WHAT IS AN A-I-R PUMP ON A CHEVY CAPRICE ENGINE?
Jeremy Kagan
noisy A-I-R pump on an '86 chevy caprice?
A mechanic offered to replace my noisy A-I-R pump for $75. My initial
inclination is not to fix something unless it doesn't or won't work.
Background: My engine rattles during acceleration (sometimes). When I use
premium gas, the frequency and level of the rattle is hardly noticeable.
So, I figured the timing needed adjustment. The mechanic adjusted the
timing, but said that the rattle is still there, and is due to a noisy
A-I-R pump. This is the first time I ever heard of and A-I-R pump.
He said it still works fine, it's just noisy. Ergo, I'll save my $75
until such time as I NEED to replace it. He said, it has something to
do with air & exhaust in the engine/catalytic converter (I am not quite
sure).
Can someone please post what is involved in replacing such a pump with
respect to physical labor, part cost (new and/or used)? Is this something
that a qualified mechanic should do, or can a ten thumbed sunday oil-changer
like myself do it? Does its noisy behavior indicate something wrong with the
pump that can have an adverse affect on my engine?
Any input would be appreciated.
Thanks,
Jeremy
Brian Golden
> Can somebody please enlighten me as to what is involved in replacing a
> noisy A-I-R pump on an '86 chevy caprice?
>
> A mechanic offered to replace my noisy A-I-R pump for $75. My initial
> inclination is not to fix something unless it doesn't or won't work.
What the air pump is, is a pollution control device that injects air into
the exhaust manifold so that any fuel that hasn't burned yet will before it
leaves the exhaust system. The AIR pump is help on by about four bolts, and
the tubes going to the exhaust manifold. It is not terribly bad to replace.
It might be a little tricky if the pipes going to the exhaust manifold are
rusty. Just pour a little liquid wrench on it and let it soak in, and it
shouldn't be too bad.
Or if your state doesn't have an inspection law, and you are not too
concerned about being legal, you can just take the damn thing off and
get a shorter fan belt, and plug the holes in the exhaust manifold. You
will get a little more power this way, because the engine will not have to
turn the AIR compressor. Either way, it is not terribly difficult.
Option three: Just disconnect the pully and get a shorter fan belt,
so that you can reconnect it come inspection time!
Mike Golden - mgo...@cwis.unomaha.edu
Mathieu J. Maessen
|> Can somebody please enlighten me as to what is involved in replacing a
|> noisy A-I-R pump on an '86 chevy caprice?
The air pump does exactly what its name implies - it pumps air! :)
Its purpose is to pump air into the exhaust system, either into the exhaust
manifold or into the catalytic converter, to make the converter work efficiently.
The symptoms you describe (noise) seem to indicate that the bearings on the air
pump are gone. You may risk seizing the bearings and breaking the belt driving
the unit.
As far as replacing the unit, it should be no problem if you've had any ex-
perience repairing your car before. You simply disconnect the hoses going to
the unit, remove the pump, install the new one, and reconnect the hoses.
--
Mat Maessen N2NJZ | mae...@rpi.edu
------------------------------- |-----------------------------------
The opinions expressed in this message definitely do NOT reflect the
views of RPI, Roland Schmitt, or BAPP
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(c) 1992 Fake-sig Co., Inc.
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Paul Heuer
<< stuff deleted>>
> Or if your state doesn't have an inspection law, and you are not too
>concerned about being legal, you can just take the damn thing off and
>get a shorter fan belt, and plug the holes in the exhaust manifold. You
>will get a little more power this way, because the engine will not have to
>turn the AIR compressor. Either way, it is not terribly difficult.
> Option three: Just disconnect the pully and get a shorter fan belt,
>so that you can reconnect it come inspection time!
>
>Mike Golden - mgo...@cwis.unomaha.edu
DO NOT JUNK THE AIR PUMP!!
The motors that use air pumps here in Oz apparently do not
react well to having the air pump disconnected. The after-market workshop
manual for my car (Gregory's brand) warns not to remove the pump or run the
motor without the belt even for short periods of time.
I must say, my first reaction to pumping air back into the exhaust ports was
"what a stupid idea, I'll soon fix this".
Now can anyone tell me *why* the air pump shouldn't be removed??
Cheers,
Paul Heuer (p...@aeg.dsto.gov.au)
--
Paul Heuer E-mail : p...@aeg.dsto.gov.au
Avionics Technology Phone : +61 8 259 6453
Air Operations Division FAX : +61 8 259 5507
Carl Smith
>s...@staircase.bae.bellcore.com writes:
>> Can somebody please enlighten me as to what is involved in replacing a
>> noisy A-I-R pump on an '86 chevy caprice?
> Option three: Just disconnect the pully and get a shorter fan belt,
>so that you can reconnect it come inspection time!
I don't think that taking the belt off is a good idea. I did that
and saw no significant increase in power or fuel economy. But a
few months later I noted that the pump was seized solid. It turns
out that the check valve was stuck open, which filled the diverter
valve and the air pump with the same black carbon that currently
coats the inside of my tailpipe (so my engine is out of tune..).
To fix the problem I took the pump off and poured various solvents
into it but nothing broke up the gunk. So I soaked it for a week
in brake fluid, which broke up the gunk. I then wrapped a cloth
around a drill bit, coated the cloth with rubbing compound and
polished the inside surface of the pump and the rotor. The pump
works great now. A new check valve cost me $14.95 and a couple
hours of trying to fit wrenches into a space no bigger than the
valve to replace. So, all in all it cost me $14.95 and quite a
few hours of work to get the system running again, just because
I thought it might save some gas & give me more power... I also
think that taking the belt off might have caused the check valve
to go bad in the first place, due to the larger pressure
difference.
--
------------------------------------------------------------------------
Carl D. Smith Inhale to the chief!
csm...@plains.nodak.edu
Brian Golden
> mgo...@cwis.unomaha.edu (Brian Golden) writes:
> << stuff deleted>>
>
> > Or if your state doesn't have an inspection law, and you are not too
> >concerned about being legal, you can just take the damn thing off and
> >get a shorter fan belt, and plug the holes in the exhaust manifold. You
> >will get a little more power this way, because the engine will not have to
> >turn the AIR compressor. Either way, it is not terribly difficult.
> > Option three: Just disconnect the pully and get a shorter fan belt,
> >so that you can reconnect it come inspection time!
> >
> >Mike Golden - mgo...@cwis.unomaha.edu
>
> DO NOT JUNK THE AIR PUMP!!
> The motors that use air pumps here in Oz apparently do not
> react well to having the air pump disconnected. The after-market workshop
> manual for my car (Gregory's brand) warns not to remove the pump or run the
> motor without the belt even for short periods of time.
>
> I must say, my first reaction to pumping air back into the exhaust ports was
> "what a stupid idea, I'll soon fix this".
>
> Now can anyone tell me *why* the air pump shouldn't be removed??
engine performance. It might be harmfull to your catalytic converter
(emphasis on MIGHT). The only possible explanation is that on modern
engines with an O2 sensor, it might throw it off. I don't see how an O2
sensor would even work on an AIR equipped car anyway, because it would be
fed straight air from the outside world, and it couldn't monitor the O2
left over after the engine like it is supposed to. I think that this is
just a ploy to get you to keep your emmissions control devices in tact,
and to keep emmissions parts manufacturers in bussiness. Just my $.02
Mike Golden - mgo...@cwis.unomaha.edu
P.S. I drove an '80 chevette with the AIR pump disconnected for three years
and actually gained a few HP. My brother's Malibu has the AIR pump
disconnected and it runs in the 15s on a bone stock 350.
Brian Golden
> In article <1993Jan20....@news.unomaha.edu> mgo...@cwis.unomaha.edu (Brian Golden) writes:
> >s...@staircase.bae.bellcore.com writes:
> >> Can somebody please enlighten me as to what is involved in replacing a
> >> noisy A-I-R pump on an '86 chevy caprice?
>
> > Option three: Just disconnect the pully and get a shorter fan belt,
> >so that you can reconnect it come inspection time!
>
> I don't think that taking the belt off is a good idea. I did that
> and saw no significant increase in power or fuel economy.
difference to another. ANY accessory attached to the engine is going to
draw power and lower fuel economy. This is why you don't see top fuel
drag cars with air conditioning! Also, it sounds like him pump is pretty
well shot anyway. I am just trying to offer a cheap alternative. Part
of the new "Screw the Earth" campaign! :-)
Mike Golden - mgo...@cwis.unomaha.edu
James W. Swonger
with the HC/CO in the exhaust. Your tailpipe may have an illegal aroma
and there's a small chance of fouling the cat more quickly if the mixture
is way off. There's a simple solution, of course.
Leaving an air pump connected but undriven may let exhaust gases flow in
the reverse direction - there's no air flow to stop them. This might cause
damage or crud to collect there.
Removing the air pump entirely leaves an exhaust gas path (from the exhaust
manifold(s) octopus to the air pump outlet) to the engine compartment. The
opening would have to be plugged tightly and nonflammably, or the entire
octopus removed and plugs installed in its place, or the octopus broken
off and the tube ends crimped and maybe brazed. Plugs are best, and the
air pump system can be saved in its entirety in case your locale goes
ecophrenic.
--
##########################################################################
#Irresponsible rantings of the author alone. Any resemblance to persons #
#living or dead then yer bummin. May cause drowsiness. Alcohol may inten-#
#sify this effect. Pay no attention to the man behind the curtain. Billy!#
Jim Vienneau - Sun Microsystems
>> Now can anyone tell me *why* the air pump shouldn't be removed??
>I can not really think of any reason why removing the air pump would affect
I don't know about the Caprice, but on my '82 Buick Regal with the 3.8L V6,
the AIR pump only pumps into the exhaust stream for the first 5 minutes of
engine start, then it just diverts the air into the air cleaner. It helps
cut down the emissions before the ECM goes into closed loop mode. When it
started to seize, I pulled the belt with no difference in performace or
fuel economy. (for the greenies out there, yes I'm going to replace it as
soon as it gets warm enough here to go junkyard roaming).
--
Jim Vienneau, Sun Microsystems Inc - Chelmsford, MA
Email: jvie...@east.sun.com Amateur Radio: WB1B
Good old Ma Bell (well old anyway): (508)442-0372
Wes Fujii
: I don't know about the Caprice, but on my '82 Buick Regal with the 3.8L V6,
: the AIR pump only pumps into the exhaust stream for the first 5 minutes of
: engine start, then it just diverts the air into the air cleaner. It helps
: cut down the emissions before the ECM goes into closed loop mode. When it
: started to seize, I pulled the belt with no difference in performace or
: fuel economy. (for the greenies out there, yes I'm going to replace it as
: soon as it gets warm enough here to go junkyard roaming).
There are several different applications of the AIR pump in the GM rigs.
One common application is to pump the air into the exhaust manifold during
open loop mode (warming up). This gets the catalytic converter warmed up
and up to temperature faster. Then, when the engine goes into closed loop
mode (engine warm, computer actively adjusting stuff) the air is switched
in the diverter valve to the middle bed of the catalytic converter. The
pump only absorbs 3hp, I believe, and when working properly you shouldn't
be able to tell that it's there.
The oxygen sensor is upstream from the closed loop air injection point so
it will not be affected by the AIR system.
REMOVING OR DISABLING THE PUMP MUST BE DONE WITH CARE! As other people
have posted, it is best to pull the whole AIR system, plug the manifold
openings and remove the catalytic converter. If you just remove the
belt, the exhaust gasses will make their way up the tubes, past the 1-way
check valves right into flammable rubber hoses and plastic diverter valve.
Engine fires are not uncommon when this happens and repairs are thus
expensive. For a mere 3hp, it's best just to keep the thing in working
order and reduce the tailpipe emissions.
WARNING! On some vehicles, the AIR pump also provides vacuum to some
accessories so depending on your engine, you could be disabling more than
what you bargain for!
Wes Fujii
________________________________________________________________
___ ___ ___
/ / / // /
/ /__/ // / A real motor is an Oldsmobile Rocket 455
/ HURST // / "This is NOT the new generation of Olds"
/ / / // /_______
/__/ /__// // ___ \
/ // / \ \ Wes "BANZAI" Fujii
/ // /OLDS/ / Boise, Idaho
/ / \ \___/ / we...@hpdmd48.boi.hp.com
/__/ \_______/
Jerry Bowman
The only reason not to remove it is that it ay be illegal in
your area, After all it is just an air pump pushing air into your
exhaust manifolds. If you only take the belt off exhaust can flow
back into the pump andbuild up carbon deposits. Then when you want
to reconnect it for an emmissions test it will not turn.
Bob Pitas
>mgo...@cwis.unomaha.edu (Brian Golden) writes:
><< stuff deleted>>
>
>DO NOT JUNK THE AIR PUMP!!
>The motors that use air pumps here in Oz apparently do not
>react well to having the air pump disconnected. The after-market workshop
>manual for my car (Gregory's brand) warns not to remove the pump or run the
>motor without the belt even for short periods of time.
>
>I must say, my first reaction to pumping air back into the exhaust ports was
>"what a stupid idea, I'll soon fix this".
>
>Now can anyone tell me *why* the air pump shouldn't be removed??
The reason is that most AIR pumps pump air to the exhaust ports during initial
warm up of the car, and then switch and pump the air into the cat-con.
This allows the cat-con to heat up faster, and helps cold-weather starting.
The engineers found that one easy way to make a fuel-injected car run rich
when cold (like the choke on a carbed engine) is to run air into the exhaust
stream up-wind from the O2 sensor, fooling the O2 sensor into telling the
computer that the car was running too lean. In reaction to the 'lean'
condition, the fuel injectors are pulsed longer, and more fuel is injected,
making for a richer mixture. If you remove the AIR pump, the car won't run
properly when cold and will start like shit.
>
>Cheers,
>Paul Heuer (p...@aeg.dsto.gov.au)
>--
>
>Paul Heuer E-mail : p...@aeg.dsto.gov.au
>Avionics Technology Phone : +61 8 259 6453
>Air Operations Division FAX : +61 8 259 5507
----------------------------------------------------------------------------
___
/ _ \ '85 Mustang GT Bob Pitas
/ /USH 14.13 @ 99.8 bp...@ctp.com
/ /| \ Up at NED, Epping, NH (Cambridge, MA)
"" - Geddy Lee (in YYZ)
Disclaimer: These opinions are mine, obviously, since they end with my .sig!
----------------------------------------------------------------------------
Bob Valentine
[previous stuff about AIR pump removal deleted]
>
> The only reason not to remove it is that it ay be illegal in
> your area, After all it is just an air pump pushing air into your
> exhaust manifolds. If you only take the belt off exhaust can flow
> back into the pump andbuild up carbon deposits. Then when you want
> to reconnect it for an emmissions test it will not turn.
Sorry, almost _ALL_ AIR systems have a built in check-valve, the
main purpose of which is to prevent damage to the pump and components
in the case of a backfire. If I disconnect it, I remove the outlet
hose and give a liberal squirt of oil into it, then spin it. AIR
pumps do like to sieze if they are disconnected and left....
--> Bob Valentine <--
--> rava...@mailbox.syr.edu <--
ajb...@ritvax.isc.rit.edu
>In article <1993Jan22.1...@colorado.edu> bow...@csn.org (Jerry Bowman) writes:
>[previous stuff about AIR pump removal deleted]
>>
>> The only reason not to remove it is that it ay be illegal in
>> your area, After all it is just an air pump pushing air into your
>> exhaust manifolds. If you only take the belt off exhaust can flow
>> back into the pump andbuild up carbon deposits. Then when you want
>> to reconnect it for an emmissions test it will not turn.
Which brings to mind a half-baked, wild, and probably foolish idea.
I'm positive people will tell me in great and excruciating detail
why it won't work.
How about setting up a diverter so that the output from the air pump could be
switched over to the INTAKE manifolds. Kind of a belt driven
mini-supercharger? With a switchable valve at the split point so you could
switch the air flow back to the exhaust manifold.
On the other hand, even if it could work it would probably be illegal.
Alex
Carl Smith
>In article <1993Jan22.1...@colorado.edu> bow...@csn.org (Jerry Bowman) writes:
>[previous stuff about AIR pump removal deleted]
>>
>> The only reason not to remove it is that it ay be illegal in
>> your area, After all it is just an air pump pushing air into your
>> exhaust manifolds. If you only take the belt off exhaust can flow
>> back into the pump andbuild up carbon deposits. Then when you want
>> to reconnect it for an emmissions test it will not turn.
>
> Sorry, almost _ALL_ AIR systems have a built in check-valve, the
>main purpose of which is to prevent damage to the pump and components
>in the case of a backfire.
But don't rely on the check valve to do it's job. Like I already
posted once, I pulled the belt of my air pump. People told me it would
seize, so once every couple months I would put the belt back on, fire
up the engine, and squirt a small bit of oil in behind the pulley where
it sucks the air in, then take the belt back off. But I forgot about
it and soon had a seized pump. When I pulled the back off the pump,
it was full of the same carbon that coats the inside of my tailpipe
because my engine is out of tune. I cleaned the carbon out of the
pump and got it working again. It turns out that my check valve
was shot, and the exaust was blowing back into the pump. It also
melted the plastic diverter valve so that it is seized in one
position, which I haven't got around to replacing yet.
>If I disconnect it, I remove the outlet
>hose and give a liberal squirt of oil into it, then spin it. AIR
>pumps do like to sieze if they are disconnected and left....
Doing this once when you disconnect it probably isn't good enough.
You should probably squirt a little oil in and spin it periodically.
Paul Heuer
>In article <1993Jan22.0...@dstos3.dsto.gov.au> p...@swan.dsto.gov.au (Paul Heuer) writes:
>>mgo...@cwis.unomaha.edu (Brian Golden) writes:
>><< stuff deleted>>
>[More stuff deleted]
>>{Stuff I said before deleted} (I hope this doesn't turn into a cascade :-)
>The reason is that most AIR pumps pump air to the exhaust ports during initial
>warm up of the car, and then switch and pump the air into the cat-con.
Cat-con?? What cat-con. I should have specified that my car is a 1982 leaded
(GM) Holden.
>This allows the cat-con to heat up faster, and helps cold-weather starting.
>The engineers found that one easy way to make a fuel-injected car run rich
>when cold (like the choke on a carbed engine) is to run air into the exhaust
>stream up-wind from the O2 sensor, fooling the O2 sensor into telling the
>computer that the car was running too lean. In reaction to the 'lean'
The "computer" in my car consists of a couple of thermally activated vacuum
switches that let you have vacuum advance once the motor is warm. No O2 sensor
in sight and still using a piece-of-sh1t French carby! Ahh technology - it sure
had our carmakers fooled for a while!
>condition, the fuel injectors are pulsed longer, and more fuel is injected,
>making for a richer mixture. If you remove the AIR pump, the car won't run
>properly when cold and will start like shit.
I think that the reason for not removing the belt from the air pump in my case
is that, with no air pressure from the pump, hot exhaust gases can flow into
the pump and possibly ignite the plastic and rubber parts of the pump
(thanks to some-one else for coming up with this reason). As far as removing
the pump altogether, I suspect that the police and/or road traffic board would
decide the car was not roadworthy.
Thanks for the info on *modern* air pumps though Bob.
Cheers,
Paul.
--
Paul Heuer | Phone : +61 8 259 6453 | Air Operations Division - DSTO
p...@aeg.dsto.gov.au | FAX : +61 8 259 5507 | PO Box 1500, Salisbury
| South Australia, 5108
|
Rick Inzero
>
>The air pump does exactly what its name implies - it pumps air! :)
Nobody's posted this yet, so here goes:
AIR stands for Air Injection Reactor (system). It was introduced on
Chevys in 1967, mandatory for California cars, optional on others.
>Its purpose is to pump air into the exhaust system, either into the exhaust
>manifold or into the catalytic converter, to make the converter work efficiently.
At that time, it injected air into the exhaust manifold, very
close to each exhaust valve, so that the exhaust gas would
continue to burn for a while once it left cylinder, reducing exhaust
emissions. There were no catalytic converters at this time to worry
about.
On 1967 AIR equipped cars, the carburetor, air cleaner, and exhaust
manifolds, and other miscellaneous parts were different than on
non-AIR cars, and the factory tune up specs were also different
(different idle speed, etc.). Whether or not the car had AIR was also
noted in the engine block code, which showed the engine assembly plant,
date, cu in, and transmission as well.
---
Rick Inzero, President of the "Put The High Beam Switch Back On The Damn
Floor, Where It Belongs Society"
rochester!cci632!rdi
Northern Telecom LTD uunet!ccicpg!cci632!rdi
Rochester, NY r...@cci.com
-REAL cars have:
vent windows
side air vents down by your feet
the high beam switch on the floor (the way nature intended)
rear-passenger side windows that roll ALL THE WAY down
doors that unlock with the ignition key
doors that lock only when you hold the outside button in
an engine with over 340 lb.-ft. of torque
an engine with a NAME, like "Turbo-Jet" or "Super Commando"
available *optional* power steering; powerful enough to
enable you to parallel park using only 2 fingers
:-) :-) :-)