Couple of quick questions
 

Hey all,
Not new to the forum but haven't posted in a while, just got my new 7 on the road and had a couple of quick questions for the boffins:

1) The car idles at about 1500RPM or 1200RPM, drops to about 1000 when the A/C is activated. I am presuming the high idle is a TPS issue as it doesn't blow smoke, drives perfectly and starts easily when cold or hot. If anyone has any idea what else it would be, I would appreciate it. Going to do a full workup on it my next day off, change the filter in the airbox etc.

2) My fuel gauge does not seem to be reporting correctly. It was at full when I filled it up, 10km later it was at 3/4 full, and now at 100km it's at about half and it's sat on half for quite some time. I am thinking it may be a problem with the float or the fuel sender unit. I can tell you however the fuel light works (was on when I picked it up) but the gauge doesn't seem to like me much. Either that or I'm using a lot more fuel and I am a much worse leadfooted driver than I thought ;) Any help here would be appreciated before I just start replacing everything.

3) How often should a thermostat be replaced - mine seems to be functioning fine at the moment, but I am thinking when I head under the hood and replace my filters and everything I should consider replacing the coolant and the thermostat while I'm at it? Rather than leaving it until later and possibly risking an overheated and dead rotor. I have read the FSM which basically seems to say "replace it when it doesn't work" I'm hoping there's a more accurate way than that to tell.

Last one is the FCD that came with it - It is definitely running stock boost but it is however running a very large exhaust, I am presuming this is the reason it needed an FCD, if it just has an exhaust modification (there's nothing else I can see) should I check the fuel pump and everything installed and make sure they're bigger than stock, or should I be ok here. It's definitely not leaning out under boost or getting any sort of fuel cut, but I wanna be safe rather than sorry ;)

Sorry for the million and 1 n00b questions, but I wanted to make sure I'm getting it right the first time ;)

Thanks,
Sean

You have enough posts to post in the generational tech forums. You'll get a much larger audience there.

Since you didn't post the year of your car, I'm going to guess it's a 2nd gen.

Vacuum leaks, sticking cold start cam, misadjusted TPS, or a combination of all three.

The senders are non-linear, but it looks like yours has gone walkabout. Replace it. :)

If you don't know the last time it was replaced, replace it. Flush the cooling system and replace the rad hoses.

If the car is running stock boost, you don't need an FCD.

Wow that was quick ;) Thanks Aaron - love the website btw

And yes, it is indeed an S4 FC, was imported from Japan - when I first got it it was definitely running more than stock boost (10psi) but now it's running stock as when it was complied they removed (and nicked off with) the manual boost controller that was under the hood.

Will check it for vaccuum leaks as well as do the TPS test in the next couple of days, thermowax has already been removed so cold start keeping the idle up wouldn't be the problem and get the rad flushed with thermostat and hoses replaced.

Thanks,
Sean

very helpful posts