fiestaturbo.com

[s1rsturbo]

does anybody no how to set up ofab i have got a fuel pressure gauge and a wideband afr is it just the idle screw u set and the fuel pressure regulator, i am running biege injectors and a msd custom chip but the car is hesitaing at about 3000 rpm any ideas thanks mike

[s1rsturbo]

Anybody got any ideas cheers

[georgiocat]

You need to alter the Co pot setting.what AFR value does the gauge show at full boost?I run mine at 3.3 bar fuel pressure,(with the vac on),and AFR value at full boost of 11.8-12.Idle screw is just to set the base idle,all the other cases of seting the idlewill be done via the ecu and iscv.So,you set the fuel pressure first,and then adjust the CO pot.

[s1rsturbo]

the afr on full boost in in the 10s mate also my fuel pressure is set to 3 bar with the vac pipe on i am running biege injectors aswell its hesitaing at about 3000rpm

[georgiocat]

10 is too rich m8 You are wasting fuel for no reason...What boost are you running?Perhaps it floods,or your turbocharger has lag and delays to spin and increase boost.Mixture related,14.7 at idle is ideally,12 is fine for boost,11.5 for more safety,although some people say it is not needed.Anything larger than 13 at full boost is a bit risky,especially for boost spikes.If you would like some more info,here is one of plenty of articles regarding tis issue:

http://autospeed.com/cms/title_Tuning-AirFuel-Ratios/A_1595/article.html

Generally,AFR values lower than 11-11.30 can cause hesitation,so a bit leaner will help response,but you must find the correct value to be in the safe side.I found that at the values I told you before,my setup spools fine,and temps are in the middle of the temperature gauge,even after some...."playing" on private roads with friends,if you get me
I have a Fezt engine,with T25 turbocharger running factory boost in my Escort.It feels like a bigger engine,no hesitation,and no breakouts in power.It boosts fully at about 2000-2200 RPM.

[s1rsturbo]

i am running about 16 psi mate i thought the fuel pressure had to be set a 3 bar on biege injectors shall i turn the fuel pressure down as the afr is to high on boost

[georgiocat]

Don't lower your fuel pressure.It is supposed to be 3 bar on factory specs.If you lower it down,it will affect all your fuelling.I would suggest to lower down AFR by turning clockwise the CO pot.Do it gradually and take it for a ride each time you alter it.Turn it one,ona and a half turn each time,it is a multiturn potentiometer,so it has precision on it's setting.clockwise leans,anticlockwise enrichens.

[s1rsturbo]

i thougth the co adjustment was just for the base idle, as on idle i am getting 14.2 afr but on full boost i am getting 10s and its hesitating at about 300 rpm cheers

[georgiocat]

No m8,Co adjustment sets fueling,it is the black potentiometer on the loom.If you trace it's wiring on the schematic diagram of the OFAB,it is connected on the circuit of the map sensor,so it is altering it's signal and feeds it to ECU from another input if I recall right,I haven't the schematic in front of me now...so it alters fueling throughout the rev range.Base idle is controlled by the screw on the throttle body,which regulates the amount of air bypasses the throttle plate.It's like pressing a bit with your foot the throttle pedal You set it once at 850 rpm with the ISCV disconnected and you forget it's existence after that.ECU controls the idling on all other phases through ISCV from that point.CO pot alters the map readings to ECU,and this regulates the fueling.

[fezzRS]

This might be old thread but with wideband helped me massively