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Old 07-16-2008, 11:53 AM   #1
blowbyu24
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Default high fuel pressure problem, blew a hole in fuel line

fuel system
ur 1000cc injectors
ur custom fuel rail
dual walbro system
no name fpr non adjustable with just a gauge on it

well i was driving home from work yesterday and i was getting onto the highway and got on it and not even 10 secs later i felt a loss of power and raw fuel smell...so i pulled over and found out the line leaving my aftermarket fuel pressure reg was torn...i was like holy **** i couldn't believe it....so i call my g/f and she went out and got some high pressure line and i put that in started the car and the gauge on the fpr was reading about 84psi...way higher than normal...now i know i know you guys are going to kill me, the only part i went cheap on with the whole build was this no name fpr...and what do you know..i think thats is what is wrong

so anyways i put on another line and just primed it and then turned on the car and after about 10 secs the line started to bubble right before the T heading back in to the fuel lines, it bubbled so quickly that i went and turned off the car and before i could the line split again in the same spot that the first line did....then i was left without the car being able to run...and it turned out to be a very very long night...thats for another time

possible problems i can't think of why all the sudden the fuel pressure would jump so high and then to blow holes in two fuel lines leaving the fpr....i am thinking when i was at wot the fpr failed...i guess they are pretty sensitive..
any other suggestions

i still have my stock fpr....i guess i could throw that on, i don't know if that is made to handle 1000cc injectors with dual walbros system though..

i am kinda at a loss for why the pressure is really high...i checked the fuel system pretty good and all other lines look to be in good shape

Last edited by blowbyu24; 07-16-2008 at 12:01 PM.
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Old 07-16-2008, 12:07 PM   #2
Mechie3
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Sounds like your FPR is stuck in a closed position and not allowing pressure to bleed off. When you hit WOT and the boost increased fuel pressure it might have jammed it beyond the limits of the FPR or just gotten an 0-ring or piston stuck. The flow from dual walbros may outflow the limits of the stock FPR, though I'm not positive.
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Old 07-16-2008, 12:15 PM   #3
blowbyu24
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^^^thanks, thats what i am thinking about the frp being stuck closed or something...for it to not allow fuel through and increase the pressure

b/c i can't think of another reason for fuel pressure to jump that high

and i am not sure about the stock fpr

comments would be great from anyone
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Old 07-16-2008, 12:29 PM   #4
charliew
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You might have some object such as pieces of fuel hose stuck in the line restricting the flow. The fpr return line should not be restricted and allow any pressure except for the size of the line. It should be open all the way to the tank with no restriction.

It sounds like you have mistaken the pressure feed line for the return line.

You have a feed line from the pumps, under pressure, a single line with a tee to the rails, or two lines to the rails, under pressure, and the return line that only the size of the line is the restriction to the tank.

I guess with no vaccum to the fpr such as when you crank the motor the fpr is closed and the spring opens at the set pressure to return the fuel to the tank. You might put a hose on the return fitting into a bucket and see what the pressure goes to with the key on. That would tell you if the return line to the tank is where the restriction is.

Last edited by charliew; 07-16-2008 at 12:44 PM.
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Old 07-16-2008, 01:09 PM   #5
blowbyu24
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Quote:
Originally Posted by charliew View Post
You might have some object such as pieces of fuel hose stuck in the line restricting the flow. The fpr return line should not be restricted and allow any pressure except for the size of the line. It should be open all the way to the tank with no restriction.

It sounds like you have mistaken the pressure feed line for the return line.

You have a feed line from the pumps, under pressure, a single line with a tee to the rails, or two lines to the rails, under pressure, and the return line that only the size of the line is the restriction to the tank.

I guess with no vaccum to the fpr such as when you crank the motor the fpr is closed and the spring opens at the set pressure to return the fuel to the tank. You might put a hose on the return fitting into a bucket and see what the pressure goes to with the key on. That would tell you if the return line to the tank is where the restriction is.
yeah you are right...i confused the return and pressure line...

yeah ill explain to the best i can...theres two lines coming from the fuel system(tank and fuel pumps)...the left line goes into a fuel filter and then runs to the fuel rails(i believe pressure line) and then the other line fuel line goes from the fuel rail to the t and then into the bottom of the fpr and then through the fpr back to the (return line)

the burst is where the fpr line leaving the fpr meets the fuel line at the t...its right before the t..thats where it is wanting to bubble...i pulled the tee off and there was nothing resticting the line going to through the T....

so the fuel must be getting stuck trying to go back into the fpr from the fuel rail return line

so the fuel must be coming from the return line from the fuel rails and then going through the t and getting stuck at the fpr and the weak point is right before the t and that is where it is wanting to burst

does that seem right??
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Old 07-16-2008, 02:23 PM   #6
Homemade WRX
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so you're using regular fuel line for the pressure side of your system?!! or so your description of the system implies.
who's fuel rails/system are you using?!! who did the install?

be glad that using the cheap line and not braided didn't fail when WOT causing a lean condition or worse catching the car on fire
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Old 07-16-2008, 02:51 PM   #7
blowbyu24
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^^^its not the install, it is the crappy fpr that is causing the fail, i believe

yeah i am glad it burst after i got on it...wayy too much pressure for that specific part of the line to handle

i am going to see if my g/f father will bring down his compressor and shoot some air into the fpr and get the blockage out of there
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Old 07-16-2008, 07:11 PM   #8
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I understand the FPR caused the failure but I personally wouldn't use standard rubber fuel line on the pressure side of my fuel rail kit.
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Old 07-16-2008, 08:42 PM   #9
reddevil
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Are you sure you are using fuel injector hose? and not just fuel hose? BIG difference, and it shouldnt have burst the second time so fast. I was running 140 psi in my lines under boost, no problems.
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Old 07-17-2008, 10:46 AM   #10
blowbyu24
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^^^yeah its a high pressure fuel injection hose

***UPDATE***

well i took out the FPR and took it apart and the disk inside the FPR was loose so i tighten it and put it back together and now the fuel pressure is 38psi at idle no longer 84-88psi

well i went and drove it around and the car was jerky and breaking up under excelleration..so i turned around right away and pulled the car into the garage...i think maybe now it is too tight and pressure is too low...what a simple thing to throw off the entire car....i really don't know the dynamics of the inside of a FPR so i didn't know how loose or how tight the disk inside there should be.....to break it down real quick...the left side has a spring with a disk on either side then theres a gasket that separtes the left from the right and the other side has a disk that looks like a silver dollar with four or five holes in it and then the other side of the disk has a nippe with threads on it to screw it into the FPR which leads to the fuel return line i believe....so when putting it back together i didn't know how tight to put it, when i first opened up the FPR the disk was loose you could wabble it from side to side almost, thats how loose it was, there was only a few threads of a the nippple holding it on

anyone with experience taking apart a FPR that looks like this one

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Old 07-17-2008, 11:20 AM   #11
charliew
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Put a compressor on it with a regulator set at the pressure you want the fuel to be. Adjust the spring pressure in the fpr to hold that pressure, the return should bleed off the extra pressure when you add more pressure from the compressor when it is set where you want it.

It really sounds like you were using the wrong fuel line.
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Old 07-17-2008, 03:32 PM   #12
blowbyu24
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i ordered an A1000 FPR

that should fix the whole problem
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Old 07-17-2008, 08:09 PM   #13
Turbo_Mike
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yup, thats a great regulator...
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