I just talked to Tuan after sending my unichip to him because my car is running dangerously lean lately. He mentioned that even with my modifications (test pipes, nismo exhaust, APS plenum) I shouldn't be running as lean as I am right now (12.5-13.0 a/f ratio in the higher rpms) and we narrowed it down to the fuel system. Whenever I would fill the car up and park it in my garage, the garage smelled like nothing but gasoline like there was a leak somewhere but I could never pinpoint where it was coming from.

To make a long story short if anyone who has a TT kit (especially APS) can direct me to a shop near the Atlanta area to have this checked out I would surely appreciate it. I'm going to contact CPRace as well to see if they can fix it.

 

i dont know about the 350z but i had the same thing with my g35.. pull up your rear seat or wherever your pump is and tighten it down again.. and check all your fuel lines!

 

How would this contribute to a lean A/F ratio??

 

obviously he is leaking fuel somewhere.. i dont know about the lean issue im just trying to help.. i had the same fuel smell in my car and this is what i did to resolve that issue..

 

hmm, ive never had the fuel smell before, i wonder if it is that the top metal piece isnt tightened down like paranormal said, and with a full tank it leaks out.

i know that the newer set of instructions about the fuel system mod included drilling out that restrictor piece on the fuel pump assembly, i asked APS about it because they didnt change it until after i installed mine. they said it would cause the car to run lean if it wasnt drilled out. but i didnt do it and i know most others havent either, and i my afrs are about 10 at wot. dont know if that is your problem, but is something that should be looked at.

 

 

yeah I have a G35 too, I'll probably take a look at it after work today

 

ok so what exactly should be tightened?

 

I have the AAM fuel return and I have the same problem. I don't fill the tank past 3/4's anymore because it will leak. Mine would take more than just tightening. It would need silcone or something like that. I had it fixed once, but it came back. Either way I don't see how this will affect the a/f.

 

Ive heard that replacing the fuel pump gasket is a must. Everytime you take it out it should be replaced. I replaced mine when I did my install and have no problems.

 

If you don't drop gas on the o-ring, it won't expand.

As for the lean condition, I'd check the Walbro fuel pump and check the voltage going to it, I have no idea what voltage should be present though. I'd assume ~12vdc. If that's good, I'd move on to checking out the injectors to make sure they're all working correctly.

Also, double check the vacuum line going to the fuel pressure regulator and make sure it hasn't come undone, and make sure the line isn't kinked where it runs along side the car under the trim.

 

for the O-Ring when contact with fuel it will expand. The trick is put the O-ring in the freezer for couple minutes then it will shrink back to its original size. I learned this from a 350Z member. When the O-ring expanded there will be a leak.

 

haha that's funny Jorge.. I do the same thing now with filling up the tank.. I did change my o-ring once.. I guess maybe it's time to do the freezer trick with yet another new o-ring..

--mike

 

oh no, im not saying that affects the afr, drilling out the hole is what i was talking about, the gas smell/leak was another topic.

 

I'll try and get the hole drilled cause I know my kit was installed long before APS released that