Hello everyone..

I have a 03 supercharged 350z, it has the 3.33 pulley on stock fuel pump and injectors. It currently has a AEM fic installed.

The problem is that after 5k rpm the car afr leans out to 18s, I already have the fic on +100% fuel and it wont richen up.

If i take the gas pedal out a little (95% or so) the fuel richen like pig to 8.

So something tells me there is something wrong with tps or similar? i already calibrated the tps on the fic and same issue...

Any ideas? Thanks!

 

stock fuel pump and injectors? Lol.

 

Should be more than enough for 5 psi

 

You didn't mention if it's always been like that or only recently. More info pleeeeeeez

 

I just bought the car, the previous owner was able to set it fine but a pipe from the intercooler was bent, so he changed it and never retuned.

So we tried tuning and this happened. other than that it randomly threw me a tps code once and it hasnt done it since.

 

Never seen a 350z tuned with AEM before. I think this was discussed once or twice before, and if my thoughts serve me right it was unsuccessful. Get Osiris or a Utec. Good luck.

 

hate to be captain obvious, but you dont have enough fuel. combination of too small injectors and too small fuel pump. i'd say injectors 1st though.

 

Are you still using the aux pump provided with the vortech kit? Stock fuel system + aux pump is more than enough fuel for 3.33 pulley. My guess is the aux pump took a dump.

 

+1 on the aux pump, sounds like it isn't working, maybe.

If he previously had a boost leak/blockage ('bent pipe'??) he might have been able to tune it but now that it's flowing better he's out of fuel.

 

The stock fuel system+ aux pump/fmu can flow enough fuel to stall a car running the 3.33 pulley. I still vote aux pump

 

just ordered a walbro 255 today, also getting bigger injectors since i bought a 3.12 pulley.... let hope the pump makes something, the car has the vortech FMU

 

im not sure it came with an aux fuel pump. i only see the oem fuel regulator and the fmu.. is the aux pump in the tank too?

 

aux pump is not in tank. Look near the FMU. Vortech install instructions show it near the oil pan/front sway bar.

 

Ill check it first thing tomorrow.. i guess it makes some kind of noise? how do i know its actually working?

 

it's a silver cylinder looking thing that will be bolted to the crossmember near the blue FMU unit.

If you don't have one or it quit working (the power wire to the aux pump has a fuse on it) then it would be exactly the problem. The vortech FMU is a rising rate so as the fuel pressure increases on only the stock fuel pump without an aux pump it would just kill all flow.

I don't even know if the AEM has a set rpm point with a positive switch to turn on an aux pump.

best thing is scrap the crappy vortech fmu system and run larger injectors and walbro. I would even go as far to say getting a 400$ basic return system from CJM would work even better.

 

I agree with binder, since you already have a nice ems. Get injectors and the walbro and be done.

 

wait wait, i never said that was a good ems. I actually think it's a horrible ems but if he is going to use it then all he needs to fix the current issues is walbro and injectors. I truthfully would go with a return fuel system if it was me since they are so cheap for a base model now ($400).

just wanted to clear that up.

 

Hah!

Actually though, I have been using the vortech fuel system + injectors for 5 years now and it has never let me down. I think people get down on it a little too much, it is pretty crude but it works great for modest power.

 

you're lucky. I had that shitty diaphragm in there fail and also if you ever pay attention to fuel pressures it's a crazy high rising rate.

Stock is 7:1 rising rate so for every 1lbs of boost it rises 7lbs of fuel pressure. SS box is setup to kick on the aux pump rising rate at 5psi so if you are running 10 psi you have 5psi of raise which is 35psi of fuel pressure added to the stock 3.5 bar (52psi) so that's 87psi of fuel pressure.....WAY too much fuel pressure. At the 14psi of boost i was running i was pegging my fuel pressure gauge at 100psi which puts too much stress on a walbro pump and decreases it's output.