420a fuel Problem!!!!

[matt98eclipse]

When I give my car full throttle I noticed my cars running really lean! I check my fuel pressure regulator at idle its set at 55 psi and at 6 psi of boost it only goes up to about 65 psi

I read the hahns manual. It says for intercooled state 2 the idle should be set at 45 and 6 psi of boost it should be about 85 90 psi!

I dont think its my afpr cus its almost brand new!

What do u guys think it could be causing this?

 

[DSMcrazy3]

What type of Fuel management do you have? If it's a 1:1 AFPR that's your problem. You need a 12:1 FMU in order to run boost on stock injectors. That way for every one psi of air, the fuel pressure is raised 12 psi.

 

[matt98eclipse]

Thanxs DSMcrazy3 that sounds like that could be my problem cus think it is a 1:1 ratio. Woundn't a big vacum leak cus it not to rise?

 

[Locke]

A boost leak in the reference line to the fpr would cause it to not rise properly, as it would see less boost than there actually is.

 

[matt98eclipse]

K thanxs guys for the help!

 

[DSM-ZERO]

if you ar erunning a aeromotive fpr wich is a 1:1 your static or "idle pressure", fuel pressure should be set to 80psi
so
with the 1:1 @ 6psi of boost will = 86psi of fuel pressure .

I ran a 1:1 and had a very high Static fuel pressure for a long time and had no idle problems or fuel echnomey problems either

 

[matt98eclipse]

k so let me get this straight I have a nock off " adjustable Fuel pressure regulator" that i bought off ebay! What should I set the fuel pressure at if i wanna boost at 8 psi?

What are your guys opinion?

should i just buy a OBX fmu or a sfmu?

 

[DSM-ZERO]

if your regulator is a 1:1 and you are using stock injs then set the static pressue too 80 psi .......

if you dont feel comftorble with your static pressure being that high you eiher have to get bigger injs or a SFMU.........
bigger inj will let you lower your static pressure because they are not going to require a high pressure to meet the fuel needs of your motor, hense you can lower your static pressuse...to around 60psi
A FMU will all you to kee pyou static pressure at stock levels because once boost starts to build the 12:1 ratio will raise the fuel pressue pretty high deponding on boost level


12:1 ratio of fuel @ 8pssi of boost = 96psi of fuel pressure

1:1 @ 8psi of boost W/ static set at 88psi = 96psi of fuel

 

[matt98eclipse]

thanxs man I ended up getting my friends sfmu that came with his hahns kit. Im not to sure how to set it since it doesnt have a fuel pressure gauge. I have never messed the bleeder valve! so any help with it would help.

 

[matt98eclipse]

What should i set my fuel pressure at?

walbro 255 fuel pump
stock injectors
sfmu
safc