I rescently built a S5 NA motor and did a large streetport during the build.
After install and longblock assembly I could get it to idle, but after about 30-60 seconds it wanted to surge and die. After numerous adjustments to the throttle body, TPS, and installing S5 turbo injectors and an FD fuel pump the problem was still. I installed a new TPS and set it to FSM spec and the problem only got worse.
The only way i could get it to run better and idle was to set the tps way out, tricking the computer to think the throttle was out, and giving the engine more fuel in compensation for the much more than stock amount of air the engine is getting. I also might add I have a ported and modified throttle body on the engine now as well as 3" aluminum intake piping, and emmisions delete.
So after all of this. I came to the conclusion that I am in need of either some sort of piggyback system that will deliver more fuel to my Large streetport 6 port engine or a stand alone system.
What are my options?

 

I do have a HKS F-CON, but its for a S5 TII.
I was thinking along the lines of a SAFC.
Would I be able to tune in more fuel with this?

 

is your fuel pump relay working correctly? or is it hard wired to the key?

a safc will not help it stay running at idle. there is something else going on, vac leak maybe?

 

rTeK!

 

+1 on the vacuum leak, especially if it is surging or idling high. Check that first.

 

Yes resiator and relay are working fine. I am going to check it over this weekend for vac leaks.

 

Doing some research on rtek this weekend.

 

+1

i'm all for going standalone, but it won't solve the issues you describe. i'd say work everything out first, then go standalone.