I was having some idle surging issues with my S5 NA since I bought it. I fought the battle for a good 10 months and finally decided to take it to Tito Ramos at Alamo rotary. He played with the throttle stop and idle air screw on the TB and got it to stop. Unfortunately one problem still remains. The car will only idle at a calm 750 if I slow the Engine down somehow. For example, if I come to a red light and push in the clutch before the engine slows down, the car will idle at a rough 2000 RPM. When at a stop, if I hold the brake and drag the clutch, slowing the engine down, sometimes it will stay at a nice 750. Vice versa, if I have it at a 750 idle and I barely give it any gas (enough to bring it above 1100, it jumps to the 2000 RPM idle. Yesterday I removed the throttle body to clean it very well and make sure that nothing was getting stuck (and nothing was). I also put WD40 on all the springs and hinges, and there was no change. Any help would be appreciated, I do not want to let the idle demon get the best of me.

 

I believe the timing changes when the idle is close to 1100 so if you're playing w/the pedal to bring it to that level then the timing is going to change and it would likely affect the idle speed. And you also might want to make sure the clutch switch is working properly and sending the correct signal to the ECU. On an S5 pressing on the clutch and activating the switch is supposed to send a ground to the ECU pin related to this switch. And there is also a clutch switch on the brake pedal (at least that's the way it is on an S4).

 

I will check timing again when I get home. Thanks.

 

I'm saying when you play w/the throttle and raise the rpm close to 1100 the timing automatically changes. I'm not saying it does this because you have it set incorrectly but this is a function of how the ECU reacts to the given situation.

 

It shouldn't stay advanced though right?

 

I had the same problem, readjust the TPS and redoing the idle according to the FSM fixed it

 

No, but if you're playing w/the brakes and clutch then the ECU will want to compensate for the load and keep the idle from dropping and doing this before the engine is fully warmed up just complicates matters.

 

Okay. I took off the TB again today and adjusted EVERYTHING per FSM. This includes fast idle cam, fast idle clearance, primary clearance before the secondarys open, and alas the TPS. it is working better now. It's a lower idle. Still a jump as described before, but it's almost negligible. Like 700-1000. I really hope this can help someone out now.