Extremely High Fuel Pressure
Extremely High Fuel Pressure I just finished building my AI 355 and I started it up for the first time yesterday. The only problem is I have just shy of 80psi of fuel pressure with a manual gauge hooked to the valve near the reg. I shut if off a few seconds after noticing this, didn't want to wash the rings. I have an adjustable so I tried adjusting it and nothing. I put the stock regulator on it and still the same. Everything is the same as when I had my 383. Any ideas? I'm running a Walbro 255.
Okay, I tried a different gauge to rule that out. I pulled the return line off the fuel rail and cycled the pump and nothing came out of the return on the fuel rail. I figure I have a blockage in the fuel rail but, I don't. I also blew air into the fuel feed line and fuel came out of the return line so no blockage in the lines. I need some help with this. What to trouble shoot next?
Last edited by SpeedDensityZ; Aug 7, 2010 at 11:05 AM.
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Joined: Apr 2007
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From: Kempner, TX
I don't even know if it's even possible to do, but any chance the fuel lines got inadverently swapped?
If not, I suspect it's got to be in the return, preventing all that extra fuel from being returned to the tank. Not being able to do so and the pressure just builds and builds.
Jake
If not, I suspect it's got to be in the return, preventing all that extra fuel from being returned to the tank. Not being able to do so and the pressure just builds and builds.
Jake
It's definitley a return issue. I just swapped the regulator with my buddies and we disconnected the the return hose off the regulator. When we cycled the pump the regulator kicked open and returned the fuel. Mine will not do that with the same exact regulator. WTF!! Why won't the regulator open? I tried applying vaccum to the regulator while cycling the pump and it still won't open the reg. I'm stumped.
What to replace is the question though? The regulator works perfect on a different car. I've already checked for blockages in the fuel rail and lines. Also, my Aeromotive is doing the same exact thing. Works on a different car but, not on mine. I just don't get it.. I apprectiate the help though. I work nights so, I'm about to hit the sack. Maybe I'll dream of a solution.
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obviously you installed the regulator wrong....
that sucks bud i thought for sure my reg would have worked for you...
want to use my whole rail and all and see if anything changes?
that sucks bud i thought for sure my reg would have worked for you...
want to use my whole rail and all and see if anything changes?
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Verdad Gallardo Well, I didn't dream of anything 
Could this be some kind of a fuel pump issue? What makes the regulator open, fuel volume? I'll prob. try getting the fuel rail from you tomorrow, it's worth a try.
Could this be some kind of a fuel pump issue? What makes the regulator open, fuel volume? I'll prob. try getting the fuel rail from you tomorrow, it's worth a try. 
Update Okay, I figured it out. I knew it had to be a blockage and I found it. When I pulled the fuel rail before it had alot of fuel coming from where the injectors were. I just wasn't convinced. I pulled it again and I disassembled the entire fuel rail. I found the blockage in the center of the front crossover tube. I suppose when I was painting all the engine compartment pieces while the paint was drying a dirt dobber decided to make the crossover tube its' home. I cleaned it all out and I have sufficent fuel pressure and I cranked it up and let it run for the first time. Damn it sounds good. Should have it tuned in the next couple weeks. I will do and entire build post to show the progress from start to finish with pics and hopefully a video. Thanks for the help.
