I just bought my second S2K from a local who had done a lot of his own work on the car. It's an '07 with an Inline Pro sidewinder stage 2 kit. I'm enjoying the boost life, but I have a few questions.
He said he upgraded the fuel system to a returnless system, and had some sort of different fuel pump assembly in the tank, and that the fuel gauge only goes down to 4 bars, and won't go to empty. This obviously annoys me a bit and I want to know if it's a common problem, and if it's an easy fix?

Also, he specifically told me to keep VSA off at all times. Is there any reason for this? Would VSA kicking in during boost be detrimental to anything?

And the AFR does a constant sweep between 13 and 15 while at idle. During acceleration it drops to 12ish, and cruising it stays around 15 which seems pretty normal right? I'm no stranger to cars or even performance mods, but all this is new territory for me.

 

He upgraded the fuel system to a RETURN style system. 2nd gen AP2 comes from the factory with return less fuel systems. The fuel gauge should definitely be able to be fixed, but you have to pull the assembly out and its kind of a bitch.

No clue on the VSA.

AFR sounds fine.

 

1. The fuel level arm must be catching on something. I'd remove the pump assembly and see what it is. More than likely it's hitting against the pump or sock filter.

2. I'd leave VSA on. It may try to kick-in when you get on it, but for street driving it's a nice safety feature to have.

3. Normal. ARF gauges will sweep unless you're WOT. Get a proper wideband sensor if you want to monitor this properly. AF gauges are typically useless

 

Thanks. I'll pull the pump assembly when I get some free time. As for the AFR, it's an AEM wideband system. I just didn't know if the sweeping idle was normal. Also, I noticed yesterday that the idle likes to dip every once in a while, just a little, to where it becomes rough enough to shake the car. I've looked through the Flashpro calibrations, and the warm idle is set to 900 rpm. I'm assuming the idle quality is due to the bigger injectors? Would raising my idle slightly make it smoother?

 

Depending on your injectors most aftermarket ones will make your car do that at times unless the idles above 1000rpm. As far as the vsa maybe he is telling you that because it just kick in since the tires are going to spin. If your not going to get on it, leave it on.

 

The dip in idle may be from the radiator fans turning on does it do it when warming up? Or only after the car has fully warmed up? Mine dips when the fans kick on initially.

The afr swing really is all in the tune. Mine personally swings between 12.5 and 13.5 when idling. But I've seen others that stay between 14.7-15.

 

What injectors are you running?

My ID1000's dont dip or make the car rough at idle. There may be an occasional drop when the AC compressor kicks in, but it recovers and not enough to make the car shake.

 

They're ID1000's. It does dip when the fan kicks on, but it's not always because of that. It's not enough to where it feels like the car is going to die, just kind of annoying. Maybe it's idling too rich? I plan to get the tune checked out eventually.