Nissan 370Z Forum - View Single Post

phunk · 12-26-2016, 03:40 PM

Running without the venturi installed or running it with the extra hole in it has ruled out the venturi as the source of your pressure spike. Unfortunately Nissan does not sell the venturi jet, so the only way to replace it is to replace the entire fuel pump housing. It will need to be replaced or repaired since the additional hole will either entirely defeat the venturi system or render it too weak for standard use. The car will fuel starve from not being able to recover fuel on the driver side of the tank.

All the black gunk/debris in the fuel pump canister is normal. I dont know where it comes from but its in every stock 370z fuel pump I have ever opened. The strainer being darker probably isnt a big deal yet, looks pretty normal for a well used one. It wouldnt effect the fuel pressure spike anyway as the most it could ever effect, if it were completely clogged up, it would restrict the pumps intake resulting a pressure loss rather than pressure spike.

Since your fuel system is stock, the only possible way for fuel pressure to exceed the regulator setting is if the regulator cannot vent out well enough, or if the regulator itself is damaged/clogged. You have eliminated regulator venting from the equation, so there are only 2 possibilities left. Your regulator is bad or clogged up, or the fuel pressure gauge is reading high.

I would replace the fuel pump module with another one since this is inevitable at this point*, and then if the fuel pressure is still too high according to the gauge, i would either try another gauge or I would just ignore it and write it off as the gauge just reads a few psi high.

*: unless you can find a way to plug that extra hole up with something that will not dissolve in gasoline. Such as machining a custom plug on a lathe and pressing it in, or something.

Another thing you can try, is drilling out the outlet on the stock regulator. I have never had to do this but I do not generally use a stock fuel system. All the cars I work with are using return kits. But I believe that Stillen has their customers drill the outlet on the regulator so it itself can vent better. This might be worth a shot as it could not hurt anything so long as you do not drill too deep into it.

12-26-2016, 03:40 PM	#43 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	Running without the venturi installed or running it with the extra hole in it has ruled out the venturi as the source of your pressure spike. Unfortunately Nissan does not sell the venturi jet, so the only way to replace it is to replace the entire fuel pump housing. It will need to be replaced or repaired since the additional hole will either entirely defeat the venturi system or render it too weak for standard use. The car will fuel starve from not being able to recover fuel on the driver side of the tank. All the black gunk/debris in the fuel pump canister is normal. I dont know where it comes from but its in every stock 370z fuel pump I have ever opened. The strainer being darker probably isnt a big deal yet, looks pretty normal for a well used one. It wouldnt effect the fuel pressure spike anyway as the most it could ever effect, if it were completely clogged up, it would restrict the pumps intake resulting a pressure loss rather than pressure spike. Since your fuel system is stock, the only possible way for fuel pressure to exceed the regulator setting is if the regulator cannot vent out well enough, or if the regulator itself is damaged/clogged. You have eliminated regulator venting from the equation, so there are only 2 possibilities left. Your regulator is bad or clogged up, or the fuel pressure gauge is reading high. I would replace the fuel pump module with another one since this is inevitable at this point, and then if the fuel pressure is still too high according to the gauge, i would either try another gauge or I would just ignore it and write it off as the gauge just reads a few psi high. : unless you can find a way to plug that extra hole up with something that will not dissolve in gasoline. Such as machining a custom plug on a lathe and pressing it in, or something. Another thing you can try, is drilling out the outlet on the stock regulator. I have never had to do this but I do not generally use a stock fuel system. All the cars I work with are using return kits. But I believe that Stillen has their customers drill the outlet on the regulator so it itself can vent better. This might be worth a shot as it could not hurt anything so long as you do not drill too deep into it. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph Last edited by phunk; 12-26-2016 at 03:51 PM.