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2G Fuel Pressure Too High

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gob4sho89

15+ Year Contributor
215
0
Dec 31, 2006
Farmington Hill, Michigan
I have a walbro 255lph high pressure fuel pump, new stock fuel filter, -6an lines from the filter to the rail, AEM Fuel rail, -6an line from rail to fuel pressure reg, then stock return line. I cannot get my fuel pressure to adjust below 55psi with the hose connected, and it will not go bellow 62psi with the vaccume line off... It easily adjust up, but it only comes down so far... Any ideas would be appreciated... thanks
 
What fuel pressure regulator do you have? It is not adjustable up or down if it is stock. If it is the B&M one it is only adjustable up. You want to adjust/read it with the line disconnected also. The reason it is happening if you have one of those two regulators is your pump is flowing to much fuel at idle/cruise for the regulator to bypass back into the tank. So since the regulator can't bypass it the pressure builds up in the rail.

You want to get this fixed also. The extra pressure in the rail will cause your car to run rich at idle and cruise. The extra fuel in the cylinder will wash down the cylinder walls and contaminate the rings eventually.
 
Do you have the fpr hooked up backwards? I dont even know if that would do that, but maybe?
 
Look in his profile... He has an aeromotive Fuel Pressure Regulator...

I looked in his profile and saw a fully built car with the occupation of high school student. Not many rich parents will completely build a car for their high school student. So I figured maybe he just puts random parts in his profile. Some people do do that.
 
I looked in his profile and saw a fully built car with the occupation of high school student. Not many rich parents will completely build a car for their high school student. So I figured maybe he just puts random parts in his profile. Some people do do that.

I sure as hell wont. I wouldn't appreciate anything in my car if my parents just gave it all to me. I had to work for everything in my car. But as far as the high fuel pressure. It could be bad, help me out guys on that, my if is fuel pressure wasn't working correctly, it wouldn't allow him to adjust the pressure. Not sure, but thats the first thing to come to mind.

James :laser::talon:
 
1. My parents are not rich, nor did they pay for it
2. I have all of these parts are on my car...
3. They are not random, I did a ton of reasearch before purchasing any parts.
4. I built the whole motor myself, in my parents' garage at our house.
5. My parents gave me a small loan at the end of my build so my mom could park her car in the garage again... I will have paid it off by the end of the month.
6. I have worked my *ss off since the 8th grade saving up for my car.

Back to the topic... My Aeromotive FPR is not letting me adjust to below 55-58psi at idle with the vaccume hose disconnected, but it properly adjust above that to 80psi, im sure it would go higher, but I have no reason to test how high I can set it... Does anyone know how I can Fix this to get back to 43.5psi? Thanks for the responses...
 
Defective reg, or theres a restriction somewheres, it's either kinked, or something is blocking it.. And by somewheres I mean from one end of the car to the other.
 
Back to the topic... My Aeromotive FPR is not letting me adjust to below 55-58psi at idle with the vaccume hose disconnected, but it properly adjust above that to 80psi, im sure it would go higher, but I have no reason to test how high I can set it... Does anyone know how I can Fix this to get back to 43.5psi? Thanks for the responses...
There's nothing more we can do to help, other than repeat ourselves.

The regulator is simple. There's an adjustment screw above the diaphragm that allows you to apply or relieve pressure on the diaphragm. IF it is plumped correctly and there are no kinks or other restrictions within the feed and return lines, and pressure is not relieved when adjusting the screw counter-clockwise, then you have a defective regulator. Return it as "defective" to where you purchased it, and have them swap it out for a replacement.
 
I have a walbro 255lph high pressure fuel pump, new stock fuel filter, -6an lines from the filter to the rail, AEM Fuel rail, -6an line from rail to fuel pressure reg, then stock return line. I cannot get my fuel pressure to adjust below 55psi with the hose connected, and it will not go bellow 62psi with the vaccume line off... It easily adjust up, but it only comes down so far... Any ideas would be appreciated... thanks

Have you tried drilling out the orphice in the tank? This helps lower pressure on 2gs. The hole is so tiny it can't flow enough back and the pressure rises. When i drilled mine out with a 1/8 bit i could drop my pressure to 30psi base.
 
Have you tried drilling out the orphice in the tank? This helps lower pressure on 2gs. The hole is so tiny it can't flow enough back and the pressure rises. When i drilled mine out with a 1/8 bit i could drop my pressure to 30psi base.

The siphon that you drilled out is only on 2g awd's due to the saddle tank, OP is your tsi awd?
 
The siphon that you drilled out is only on 2g awd's due to the saddle tank, OP is your tsi awd?
I currently have the same problem with my walboro 450LHP new model with the pressure relief built it ... Automotive 1000 is now on the car after going through 2x fuel lab 515 series regulators (did not fix my issue)... Could someone please give more details on this siphon mod or other issues I may be encountering ... entire fuel system is upgraded besides stock rail and stock return to tank from fpr. walb 450 with high pressure relief, ID1050x, -6an feed lines , stock rail,stock return line .
 
I currently have the same problem with my walboro 450LHP new model with the pressure relief built it ... Automotive 1000 is now on the car after going through 2x fuel lab 515 series regulators (did not fix my issue)... Could someone please give more details on this siphon mod or other issues I may be encountering ... entire fuel system is upgraded besides stock rail and stock return to tank from fpr. walb 450 with high pressure relief, ID1050x, -6an feed lines , stock rail,stock return line .
Just installed a 450 as well. Stock return and pressure hangs at 60 with the car on and the adjustment screw backed all the way out of the regulator body. I believe this is your (our) answer.

https://www.dsmtuners.com/threads/2g-awd-fuel-siphon-mod.350851/
 
I currently have the same problem with my walboro 450LHP new model with the pressure relief built it ... Automotive 1000 is now on the car after going through 2x fuel lab 515 series regulators (did not fix my issue)... Could someone please give more details on this siphon mod or other issues I may be encountering ... entire fuel system is upgraded besides stock rail and stock return to tank from fpr. walb 450 with high pressure relief, ID1050x, -6an feed lines , stock rail,stock return line .

http://www.dsmtuners.com/threads/high-fp-after-installing-new-wally-255-hp.298712/#post-151533883
 
Yessir it is ... I'm gonna try to get it done within next 2 days ..ill give you some feedback ..... Thanks alot!! I saw the siphon mod and feel more re assured that it's the issue

Sure let me know how it goes. Hopefully that helps.
 
Sure let me know how it goes. Hopefully that helps.
Yessir worked like a charm ... it's a little difficult to see the difference by eye ...just measure the drill bit/verify size is 1/8 ...if the bit fits thru the hole ...your good ...very hard to tell you made a difference after the mod ...but yes pressure restriction has been significantly reduced . Thanks again
 
That's what I wanted to hear. I really don't want to modify this and risk breaking it but I want to run the 450 so I guess I'll go for it. Good to hear it worked out.
you'll have the problem with smaller pumps as well from what people have been posting ... it's a simple mod .. I was super nervous at first but you'll get it easy ... remove the plastic piece from the hanger , drill it , pop it back your done ... I do have extra piece/whole hanger assembly actually if you mess up
 
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