Three dead fuel pressure regulators means a bigger issue?

Okay! I called Fuel Lab, and they have great customer service. All the regulators are 1:1 rising rate, or at least all the MINI series are. I guess I need the 53501. I'm pulling the trigger on this. It's roughly the same size as the stock unit, so I'm hoping I can find a way to mount it in the stock location. I really like the look of the fuel lab, and the size is great. I also love that it has a port on the front for a pressure gauge… no more bleeding the system and installing a pressure tester! Hopefully this is a permanent fix, and will be a good investment later on when I build the VG33 I hope to put in! Thanks for all the help, guys!

you're going to have trouble mounting that in the same location and getting the lines to fit perfect. the stock reg has lines that curve towards the regulator on an angle. i had to mount my and fabricate some 3/8 brake line with bubble flare fittings to re route my fuel pressure regulator to where the EGR was.

Damn. That's a pretty engine! I'll look at it and see what I can do to make it fit. The hard part right now is figuring out what gauge to use!

I went with a dry gauge. The oil filled gauges change pressure based on temperature. The dry ones stay accurate, but sometimes fail due to vibration… It was inexpensive enough, if it does I will switch.

thanks. years of fuel leaks from not having the proper upper intake to make the change over to my dedicated fuel rails were not kind to the motor. it runs great, but it the valve covers look poo.

I'm not sure I've ever seen your build thread… That just occurred to me.

I just realized the new FPR will change more than the old location… I assume I no longer use the fuel temperature sender and the solenoid? I may find a way to leave the sender attached, just so the ECU doesn't report that as a code. That, or maybe install the appropriate value resistor on that wire. Not that it matters much, I just don't like useless codes. I'm OCD about weird things that shouldn't matter.

pretty sure you've never seen my build thread. i don't have one.

the fuel temp sender only works to open the surge tank pressure to give the fuel pressure regulator pressure when you're trying to start up. you can mount the fuel temp sender two ways. get a T fitting for your gauge and put a plug into the T port, then drill and tap it to the same thread as the Fuel Temp Sensor.

And reroute your vac lines so that everything remains the same, it will still work exactly like stock.

That would explain why I haven't seen it then!

I was under the impression that the '85T didn't have a surge tank… I am also running an '84T ECU.

it doesn't have a surge tank. I'm not sure how the Fuel Pressure Solenoid works on the 85's. I don't have one.

But either way, you could just reroute the vacuum lines with some silicone line so its nice and shiney and black and whatnot rather than dark grey and old lookin' as soon as you take it out of the package.

I already have a ton of silicone line laying around, so I will definitely do that!

I went ahead and bought a z32 fuel filter as well. All new rubber lines, filter, regulator, gauge, etc will be going in soon. Hopefully that will finally be it with the fuel system for now, until I can afford to tear it apart and replace/clean the injectors.

I'm struggling to get the fuel pressure set correctly. I read a NICO forum post for a 240sx, and they suggested using a jumper on the fuel pump relay to activate the pump and keep it running with the engine off, so the fuel pressure could be set more precisely. (Since the pressure will be more consistent without the injectors releasing.) Should the pressure still be set to 37psi? (Since there will be no vacuum).

I ask, because the car still runs poorly. Set to 30psi at idle, it misfires and has no power on boost. If I turn it up to around 35psi at idle, it runs much better, but still somewhat down on power, and misfires. Today I am going to revisit all the settings on my car (TPS, FPR, idle, etc.) and pull the cat to see if that is plugged. I just can't shake the feeling that there is another problem.

Unless your regulator is retarded, or your pump dying, it should have no trouble adjusting to a given pressure with or without injectors… don't overthink this

Fair enough. I think I solved most of the issue today… The new FPR had a vacuum leak. A little teflon tape on the adjustment screw fixed it though, and I re-adjusted everything. Set timing, set fuel pressure, tested the TPS, checked for vacuum leaks, and more. For some reason, the car runs much better with the FPR adjusted with higher pressure than the FSM calls for. It says it should have 30psi at idle, and the car runs much better with about 33-35. Either my pressure gauge is inaccurate, or I'm compensating for something else.

I also tried to adjust idle, but the idle adjustment screw didn't do much. I don't know how much you should have to spin it to make a big difference, but it took about two turns to get maybe 150RPM out of it. Maybe that is a clue to another issue… I did spray brake cleaner around it to see if there was a vacuum leak, but it didn't seem to affect it.

The car runs much better, and is pretty drivable now, but still far from perfect. It doesn't like it when i engine brake (Sometimes it will stall, most of the time it will chug badly and won't accelerate for a few seconds.) To demonstrate this, and to hopefully enlist more help in fixing this, I took a couple videos.

Hopefully this will help!!!

you might just have an injector that isn't spraying as much fuel as it used to due to clogged mini-filter at the injector inlet or just general shittyness with the coil itself, so maybe thats why increased pressure brings joy.