I own a 06' ralliart. Now I know that doing your own custom cai can sometimes be a bad idea, I strongly recommend now anyone to buy an aftermarket cai like aem or Injen.

well enough rant, ever since I put the custom cai to my car the next day in the morning when I start it to warm it, it makes a loud, weird sound (I really can't explain it, like it's going to break the engine). It happens for about 10 secs and then the rpms go up to 2k and the sound goes away and the car runs fine. It also happens if I turn off the car and leave it there 3 or 4 hours and start it again.

the CEL also appears from time to time, but I don't really have much of a concern about that. The only mods I have are the custom cai (aluminium pipe) and unbolted exhaust (although I have the cat and resonator).

can anyone help me, and does this thing have ever happened to anyone before?thanks in advance.

 

check the airflow censor, make sure you have it facing the right way.

 

A lot of times when you make your own parts, things start to happen. Chances are there's a leak or something, or most likely your airflow censor isn't connected. if you could post pictures up of the setup for intake you're using and it'll help us tell what's going on...
good luck
-Lee

 

These cars have an odd cold start idle. When I start mine after it's been sitting for several hours, it runs pretty choppy for about 10 seconds, then the rpms blip up to about 1100, then it settles back to its usual 700 and smoothes out. Mine has done it since new, and has had no problems yet at 68,000 miles.

The intake noise was more noticeable when I put on a CAI. Perhaps that's why you're hearing it now.

 

Check Airflow sensor, arrow should be pointing towards the back of the car on the 06(dunno about the 04-05).

Also, to reset the ECU

 

Mine does it. The choppiness goes away if I touch the gas too. Wonder why it does it...

 

it has to get everything working properly. all the sensors have to warm to a certain temperature before they begin to give readings properly. The noise is normal. I just put a muffler on my car an it is super loud during this period. The colder the car is, the longer this will happen. You should always let the car warm up before driving it, just like any other car. During the winter you should wait for the needle on the water temp gauge to begin to move, and then drive conservatively until the engine reaches normal operating temp. This is usually about ten minutes after it is started. We have aluminum parts in our engine, and aluminum doesn't do well with extreme temperature changes.

BTW, I made my own cold air intake, and it's fine. I wouldn't try to make a camshaft, but an intake is pretty simple.

 

What diameter is the CAI you made, particularly around the MAF? If it's anything but 2.5" where the MAF is, then it causes problems.

 

Well, I am using the stock location (cut off the air box) which I would imagine most people would do. It's kind of hard to make a mount for that dumb thing. Don't know what he is using for sure though, so good point.

 

Good advice. Though in -40 degree weather the needle usually doesn't budge until I start drivin

 

thats because you didn't sit long enough in your driveway. It will move, as soon as the coolant heats to a certain temperature. If you start driving before it moves go very gentle on the car.