I have a s5 intake swap with a rebuilt engine.
everytime I start her up she revs but won't hold idle and everytime I rev it it looks like it's trying to do the coldstartup feature but it's like she won't hold it.

After doing this two or three times the car just starts and shuts off.
I've tried moving all sorts of things around unplugging and running straight hoses bypassing the bypass air solenoid.

I also found a weird black grease on the side of the thermowax that goes to the engine.

can someone shed any light?

 

The computer may need to be reset by disconnecting the battery. I do it for 15 min. You changed the air intake. The computer thinks you still have the old one. This may or may not be your problem, but it is a free and easy test. And should be done.

 

gonna try it now

 

Is your AFM plugged in?

 

i didn't work, so I swapped in my s4 bac and it did the same thing. I am thinking about going with a megasquirt and itbs but I really need to get the car going now. Any other input.

any yes my afm is plugged in, otherwise the car wouldn't start.

 

If the AFM is unplugged, the car will start and shut off a sec or 2 after that.

 

it's not unplugged

and I just bought all the things I need to megasquirt tonight