i just but a aftermarket intake on my 04 monte carlo. only other modification on it is a performance chip installed via iats. everything seemed to be fine until i put on intake. temp guage does not seem to be working or wont register like it normally did say 180 degrees or so. not its below the 140 mark. also at high rpms/higher speeds i hear a loud quick series of hisses. i know intakes can be a bit loud but this does not sound like a normal intake noise. anyone have a clue whats going on?

 

First off, what kind of intake did you get? I have an 03 SS and have the K and N FIPK and mine hisses, its a normal thing. the cone filter is huge. dont worry. The one thing that could really screw things up is that so called "performance chip" that you probably bought on ebay seeing as they are all over that site. if its what im thinking, it connects into the IAT (its just a resistor they sell at radio shack) and it makes a false signal to the PCM about what the air temp. coming in is. It does nothing for your car. the best thing you can do is take that resistor out, plug it into your intake, and if you want better results, buy an upgraded pcm off a legit site like zzperformance.com i've bought all my stuff from them and they are great. I hope you didnt pay 20 bucks for that resistor, you can buy it at radio shack for like .20 cents.

good luck, and if you have any other questions feel free to post it. there are a lot of members with an array of knowledge on the 3800 engine here.

 

i did get the chip off ebay but i actually have no complaints with the chip since i have noticed good results and the car has been running fine for about a week now. it is wired in with the iats next to maf on intake. put intake on today, drove about 3 miles. gave it some good acceleration going about 60 and heard a series of loud hisses like air was being released pressurized. let off accelerator and it quit. then noticed temp. guage would not register. must be something with intake or maybe the combination of chip and intake? read maybe coolant temp sensor went out, because my fans are kicking on regardless of engine temp. going to mechanic tommorow. anyone else have input? safe to drive until mechanic looks at it?

 

did you disconect the coolant temp sensor possibly?? that could do it and cause all those issues

also one thing you could try is to remove the chip and see if it still does the same things

 

If the coolant gauge isn't registering and the fans are always on then it's usually a problem with a bad thermostat causing the PCM to go into failsafe mode.

I couldn't say about the hissing you're hearing though.
Could be two unrelated problems.

-Riggs.

 

took it to a mechanic and they looked at it and test drove it with no problems seen. on the way to mechanic the gauge seemed to be working fine when yesterday it didnt seem to work at all. maybe it took time for the computer to adjust to the intake? the mechanic didnt hear any of the loud hissing like i did when he test drove it but i heard it once again when i gave it alot of gas and hit about 70. anyone else have any input?

 

One big thing you can do is check the intake for leaks. That "hiss" could be because of the intake. I know without a loud muffler, CAI can be heard sucking in air very well inside the car. Too much hiss could be a leak someplace in the connection.

 

As far as an intake "hiss" did you install a CAI or an intake manifold, if it's a CAI the hiss would be normal, it will be loud on a cold start up at idle and gradually taper off then come back when you open the throttle, the gauge is probably reading wrong/not at all due to a bad connection at the temp sender on the manifold or a shorted/open temp gauge wire, possibly you pinched or cut the wire when installing the CAI?

 

well, figured out what it was. the day before i had an aftermarket bumper put on the front. when they installed it a portion of the whell well was not attached to anything. so when i stated getting some speed the wind knocked that part back into the tire, flapping and rubbing making a very strange sound like a loud hiss.