't cause the car to lean out and die, I'm wondering if this is contributing to another problem.

19# injectors should be fine, because I'm keeping the duty cycle of the injectors down pretty low. The max duty cycle is approx 75% @ WOT, so in my opinion they should work. Let me know If I'm missing something.

I'm going to remove the fuel rail and blow the lines down to see if I have any debris in the lines.

Keep the help coming

 

I must be the first person to have these problems, or people don't seem very interested in this topic; nonetheless here is todays discoveries.
I pulled the fuel rail out and cleaned the lines. I was fairly surprised to find no debris in the lines anywhere. So, this could only mean 1 thing, the stock FPR will not by pass enough fuel to drop my pressure below 60 PSI. To find out if this was true, I pulled my MSD fuel pump off of the car and hooked it up directly to the fuel rail. I piped the supply and return line into a 5gal gas can and lit off the pump. Sure enough the pressure shot up to 60 PSI. I gutted my old pressure regulator to ensure a 3/8 supply and 5/16 return would provide enough of a vent to drop my pressure below 40 PSI. You would expect about 5 to 10 lbs of pressure with no FPR, but with the MSD fuel pump @ 125 PSI and no FPR the pressure held steady at 28 PSI. So, that being said it is very possible that 60 PSI was overdriving my 19# injectors. This has yet to be determined. I guess I will find out once I get an adjustable FPR installed; however, I may just test the car at Idle with 28 PSI and adjust the AFR to idle nicely to see if I overdrive the injectors. If anyone has any comments let me know. Peace out!!

 

I would just run without the FPR then, just leave it gutted and run with 28psi pressure. FPRs are overrated anyway.