Car won't run properly. R33gtr

[leung23c]

I will try lowering the fuel pressure but I don't think one of the injectors are leaking because I took out all spark plugs and they look fouled to the exact same extent. Also, when the car finally die and i look at the exhaust, I can visually see mist of fuel smoke from the exhaust pipe.....

What should I do if the cylinders are flooded?

[Skym]

From what I understand, with vacuum hose to FPR via little hose it drops fuel pressure at idle to stop engine flooding, stalling, as vacuum of engine sucks fuel out of injectors at idle. With less vacuum to FPR via little hose the FPR raises fuel pressure, as when engine is under boost the boost presssure prevents fuel exiting injectors, so fuel pressure needs to be equal or slightly above the max boost level engine is running (at intake manifold).

I would suspect 2x things, fuel pressure is too high at idle + not tuned for stroker bottomend. Correct fuel pressure problem, put PowerFC in and run the idle learn feature for 10 minutes or so, turning aircon on and off, etc (follow procedure in manual) and see if the problem is corrected.

[NismoS-tune]

3 bar!!!! Too high. Especially if that is with vacuum connected. I think mine wouldn't run until it was at 26psi, had nothing but rich running, stalling when I was above 35psi (no vacuum hose connected on the fpr to set the pressure, in case you didn't know)

[MattiasJacobs]

3 bar!!!! Too high. Especially if that is with vacuum connected. I think mine wouldn't run until it was at 26psi, had nothing but rich running, stalling when I was above 35psi (no vacuum hose connected on the fpr to set the pressure, in case you didn't know)

I run 65psi all the time on a hardwired fuel pump. Tuning issue?

[Skym]

There's a formula you use. If I remember correctly injector size plays a role in what pressure you run (part of formula). Factory fuel pressure is for factory injectors, factory boost level, etc. Also I remember there's a chart showing injector size vs pressure, etc (using formula) which makes it easier to know what to set pressure at. Best to consult a tuner who's done it many times over and knows the formula.

[leung23c]

Hi guys again.

I think if everything is in factory setting. I mean factor ECU, factory injector and factory air flow meter, 3 bar of fuel pressure without vaccum applied is default setting. SOMEBODY PLEASE CORRECT ME IF NEEDED!!!!!

As for my case, I start to think my engine is simply flooded -_-. How on earth can there be a puddle of gas at the exhaust when you start the car!? I have no experience with flooded engine. In fact I have not much experience with car AT ALL. All I had is a 1989 Volvo 240 all my life.

26 psi = 1.79 bar. Isn't this fuel pressure a bit too low? I just thought factor differential fuel pressure is 3 bar = 44.1 psi. AGAIN CORRECT ME IF I AM WRONGGGGGG

My car will be towed to CWS tuning next Wednesday. I am excited to see what their experty can figure out!?

[Skym]

Factory fuel pressure is 35.5psi at idle with vacuum hose connected and is 7.1psi higher without vacuum hose connected (block nipple on intake plenum with thumb or similar so there's no intake airleak) or when engine is on boost, where there's no vacuum inside intake plenum, as it's under pressure. Also 35.5psi + 7.1psi = 42.6psi before turning engine on (when there's no vacuum inside intake plenum).

From what I understand, it's the same stock FPR on RB20DET, RB26DETT (double check to confirm), except RB26DETT has 480cc injectors (someone on here said they were 480cc when flow tested, not the 440cc that many say they are), 190lph fuelpump and RB20DET is 135lph fuelpump, 270cc injectors (when flow tested).

If fit an aftermarket fuel pump the fuel pressure can be higher (into low 40's due to more fuel from bigger lph fuel pump and not exiting fuel rail due to small orifice inside stock FPR) and result's in engine running richer, more so at mid to high rpm where injectors are open more (ECU tune fixes that problem, as injectors are closed to compensate) and engine is on boost.

Another way is to get an adjustable Nismo FPR or SARD FPR and adjust fuel pressure with vacuum hose disconnected until get 42.6psi. But ask one of the sponsors / tuners to confirm, as it's usually best to adjust ECU tune than to drop fuel rail pressure on a injected engine.