I think i found the noise

bhw33191 · #1 06-14-2009, 07:26 PM

I think i was finally able to locate the weird noise i've been hearing from my engine. Rather then get a stethoscope i just used a piece of rubber tube, held it against my ear and got the same function for about 50 cents! Here's the picture of where i "think" its coming from. I believe its EGR related but i'm not sure what what to call the part.

toddman67 · #2 06-14-2009, 07:45 PM

That is an air injection manifold check valve. It allows the air to be introduced into the exhaust manifold through the invertor valve and air pump. Its pupose is to stop exhaust gases to return back into the air system.
Look up the part on the website of your parts store with the year, make, engine under emissions.

bhw33191 · #3 06-14-2009, 10:23 PM

Quote:

Originally Posted by toddman67

That is an air injection manifold check valve. It allows the air to be introduced into the exhaust manifold through the invertor valve and air pump. Its pupose is to stop exhaust gases to return back into the air system.
Look up the part on the website of your parts store with the year, make, engine under emissions.

If i took this check valve off and drove with it off (but not permanently off) would that be ok? Then itll be easier to see if thats actually where the sound if coming from but i don't wanna mess anything up by not having it connected.

toddman67 · #4 06-15-2009, 05:41 AM

You could temporarily disable the valve, but you will need to plug off both ends somehow. You might be able to pinch off the air hose going to the valve and try that first.

caffeineaholic · #5 06-15-2009, 07:49 PM

I recently had to replace one of my A.I.R. system check valves for my '85 caprice, for a time (day or two?) I ran the car with it removed and simply plugged the holes temporarily. I didn't have any problems but I wouldn't keep it off for too long because it may be possible that the air needs to circulate in order to keep the A.I.R. system from getting too hot (or the A.I.R. pipes). I'm not a mechanic though.

j cAT · #6 06-16-2009, 02:20 PM

that is the air pump check valve one on each side if the engine..
these valves need replacing every 10 years as the rubber diaphram gets rotten...

I believe, I thought that was an air pump issue,,,when these check valves fail exhaust, and mositure get into the belt driven pump which causes the unit to seize..

I had this come up on the 1983 and then on the 1996...

the 1996 has a electric motor driven pump so it was 200.oo to fix that all up,, with the 2 check valves...

one tip if you believe the cat converter is plugged you can use this pipe thread fitting to measure the exhaust pressure...

when removing be carefull you don't break those very soft pipes,,,use a small torch to loosen up first..use pipe sealant on the threads...

j cAT · #7 06-16-2009, 02:23 PM

Quote:

Originally Posted by caffeineaholic

I recently had to replace one of my A.I.R. system check valves for my '85 caprice, for a time (day or two?) I ran the car with it removed and simply plugged the holes temporarily. I didn't have any problems but I wouldn't keep it off for too long because it may be possible that the air needs to circulate in order to keep the A.I.R. system from getting too hot (or the A.I.R. pipes). I'm not a mechanic though.

the air pump supplies air to the cat converter so that on warm up its got a good amount of oxygen to aid the converter in doing its job...the air pump usually stops pumping after 5 mins or in AZ probably 5 seconds..

bhw33191 · #8 06-16-2009, 03:35 PM

Quote:

Originally Posted by j cAT

the air pump supplies air to the cat converter so that on warm up its got a good amount of oxygen to aid the converter in doing its job...the air pump usually stops pumping after 5 mins or in AZ probably 5 seconds..

So thats what the air pump does? I was wondering because i saw this other metal tube that came from the air pump and "it looked" like it went to the transmission. The thing is, i had my cat taken off so i'm wondering where this pipe goes to or if my mechanic just capped off the end since i wouldn't need it.

j cAT · #9 06-16-2009, 09:08 PM

Quote:

Originally Posted by bhw33191

So thats what the air pump does? I was wondering because i saw this other metal tube that came from the air pump and "it looked" like it went to the transmission. The thing is, i had my cat taken off so i'm wondering where this pipe goes to or if my mechanic just capped off the end since i wouldn't need it.

I forgot about that pipe to the cat converter /////ya that needs to be plugged...since no converter..

bhw33191 · #10 06-16-2009, 10:21 PM

Quote:

Originally Posted by j cAT

I forgot about that pipe to the cat converter /////ya that needs to be plugged...since no converter..

I took a look under the car today and found the pipe, and it wasn't plugged..and i actually think this might be the cause of the noise! Because yesterday i heard the noise and just so happened to touch that hose and notice it was vibrating in sync with that sound. I decided to pinch it and the noise went away. So i'll have to do another investigation in the morning.

bhw33191 · #11 06-18-2009, 04:27 PM

Problem solved. I put a pair of vise grips on the hose thats suppose to go to the cat and i never heard the noise again. But i have one more concern, if i plug this tube, will it hurt my air pump? And also, isn't it suppose to pump for only about 5 minutes upon cold startup until the exhaust temp warms up? If so, then i think i might have a faulty air pump or something because it seems to NOT pump when its cold and rather pump when its hot.

toddman67 · #12 06-18-2009, 05:39 PM

Considering that the air system seems to be working, I would recommend getting a new CAT and getting the vehicle back in compliance. When the systems are new and operating correctly, the car will run it's best. They don't install these systems with the idea to kill performance and fuel mileage. The car is set from the factory to have a balance of good performance, good fuel mileage and low emmisions.
As always, just my opinion.

j cAT · #13 06-18-2009, 06:43 PM

Quote:

Originally Posted by bhw33191

Problem solved. I put a pair of vise grips on the hose thats suppose to go to the cat and i never heard the noise again. But i have one more concern, if i plug this tube, will it hurt my air pump? And also, isn't it suppose to pump for only about 5 minutes upon cold startup until the exhaust temp warms up? If so, then i think i might have a faulty air pump or something because it seems to NOT pump when its cold and rather pump when its hot.

the pump is not needed now///you had the cat converter removed....

I had a pump one time seize on me///so rather than spend money on a 10 plus year old vehicle with high mileage I removed the pump blades which then caused it not to pump....this is because of the belt...

any pre 1985 vehicle no one cares about this any more....

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