Installed Nismo FPR, Set Pressure Correctly, Runs Worse Than Ever Now ???

[rico05]

So, with the vac line hooked up on my stock FPR (Walbro pump) I was getting ~36psi. I know it is supposed to be 28PSI, so I bought a Nismo FPR, set the pressure to 28psi (36psi vac line unhooked) and now the car starts like crap, bogs anytime throttle is applied, and generally runs like ***. Now, I am running BCPR7ES-11s that I am 99% sure are toast, so that could be the issue, but I wanted to wait until I get my my new intake tube and recirculate my BOV before I changed plugs. Any ideas on WTF is up? I am goig to check it all before I go to work today, so any help would be muy appreciated.

[float_6969]

Don't set it with the car running, it's too hard, and I don't think 28psi is right actually.

Turn the ignition ON.

Remove the Fuel pump relay in the black box by the battery.

Get a short piece of wire with the two ends bared.

If you look at the top of the relay, there is a small diagram. What it is illustrating is the two "sides" of the relay. There is a coil side, and a contact side. The coil side is designated by a little coil of wire. The contactor side looks like a bridge that is lifted up. This is the side you want. On mine it's labeled as contacts 3 & 5. If you flip the relay over, there are 4 connections. In VERY small print, down inside, right next to the terminals, there are numbers. They correspond to the diagram on the top of the relay. There are two terminals close together, and two farther apart. On mine it is the two that are close together that are the contact side.

Place the two ends of the wire into the relay RECEPTACLE in the fuse box. On mine it is the two that are close together.

The fuel pump should kick on and you should see fuel pressure.

Adjust the pump to 36psi.

Remove jumper, reinstall relay, and fuse box cover.

Lower any values that you may have adjusted on the SAFC in the idle range.

You should be good to go.

EDIT: here is a crappy diagram of the relay

2 -0000- 4

3 ------\ ------ 5

[damesta]

Check and make sure the nismo fpr isn't leaking vacuum as well, Ive seen of them do that.

[rico05]

Thanks Ryan, I will go give that a try. And FYI, I don't have a SAFC (wish I did)

EDIT: Thanks Ryan. Runs like a top now.
Modified by rico05 at 10:53 AM 9/8/2006

[dat_twinkie]

i was wondering which type nismo fpr did you get the type a/b? im planning on getting one, but don't know which one to get..

[rico05]

Not aware of "a" or "b". It is the bolt on for SR/RB/VG, part#: 22670-RR710-US. You just have to loop a little extra fuel line to get back to the hard line.

[240 Trainee]

where did you put the gauge? I thought it has to go post - fpr, but the nismo fpr bolts right to the fuel rail. Just curious.

[Fenvy]

float_6969, thanks for the info

[nismoplsr]

T

where did you put the gauge? I thought it has to go post - fpr, but the nismo fpr bolts right to the fuel rail. Just curious.

The fuel runs though tthe system as follows:

Tank--Pump--Feed Line--Fuel rail--FPR--return line--tank.

The FPR just basically punches off the fuel flow out of the fuel rail thus creating a pressure build up PRE-FPR. You need to put a gauge before the fuel rail.

[float_6969]

I've got my gauge "T'd" in after the fuel filter, before the hardline at the back of the manifold that feeds the fuel rail.

[rico05]

You can see the blue Moroso inline T fitting on the fule line before the filter. Then it goes fron a 1/8npt fitting, through -6 line, to the Autometer Pro Comp Ultra Lite gauge. It matches my interior gauges

[240 Trainee]

The fuel runs though tthe system as follows:

Tank--Pump--Feed Line--Fuel rail--FPR--return line--tank.

The FPR just basically punches off the fuel flow out of the fuel rail thus creating a pressure build up PRE-FPR. You need to put a gauge before the fuel rail.

I was thinking something along those lines, that kinda makes sense.

[float_6969]

Rico nailed it. Mine is basically like that, only my gauge is screwed right into the T I used.

[ca18datsun510]

fuel pressure should be somewhere between 38-42. not 28.

[teddy]

fuel pressure should be somewhere between 38-42. not 28.

FSM specifies 36 with vacuum disconnected, 28 with it connected. I would post it straight out of the fsm, but I'm too lazy tonight. Is this not correct?

[float_6969]

36psi FTW...

[biosehnsucht]

The problem with "28 psi with vacuum connected" is what is "vacuum" ? How many in/hg, or whatever units? Simpler to just set it at no vacuum ( = atmospheric) since thats what you're really referencing fuel pressure to anyways. Setting it to "on vacuum" is trying to guess how much difference in vacuum from ambient air pressure there is, and hope you're right. Even if you car was running 100% to begin with, this is a dodgy method.

[float_6969]

Exactly. I promise, as rico can attest to, if you follow the method that I have outlined, you'll get it reset perfectly.

[rico05]

Yeah, the FSM even says to hook it up to a varible vac source. I have no clue wtf that even is, lol (I get the idea, just not what aparatus can do that for me) Ryan's method works spot on.