I need help bad.... 612whp d16z6

It ran fine until it sat a while, now it is dropping the fuel pressure to 20psi if it seems any load on the engine and leaning out.

I have ran new fuel lines, new pump, checked aem fuel rail, checked fuel cell outlet, I do not know what else to do. Any suggestions would be awesome. Thanks!

 

What fuel pressure regulator?

 

FueLab

 

Sorry if it sounds stupid but, you try adjusting it? What was the result? Is this 20psi reading with or without the vac line attached? Try both?

 

I really appreciate you replying

I took the set screw out and put it back in, and adjusted back to 50psi

With vac hose removed, pressure changes about 10psi

I added 10psi to fpr and turned fuel on, pressure went to 60

I have not tried to drive it with vac disconnected

 

You'll have to plug the line, of course, before you tried without it attached. Now that the pressure is back up, try with it hooked up as usual first.

 

I just tried with vac line unhooked, same problem

 

Sounds like fuel filter is restricted, would not surprise me if the car sat for a while. I would also recommend getting the injectors flow tested

 

I removed fuel filter, everything in car only has probably 20 miles on it, but then sat for a winter.

I just had injectors flow tested, and replaced all fuel lines, and new inline 255 pump (I am leaving the 044 off until I get problem solved)

The only thing not changed in past week is fpr. But it seems I am losing pressure before the regulator, unless for some reason the regulator is lowering pressure just when I put engine under load, which wouldn't make sense because I unplugged vac hose.

 

Pinch off the return Line and see what happens to the pressure , as long as the pump is good it should shoot up..... I would not leave like this long, only a quick test

 

Also, did you use the stock fuel pump sock? These are poorly made aftermarket. The ones that come with whatever pump is usually really squishy and has the tendency to collapse under demand.

 

OP, what kind of fuel are you using ? As Txdragon stated above, an aftermarket sock is typically a cheap/crappy design that doesn't have a frame inside the filter material to keep it from sucking flat (like a stock fuel sock does) and restricting flow/volume when a performance fuel pump is used.

I do know of one replacement fuel sock that is just like the original factory one, but they are discontinued, so you have to find a shop who still has some on the shelf.

 

I am using e85 pump and I have 255 inline feeding 044 inline. I just replaced fpr today.

Here is a vid of fuel pressure during a pull, it just leans out.

Skip to 2:45

 

What kind of hose do you have connecting the pump to the pump hanger inside the tank?

 

Seems to be just under load/demand. You have another fuel pressure regulator to try? We usually don't have extras but, worth a try. Lol! I would guess something internally, probably the spring. Or still possibly the pump sock collapsing under demand.
Edit: I see now you said you replaced the FPR. How bout that fuel sock?

 

Based on that video above... you have a restriction problem, NOT a FPR problem. E85 is hard on parts... check fuel socks, any flexible fuel hoses, and if all of that checks out perfect... replace BOTH fuel pumps.