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Resolved 2G AFPR 55psi?

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Vdubzr32

Proven Member
397
30
Nov 16, 2012
Lake Hopatcong, New_Jersey
ok so i recent installed FIC 2150. Seal n Orings with the injectors. I have a Walboro 450 installed with dual Orings as well. -6an line from pump to rail.

Now two things i lose pressure as soon as I turn the car off. Never did that before when I had PTE 1200 and Walboro 255.

Also when I prime the system from ECMLink my AFPR read 43 psi. Which is correct. When I turn the pump on from Link can adjust the AFPR with an Allen key.

Now when I start the car the AFPR jumps to 55 psi constant. When the car is running I can not adjust the AFPR no matter which way I turn it won’t go down or up.

Am I looking at a vacuum leak somewhere near the injectors or AFPR???

Also to add to this idle slowly starts to Clime to 2k.
 
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I would start by checking the FPR. An easy check for diaphragm operation is to pull the vacuum line. If fuel comes out, the diaphragm is damaged. In addition, if the engine idle does not change slightly when you remove the vacuum line, the FPR may not be operating properly. Also, it wouldn't hurt to try a different gauge to verify your fuel pressure. For your idle, I would start with performing a boost leak test.
 
I would start by checking the FPR. An easy check for diaphragm operation is to pull the vacuum line. If fuel comes out, the diaphragm is damaged. In addition, if the engine idle does not change slightly when you remove the vacuum line, the FPR may not be operating properly. Also, it wouldn't hurt to try a different gauge to verify your fuel pressure. For your idle, I would start with performing a boost leak test.


Good to go, I’ll try this later tonight and keep you guys posted.

Thank you
 
I've heard of people having issues on 2gs with the 450 not being able to lower fuel pressure as well. Might want to look into that just in case.
 
ok so i recent installed FIC 2150. Seal n Orings with the injectors. I have a Walboro 450 installed with dual Orings as well. -6an line from pump to rail.

Now two things i lose pressure as soon as I turn the car off. Never did that before when I had PTE 1200 and Walboro 255.

Also when I prime the system from ECMLink my AFPR read 43 psi. Which is correct. When I turn the pump on from Link can adjust the AFPR with an Allen key.

Now when I start the car the AFPR jumps to 55 psi constant. When the car is running I can not adjust the AFPR no matter which way I turn it won’t go down or up.

Am I looking at a vacuum leak somewhere near the injectors or AFPR???

Also to add to this idle slowly starts to Clime to 2k.

The fuel pressure likely jumps because the 12 volt system is now resting at ~14 volts due to the alternator spinning. This jump in fuel pump flow is likely now overflowing the factory sized fuel siphon used in the 2G AWD cars. Follow the linked guide below to bring that fuel pressure back in line.

https://www.dsmtuners.com/threads/2g-awd-fuel-siphon-mod.350851/
 
The ECU will cut at 1500 rpms so you have additional fuel and or air getting in if the idle goes up that high.
 
Probably over running the drain, or need to drill out the siphon if you havnt. I had a 450 with -6 return and was just fine.

On my evo I can’t get below 45psi even after drilling the siphon and probably need to upgrade the drain on that. But have just been tuning for the slightly higher pressure
 
I will conduct the drilling of the siphon as well as check for vacuum leaks.

What does the siphon do? Hypothetically speaking what happens if it’s removed?

Just for my knowledge.
 
I will conduct the drilling of the siphon as well as check for vacuum leaks.

What does the siphon do? Hypothetically speaking what happens if it’s removed?

Just for my knowledge.

The factory 2G awd cars have a saddle tanknto clear the rear diff and drive shaft. To bring fuel from the driver to the passenger side, the returned fuel is forced through a small orifice that creates a siphoning action. This causes a restriction with higher flowing pumps. By opening that hole some you can remove the restriction causing the uncontrollable fuel pressure, but the increased flow will maintain the siphoning action. Just step your way up slowly until you have control. You don't want to go too big or else the siphoning will no longer function and you'll be stuck with having access to half of your fuel tank.
 
The factory 2G awd cars have a saddle tanknto clear the rear diff and drive shaft. To bring fuel from the driver to the passenger side, the returned fuel is forced through a small orifice that creates a siphoning action. This causes a restriction with higher flowing pumps. By opening that hole some you can remove the restriction causing the uncontrollable fuel pressure, but the increased flow will maintain the siphoning action. Just step your way up slowly until you have control. You don't want to go too big or else the siphoning will no longer function and you'll be stuck with having access to half of your fuel tank.
The siphon will definately still work, the 450 pumps flow a lot, you just can’t make the tube thinner then it is cause it won’t work if it breaks. I used a 9/64 I believe on the evo, not sure what I used in the dsm but the goal is to make the ID completely the same, get rid of the step down completely. But you want to retain it all together or else then you’ll only have half a useable tank. Youll see when you look at it. Doing it in steps is a waste of time installing and uninstalling.
 
The siphon will definately still work, the 450 pumps flow a lot, you just can’t make the tube thinner then it is cause it won’t work if it breaks. I used a 9/64 I believe on the evo, not sure what I used in the dsm but the goal is to make the ID completely the same, get rid of the step down completely. But you want to retain it all together or else then you’ll only have half a useable tank. Youll see when you look at it. Doing it in steps is a waste of time installing and uninstalling.


The factory 2G awd cars have a saddle tanknto clear the rear diff and drive shaft. To bring fuel from the driver to the passenger side, the returned fuel is forced through a small orifice that creates a siphoning action. This causes a restriction with higher flowing pumps. By opening that hole some you can remove the restriction causing the uncontrollable fuel pressure, but the increased flow will maintain the siphoning action. Just step your way up slowly until you have control. You don't want to go too big or else the siphoning will no longer function and you'll be stuck with having access to half of your fuel tank.


Thanks for the response.
 
Update on the high idle all four injector seals worn so i replaced them with new seals and bam idle back to normal.
 
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Video of idle
 
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