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SC400 Max Fuel Pressure (help please!)

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Old 08-02-14, 03:12 PM   #1
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Default SC400 Max Fuel Pressure (help please!)

I have a sc400 with 1jz single swap. Stock sc400 fuel pump, stock lines, AEM FPR, 440cc injectors (750s and rail waiting to go in ), big 70mm turbo.

I need to know what is the max fuel pressure that a healthy stock sc400 fuel system can put out?

I am having leaning issues starting around 7-8psi. I have already tried adjusting fuel map all the way up at those datum points. I just don't think I am supplying enough fuel. BUT, I have had the car for 4 months now, and haven't had these issues. I am wondering if my fuel pump and/or filter are going bad. Although, previous owner supposedly put brand new pump in shortly before I picked it up.

The MOST I can adjust the FPR up to is 38PSI (with vacuum connected). I seem to think before when I first started tuning it, that I was able to adjust it much more than that.

Please guys, give me some numbers if you know them and thanks.
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Old 08-09-14, 12:43 PM   #2
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anyone know? Thanks
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Old 08-09-14, 03:09 PM   #3
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I don't know the answer, but I'm pretty sure I've seen 38-44 psi listed as the typical range. (Not sure if that's just the 1UZ or also the JZ variants.) That would indicate you're too low if 38 is your max adjustable.
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Old 08-10-14, 07:13 PM   #4
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Thanks bud. I came across a page in the manual that says that with vacuum disconnected, expect 38-44psi. With vacuum connected, expect 28-34psi. So, I guess the pump is putting out what it's supposed to. I will have to see what happens when I put in the larger injectors. Might have to go to a walbro.
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Old 08-10-14, 08:36 PM   #5
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If you can only get 38psi out of your adjustable pressure regulator then you have a leak somewhere or the diaphragm is going bad
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Old 09-16-14, 07:59 PM   #6
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This problem ended up being the fuel pump. Previous owner had a stock SC400 pump installed, which apparently got lazy. I also changed the fuel filter. The old filter had much more restriction while blowing through it than the new one. That however, did little to help the situation. Once I installed an Aeromotive 340 stealth, the leaning issues went away, and I was able to adjust fuel pressure to at least 60 psi (didn't try to go anymore but could've). Thanks guys
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Old 09-16-14, 07:59 PM
 
 
 
 
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