@Yarb my fuel line comes from the tank to my filter, from there it goes to the rail/injectors, and then I have the FPR right before the return to the tank. 

My fuel pressure was pretty low so I boosted it up to 40psi and that helped a little. Would I need to go higher on pressure if I'm running an aftermarket fuel rail? 

@Zed Head it's definitely running rich, I can smell it in the garage with the fans on and the doors open. I'll test the water temp circuit but I'll only be able to see the low end given that I don't have coolant in the car. 

Doesn't help that I don't have an exhaust on the car at the moment so it's pretty load and difficult to listen to the motor when it's on. But I will say, the throttle response is terrible and it won't hold idle. When I have the throttle down and steady, it seems to be okay. 

How are you getting your fuel pressure readings and how were you able to boost the pressure?

@Yarb I have an aftermarket FPR that is adjustable. 

There is one connector that I can't find where it goes.  Basically a female connector with a black and white wire. It has 14v running to it when the key is in the "on" position. Anyone know where it goes? Ive searched my diagrams and cant figure it out. 

It would be extremely helpful if you list everything that is not stock on the entire car. To this point the only thing I saw by the pic was an aftermarket fuel rail. I assume your inj. Dropping resistors are still in place.

@Yarb whats not stock is the fuel rail, FPR, headers and i took out the egr system. That's all I know of or that I took off/put on. All else is a stock 76 280z. 

Edited August 4, 2024Aug 4 by dar5052

I tried an adjustable FPR on mine when I went to a solid fuel rail and no EGR, never ran right. I put a '78 stock FPR on mine just like you, right before the return, and it runs fine. It's not as cool looking but it runs good.

@siteunseen interesting... I guess it's worth a shot swapping it out because I'm stumped at this point. Seeing as it started to get better as I increased the fuel pressure leads me to believe it has something to do with that. Just a PITA now since I have the AN fittings/lines. Oh well... 

For grins… you can isolate the return line to a gas can and see how much fuel is returning to check the circuit. It should be quite a bit of fuel that cycles through back to the can. A lot more than you imagine. The majority of the fuel being sent gets returned.

I'd make a plan and do the simple stuff first. 

The '78 has one inlet for fuel but up until then they had 2. If you could plug off one side of your old one instead of buying a new FPR????

2 minutes ago, Zed Head said:

I'd make a plan and do the simple stuff first. 

My apologies for hijacking a post but, Zed Head I finally bought a new laptop! Worlds of difference. Yarb said I was only 10 years behind.