funny sound when accelerating

kbobob · Post by **kbobob** » Wed May 14, 2008 9:24 pm

hey guys, I have been trying to figure out whats going on with my 01 atx.

The car seemed to be down on power lately and has a funny whispy sound when accelerating, right now i am suspecting a vacuum line and /or throttle body could be the issue. when on the gas it gets louder as you give it the gas and goes away as soon as you let off the gas.

lately I have been trying to get all the maintenance and repairs done that I know how to do or figure out how to do.

-atx - filter and new atf +4 and tightened a couple loose clamps
-swapped coil pack and injectors with ones with a lot less kms on them (was just messing around to see if it made any difference...didnt really expect much out of this)
-swapped my aem cai off for the stock air box
-took the intake manifold off and cleaned it out, it had oil in the bottom of it (small pipe of the cai had oil in it too)
-noticed cracks in the valve cover around where the pcv valve screws in, replaced the valve cover and installed brand new pcv valve.

so would anybody have any clues what is causing this...i looked at the tb briefly and didnt notice anything other then the rubber cap on the one said(facing the front) had fallen off, so i covered the hole and its still making the sound.

I know there is a normal whistle that the tb makes, its really noticable with the cai, not as noticable with out it, but this is a whispy/raspier sound. Now having done all of the stuff i did, i have noticed some of the power is back......but still has that sound. I am not really suprised by this.....its an 01 with 193,000kms on it......

tommorow i am going to look at the tb better and get some cleaner and try that....maybe i will be lucky and find a cracked hose or something.

thanx for any input eh.

Post by **occasional demons** » Wed May 14, 2008 11:01 pm

Could be your cat. converter also. When they get plugged they can make a hissing sound when you accelerate. The back pressure could make your intake louder also as the engine will "bog" a little more, so the intake has a little louder growl. Hard to tell without hearing it, but that's what came to mind first. Edit: Eh

aperson · Post by **aperson** » Wed May 14, 2008 11:24 pm

Check for leaks in the bellows tube if you are using the stock one.

kbobob · Post by **kbobob** » Wed May 14, 2008 11:31 pm

hmmm....i did swap out the cai to make sure it wasn't what was leaking and put the stock air box and resonator back in, the car is pretty darn quiet.

i am hoping its not the cat, but I guess it could be worse, i have another one in my garage, I just wouldn't look forward to swapping it out.

is there any way to test this theory, like should the cat be extra hot, funny exhaust smell, can i pull the upper 02 sensor and run the car and see if it changes at all.....i dunno ...any ideas

i mean it does seem to be running a little rough, i have put in new plug wires too.

i will look over the vac lines and clean the tb out this weekend and pray its this.

aperson · Post by **aperson** » Wed May 14, 2008 11:43 pm

But does the CAI you have use the stock bellows tube between the throttle body and intake? Thtas the tube I'm talking about.

If the cat is clogged then it will be glowing red after a drive.

Post by **occasional demons** » Thu May 15, 2008 12:03 am

aperson wrote:But does the CAI you have use the stock bellows tube between the throttle body and intake? Thtas the tube I'm talking about.

If the cat is clogged then it will be glowing red after a drive.

If the bellows tube had cracks it may raise the idle due to vacuum leaks. The cat doesn't always glow, it just depends on how far along it is. But I don't know how well it would run with the upstream o2 out. It would wack the PCM due to the feeback or lack of. The only sure way is to pull it off the manifold and then drive it the o2 mounts in the mani, so it won't throw a CEL. Not what you wanted to hear, I'm sure.

kbobob · Post by **kbobob** » Thu May 15, 2008 12:23 am

i was using an AEM cai.....with its bellow tube....it made this sound with that on,....then i switched to the stock setup, with the original bellows tube,...same sound...

i may take my car for its etest..haha....I will need a valid one for august, and they are good for a year, i guess one way to see if the cat is working is to do my etest early eh.....kinda kills two birds with one stone, would give me a clue if the cat is ok...and would get my etest done.

I'll be honest, with the hood open the sound doesn't sound like its coming from behind the motor, it sounds my likely to be the tb or a vac line to me......but having had cracks in the plastic valve cover all around my pcv valve inlet does have me wonder if the pressure was getting high in there....kinda curious what caused it to crack like that

Post by **occasional demons** » Thu May 15, 2008 7:58 am

The cracks in the valve cover are from heat/age. As long as the PCV system is functioning there shouldn't be pressure in the crankcase. If there was excessive blow-by the inlet hose would blow off the rear of the valve cover or your air box would be full of oil where the air filter is. In a CAI you would have oil before the TB.

kbobob · Post by **kbobob** » Thu May 15, 2008 9:04 am

well...when i had the cai on i had oil in the bottom of intackmanifold, on the inside of the bellows and a bit inside the TB

aperson · Post by **aperson** » Thu May 15, 2008 11:48 am

Thats normal for a Neon. It's because the PCV valve is on the side of the valve cover instead of somewhere else.

asanti · Post by **asanti** » Thu May 15, 2008 12:39 pm

kbobob
2GN Registrant

Age: 29
Joined: 17 Aug 2004
Posts: 60

2001 Chrysler Neon LE

Post: #9 Posted: Thu May 15, 2008 9:04 am Post subject:

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well...when i had the cai on i had oil in the bottom of intackmanifold, on the inside of the bellows and a bit inside the TB

Cheap quick fix: Catch can.
More expensive, time consuming, + Permanent fix: bore out the oil return lines in the block + the the oil pickup tube.

Later
Allex

kbobob · Post by **kbobob** » Thu May 15, 2008 2:50 pm

ah...the oil in there wasnt bothering me, i knew it was a normal thin, just figured i would clean it out and look for leaks at the same time.

oh well...i will shoot the tb with cleaner tonight and have another look around..and hope i find it.

Post by **occasional demons** » Thu May 15, 2008 11:00 pm

DO NOT use carb cleaner on your TB, it will f*ck it up. There is a flow enhacing coating on the inside that carb cleaner will eat. Use simple green, Castrol super clean, or dish soap. IIRC it is even labeled on the TB.

kbobob · Post by **kbobob** » Fri May 16, 2008 12:21 am

yup...its labelled on the sensor not to. i cleaned it up and ran a can of this engine tune up stuff from crappy tire in a vacuum line.....yeah yeah..i know i was flirting with trouble......when it was all said and done the car is running super nice now, i did pull my plugs after i ran that crap through....they got gummed up from it, but i was replacing them anyway. anyways, no vac leak found, i do have a hole drilled in my tb to help with the idle undershoot problem my car had....long story ...but thats the fix that worked.......i beleive its what is causing the whistling, i will play with that when i get a chance, maybe cover the hole and try it ......i smelt the exhaust, no rotten egg smell, the cat wasnt glowing and didnt seem any hotter then normal....and no hotter then my gf's 05 cat....so i dont think its that.....i pulled the oil cap off with it running......doesnt have a lot of blow by....so...the quest to find the whislte is still ongoing.....