I need some help from anyone in the NOVA/DC/MD/PA(H-burg or Philly) areas. I'm still trying to work out kinks and figure out why I lose Fuel Pressure while spraying. I have a stock Fuel Pump that has about 83k miles on it but, I think that its a Nitrous bypass valve Tee issue.

HELP HELP HELP

 

What shot and kit are you running? With that many miles, it might well be your fuel pump. Another culprit is the stock FPR. As far as your lines go, make sure none of yoru vacuum lines have any holes in them, and make sure you use zip ties on all the lines. My vacuum line at the T-fitting always wanted to come off, even after I zip tied it, I had to use TWO of them to hold it on! You could hook up a vacuum gauge, check and see when you spray what the initial pressure is, if it starts going down, you have a leak, if it stays even, then your fuel pump or regulator is going out. Hope this helps.

 

Right now I'm just trying to tune the 70 shot. After looking at some pictures of the vacuum line set up. I'm thinking I might have the T set up sideways. I think I have the bypass valve running off the NOS regulator then the left side of the T is to the vacuum source then the right to the FPR. I was looking at pics off of another thread I think it is set up wrong. I'll take and post some pictures in the morning.

 

Hmm, stock fuel pump might not be able to support the 70...

 

I am having a similar problem with my system, my fuel pressure doesnt fall off but I can't get it to go any higher no matter what jet I have in the bypass tee, I have run the vacuum line straight from the nitrous pressure regulator to the FPR and I still get the same fuel pressure, I even took all my solenoids out and took everything apart and put it back together and bench tested it for leaks. I have it narrowed down to either the NPR or the FPR but I need a way to test them, any ideas?

 

Sounds like that's your problem:

http://www.ericj.org/maxima/img/nos/nos_fpr_tee.jpg

You want the bottom of the tee (with the bypass jet in it) connected to the existing vaccum line going to the FPR. Then one side of the tee goes to the FPR and the other to the NPR.

That would explain just about all your problems.

 

I agree with mtrai, I think it's probably the fuel pump that may be the problem. Unless as you speculate, and have the bypass T backwards, the stock fuel pump usually likes to fall on it's face when the system is initially engaged due to volume. The stock pump will not keep up with the demands of higher shots because it lacks the ability to provide adequate volume.

I would check, as others suggested, the install first. If everything is connected properly and problem still persists, it's probably time to look into the fuel pump.

 

Ok I have my Bypass T going towards the Vacuum. Would a vacuum leak anywhere in the system (engine) cause a problem? I used to have a Vacuum guage set up in the car and I've taken it out but can hear the line hiss when I'm idling. I've meant to do something about it but I haven't as of yet.

http://www.max-performance.net/109-0990_IMG.JPG