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Supra OG
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2,392 Posts
Discussion Starter · #1 ·
I recently had a FMIC and AEM installed on my stock twin turbo supra. The fuel pressure at idle is around 42 psi. The FPR is stock and I can't think of any reason why the pressure at idle should change from low-to mid 30 psi to 42 psi. The stock FPR is not adjustable and no changes were made to the stock fuel system. Any ideas?
 

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Boost Junkie
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12,740 Posts
Check the vacuum line?

Steve K.
 

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Supra OG
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2,392 Posts
Discussion Starter · #3 ·
Well, the fuel pressure is rising as the boost goes from vacuum to positive boost. But, it's something to recheck. Thanks.
 

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Supra OG
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2,392 Posts
Discussion Starter · #5 ·
I think it does. But why would that cause the pressure to rise. My dad has an AEM single turbo with a mostly stock fuel system except for a fuel rail/bigger injectors and a kenne bell boost-a-pump. That setup has the stock fuel lines forward and back and the boost a pump is run with 12V or more all the time. I can see a possible rise in pressure if the stock return line is overwhelmed, but it seems to be no problem for my dad's setup.
 

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Supra OG
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2,392 Posts
Discussion Starter · #6 ·
Still looking for a response. I don't see how running at 12V should cause the fuel pressure to rise. At 0 psi boost I'm seeing close to 50 psi of fuel pressure. The stock fuel return should be adequate in my opinion even if the fuel pumps are always running at 12V to hold the fuel pressure to the static rating of 43 psi at 0 psi of boost.
 

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Boost Junkie
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12,740 Posts
The 12v is not causing the fuel pressure to rise. The only thing that could cause it to rise would be to add more resistance to the return line-either by damaging the regulator or kinking the return line. I would try a different regulator.

Steve K.
 

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Supra OG
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2,392 Posts
Discussion Starter · #8 ·
Steve, I agree. I asked my mechanic to check the fuel lines over very carefully.
 

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Banned
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1,081 Posts
I also noticed something wierd with my Fuel Gauge after I installed the AEM. It's as if the Fuel pump is creating a larger vacuum and the needle on the fuel guage drops down real quick when you turn the motor on. Once you turn it off, the needle goes up atleast one tick mark. Another thing I noticed is that when I pull into the gas station and unscrew the gas cap, a huge hissing comes out like it's decompression. I never had that a long/huge compression with the stock ECU.

My car has stock twins, fuel pump, injectors, manifold, pretty everything. I'm even using stock sensors with the AEM.

BTW, you should post your question in the Tuning section on www.aempower.com forum.
 
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