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83' 280zx
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Discussion Starter · #1 ·
I've been having fueling issues, found it was my fuel pressure regulator. Put a aeromotive one on, now I'm idling high till I start adjusting the pressure to factory spec 36 psi. Now it's flooding itself. I've trying adjusting the factory AFM sensor but not much came from that. I'm just stuck of what I should do now. Timing seems to be right, only thing I think I should try is getting new plugs since I think the old ones fouled.
I'll take any suggests, at this point I'm ready to take it to a shop.
 

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I dont know what aeromotive FPR is, but the stock one includes a vacuum line that adjust the FP based on manifold vacuum. the presssure should vary with manifold vacuum. 30inhg is typical at idle where the vacuum is about 17inHg, FP goes up as vacuum decreases (no vacuum should be about 36psi).
I recommend you stick with OE parts if you want to get help or use the FSM for guidance.
 

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83' 280zx
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Discussion Starter · #3 ·
I dont know what aeromotive FPR is, but the stock one includes a vacuum line that adjust the FP based on manifold vacuum. the presssure should vary with manifold vacuum. 30inhg is typical at idle where the vacuum is about 17inHg, FP goes up as vacuum decreases (no vacuum should be about 36psi).
I recommend you stick with OE parts if you want to get help or use the FSM for guidance.
Aeromotive is just a company that made the FPR, but I didn't take the vacuum line off when I was adjusting the psi. Also on the FPR I bought it has a boost reference where it just increases the pressure to a 1:1 ratio so hooking the vacuum line on the boost reference you think that would help?
 

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Aeromotive is just a company that made the FPR, but I didn't take the vacuum line off when I was adjusting the psi. Also on the FPR I bought it has a boost reference where it just increases the pressure to a 1:1 ratio so hooking the vacuum line on the boost reference you think that would help?
The Nissan stock fuel pressure regulator is designed to maintain a Pressure Differential of ~36.3PSI BETWEEN the fuel pressure and the intake manifold pressure. WHEN the intake manifold is in vacuum the FPR removes a like amount of pressure from the fuel rail. IN BOOST it adds the amount of boost pressure to the fuel pressure.

To maintain the expected stock fuel pressure your FPR needs the reference air tube connected AND at ZERO (0) PSI manifold pressure (fuel pump working, engine not running) your adjustable FPR should be set to ~36.3 PSI.

The reference line on the adjustable FPR will do the same thing that the "vacuum hose" on the stock FPR does - maintain the pressure differential between the fuel rail and the intake manifold.
 

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Discussion Starter · #7 ·
The Nissan stock fuel pressure regulator is designed to maintain a Pressure Differential of ~36.3PSI BETWEEN the fuel pressure and the intake manifold pressure. WHEN the intake manifold is in vacuum the FPR removes a like amount of pressure from the fuel rail. IN BOOST it adds the amount of boost pressure to the fuel pressure.

To maintain the expected stock fuel pressure your FPR needs the reference air tube connected AND at ZERO (0) PSI manifold pressure (fuel pump working, engine not running) your adjustable FPR should be set to ~36.3 PSI.

The reference line on the adjustable FPR will do the same thing that the "vacuum hose" on the stock FPR does - maintain the pressure differential between the fuel rail and the intake manifold.
I'll try that when I can get the chance, thanks for the information I couldn't find anywhere else. Especially information on the reference line on my FPR. I'll let you know how this goes when I try this.
 
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