I changed my fuel filter (installed a 300z filter) and changed both rubber hoses that attach to the filter. I still smell gas after the car has been sitting awhile , but it clears up after I drive for a little while. I also removed the gas cap after the car was sitting awhile and there was no pressure release hissing sound. The CEL hasn't come on so I'm guessing the EVAP is ok. The only things I have narrowed it down to are an improper installation of the fuel filter or a leaking return line. I've tightened all the fuel filter hose clamps to the point that it is squeezing the hoses and there is a slight bulge on either side of the clamp.

Any thoughts? is there any tricks to installing the fuel filter, ie straight-forward removal of hoses and clamp on new ones? There isn't any kind of seal ring that i have to put in is there? Are there any other rubber fuel lines that are under pressure and are located in the fuel filter area? Is the EVAP under pressure?

Any other ideas?

 

I'm a bit confused to why Max owners are running the 300ZX fuel filters. I know it's larger capacity, but it's not going to do anything for performance. Maybe your problem is that the nipples on the 300ZX filter are larger than the stock nipples therefore it's creating a small leak. You say that you smell gas, but do you see any gas leaking? Does you car smell like gas all the time, are you on a garage when you smell gas, are you letting your car warm up? I'd say go back to the stock fuel filter. This will most likely get rid of your problems.


Dave

 

You have a leak. Before you start your car in the morning or when the car is totally cooled off, open the hood. Then start the car. Then carefully inspect the rubber fuel line connections to determine which one(s) are leaking. Typically when the car gets old the rubber lines are too brittle to seal very well. If it's still leaking at the filter connections, filter connectors might be too small.

 

How do I inspect them? what do i look for, a liquid leak? I've been staring at those lines for the past week trying to see a gasoline drip but I can't find any. Also how many gasoline pressurized rubber hoses are there in the front, just the 2 on the filter and the 1 return line or are there more i need to look at? Is the return line the same 5/16 inch tubing as is on the fuel filter? And what do you mean by "connectors?" Are you referring to the tube and filter interface? it was quite a snug fit. The tubing I used is actually a hair smaller then the old tubing I removed. I originally installed a Fram version of the stock fuel filter and had the problem. I thought going to the nissan Z filter would resolve the problem, but it didn't.

thanks!!

 

I don't see the confusion. Start the car when cold and follow the fuel lines starting from the inlet to the fuel filter then to the rail, along the rail and to the return line. If you smell gas, there's a leak. It could be the evap or whatever canister also.

 

I realize there is a leak. I realized that about a week ago, and I am trying to isolate it, which is why I'm asking all the questions. The inlet and the return lines are so close together that i cannot smell which line might be leaking. what i do know is that I'm leaking and not holding pressure, therefore it is most likely within the fuel filter lines or the return line. My question is: is there any other pressurized rubber lines that I have not accounted for? Is the EVAP under the same pressure that the gas lines are under? If the EVAP is not under that same pressure, then i can rule it out for now.

Cheers!

 

I just installed the 300zx filter on mine friday, the connectors are the same size as the max and it clips into the old filter holder quite nicely. I also installed the walbro pump and a gauge and I have no gas smell so you definately have a leak.
Did you change the clamps when you installed the filter? Don't use those useless hose clamps with the ring and slots cut in them. Get clamps made for fuel lines.

 

People use the 300Z filter because it lasts longer because of the larger surface area, not because of any performance increase. That would be silly.

I have one on my car....the hose nipples were exactly the same size as the stock filter, and I have no leaks.

And I only have to change it half as often.

IanS

 

T style hose clamps.

 

hmmmm......that might just do it. I did use the hose clamps with the little slots in it. Is that a bad thing or are they just not as effective? I'll try that tonight and we'll see what happens.

 

Mango those clamps with the slots are no good believe me, they have sharp edges and are not as effective as the T type, the others cost more but work much better.
Before I get flamed, the slot type do work if you tighten them just enough and no more because they can cut into the rubber gas line, problem is, that is a very fine line and not too many folks can do it unless they are doing it all the time and used to the feel of them. The T type either strip or tighten to max and do not cut the line.