Fuel pressure drop

[PDD_EG9]

Hi Guy,
I just convert my car to EG9, and I need somebody advise on why my Fuel pressure drop when ramp up ?? Thanks if somebody can help on this !!

 

[rizal_eg9]

Hi dude,

Check out the fuel regulator on the fuel line. Chances are the there is a vacum leak and thats why the regulator cannot maintain the pressure. A normal fuel pressure should be about 3.5 bars.

 

[PDD_EG9]

oh..thanks. I will check on it. somebody told me is weak of fuel pump, they recomend me to change EVO 7 Fuel pump at RM400, do you think it work ?

 

[EFN]

oh..thanks. I will check on it. somebody told me is weak of fuel pump, they recomend me to change EVO 7 Fuel pump at RM400, do you think it work ?

The reason is quite simple - B16A uses BIG injectors (280CC) and when you rev up the Fuel Pump that you use right now is not spooling fast enuff to cope up with those injectors - Your Fuel Regulator is perfectly okay. First thing you should do is to upgrade to better Fuel Pump that can support 280CC injectors - any BOSCH, GSR, H22A or VR4 Fuel pump will do.

Stock Fuel Pressure for B Series is 30PSI (2.2 BAR) at Idle with Vacuum and 40PSI at Full Throttle.

Hope this helps

 

[wild_boost]

Hi dude,


try to swap other fuel pump higher flowrate than your.
lookslike your fuell pump can't cope with current setup...


Rgds

 

[ryucky81]

hi. if the fuel gauge move up n down wat happen har? battery weak? or other issue. pls give some advice. really appreciate.

thanks and regards

 

[rizal_eg9]

Standard B16 A only run 240cc injectors saturated type. 280cc injectors for vtec engine is on H22A.

Form my view, the pump is running at constant speed because it is only using a relay. It is just on/off. So the only thing that regulate the pressure is the fuel pressure regulator. Even if the pump is flowing more fuel but the return line is wide open, it will not hold the pressure in the fuel rail. Stock pump should be able to support up to 75psi at rail pressure.

In any case, diagnose with the basic and cheap thing first.

Just my thought.

 

[EFN]

A very simple test first - after idling for a while, shut down the engine and see how fast the pressure drops - if it drops immediately then the Fuel Regulator have a problem with weak Diaphgram and Spring - could be oso a sign of weak Fuel Pump at which the rotor blades will reverse immediately when power is off (supposedly the pump will hold tight the fuel content between the hoses and the fuel rail when it is switched off)

And oso could be Fuel Pump relay is not wired properly as rizal_eg9 stated.

 

[PDD_EG9]

ok, thanks a lot to all the sifu here....let me try it out !!