Alright so I got an issue with cold starts. its a s4 turbo 2, rebuilt motor with like 2-3k miles, great compression, large street port, all emissions removed, even from the throttle body(secondaries removed). no AWS but I do have the AICV

Pretty much whenever I start the car it will fire up immediately then die, pretty much I have to hold the throttle open for a few seconds to get it to idle, my crappy narrow band O2 a/f guage says it lean, and as it warms it creeps to being rich as it gets to temp...

I have set the timing numerous times, I assume its right, I did it according to the FSM but when I take a timing light to it the marks are off the left, usally idles around 1300.....TPS is set correctly.

What could be causing this...

 

anyone?

 

Its the nature of the beast. Want it to fire right up and run every time? Put a stock tb on it and put alot of them parts you removed back. I have the exact set up and I always have to throttle it it start. Even in the summer.

 

What could be causing this...??

Did you eat anything from Taco Bell lately??? (J/K..)

listen to "the King".He is spot on,on this one.

 

well i mean I didnt have any emissions before I did the TB mod. and it was fine cold starting, and that on a low compression motor. I did the TB mod after getting a rebuilt motor.

 

What about the thermowax?

When you say AICV, do you mean the BAC valve?

 

sounds like your common vacuum leak. check your TID for cracks and cracking/missing vacuum caps.

 

it might be, but the TID is fine and my vac caps are fine. It might be a ecu thing, my narrow band gauge does says with very lean.

 

it takes about 5 minutes for a narrowband O2 sensor to warm up to giving a reading and even then it only reads within 1 point or so of stoich (14.7:1AFR) so technically it would read lean until warm, then read rich, then finally settle and give a measurable reading while cruising on the highway in closed loop.

in other words the narrowband is pretty much useless, the car won't idle reliably above 14.7:1 so it could be used to rule out a fuel system problem i suppose.

 

Hard Cold start is almost always the temp sending unit in the water pump housing. It tells the computer the car is already hot making it hard to start cold.