Remove or replace AIR valve & pump?
Thread Starter
Pro
Joined: Jun 2001
Posts: 509
Likes: 5
From: Edmonds WA
Remove or replace AIR valve & pump?
I ran flat out of time to diagnose the recent emissions failure (barely high on HC (280) at idle) on my 87, so I took it to the local shop. They report that the AIR management valve is stuck--shut. Therefore, the cats aren't lighting up properly at cold idle.
I remember reading about people removing the AIR pump altogether... any lessons learned doing that? Apparently the valve is about $200 new.
BTW, I'm planning to replace most of the exhaust system next week (since the rear Y-pipe has 3 holes in it!). I'm having a stock LT-1 system put in behind two mini-cats, so apparently I won't have need for the air injection to the cat anymore.
Any experience to share?
Thanks much!
I remember reading about people removing the AIR pump altogether... any lessons learned doing that? Apparently the valve is about $200 new.
BTW, I'm planning to replace most of the exhaust system next week (since the rear Y-pipe has 3 holes in it!). I'm having a stock LT-1 system put in behind two mini-cats, so apparently I won't have need for the air injection to the cat anymore.
Any experience to share?
Thanks much!
Burning Brakes
Joined: May 2004
Posts: 1,230
Likes: 27
From: Athens Ohio
You are right. You won't need that AIR diverter pump. I have an 86 and replace my exhaust system with a LT4 exhaust. I attached it right behind the precats, just as you have planed. If you don't remove that air diverter and air tube to the old cat, you are going to hear a lot of noise.
I just replace that pump about 2 years ago. They are expensive. If you don't do your changes and need one let me know.
I just replace that pump about 2 years ago. They are expensive. If you don't do your changes and need one let me know.
Team Owner
Joined: Jun 2001
Posts: 26,196
Likes: 0
From: Orlando FL
St. Jude Donor '08-'09
If your area doesn't have inspections where this useless part is required, then remove it. The elim kit is about the same price as a new pump anyway.
If your area requires one for the visual inspection, then "mod" it for free. Open the pump up, yank out all the internals, grease up the pulley on it and reinstall. it will be a free spinning pulley attached to the pump shell. Nobody will know the difference on visual inspection.
I removed mine many years back when mine froze up on me and havn't looked back.
If your area requires one for the visual inspection, then "mod" it for free. Open the pump up, yank out all the internals, grease up the pulley on it and reinstall. it will be a free spinning pulley attached to the pump shell. Nobody will know the difference on visual inspection.
I removed mine many years back when mine froze up on me and havn't looked back.
Thread Starter
Pro
Joined: Jun 2001
Posts: 509
Likes: 5
From: Edmonds WA
Is the pump and air management valve all one assembly?
When I picked the car up this morning, the mechanic pointed out that there are two pieces to the system--he said later that year, GM went to a one-piece setup.
I'm happy to get rid of something I don't need anymore, of course. And they don't seem to do visual inspections, unless you fail and require a 'waiver' (which will likely be the case for me this time, because I've spent the requisite $150+ at a shop and the problem is still not fixed). However, I'm led to believe that I'll pass in the future with the new exhaust system, including the new cats (BTW, just to clarify, the new system will attach new mini cats right behind the stock exhaust manifold).
When I picked the car up this morning, the mechanic pointed out that there are two pieces to the system--he said later that year, GM went to a one-piece setup.
I'm happy to get rid of something I don't need anymore, of course. And they don't seem to do visual inspections, unless you fail and require a 'waiver' (which will likely be the case for me this time, because I've spent the requisite $150+ at a shop and the problem is still not fixed). However, I'm led to believe that I'll pass in the future with the new exhaust system, including the new cats (BTW, just to clarify, the new system will attach new mini cats right behind the stock exhaust manifold).
Race Director
Joined: Jun 2004
Posts: 13,961
Likes: 707
From: WI
On my year there are a few parts to the AIR system. The pump itself which you can gut or install an expensive replacement pulley. Sometimes you can find those used for a reasonable price. There are also hoses and some connectors, all of which you can remove. You must cap the fittings at the exhaust manifolds though. I used a short part of hose and sawed a bolt that fit tight into the hose, then put epoxy on the bolt. The caps held with tie wraps for clamps for years till I got headers.
I do not think this is your trouble with emissions though. If you drive the car to get tested it will be warmed up. The air system should really only be helping when the car is cold.
I do not think this is your trouble with emissions though. If you drive the car to get tested it will be warmed up. The air system should really only be helping when the car is cold.
Intermediate
Joined: Dec 2006
Posts: 33
Likes: 0
From: Ojai CA
Me, too...
My pump or valve has a problem, I'm tearing into it this week-end to see WTF. It's making noise, and the pulley does make a slight noise of its own when you remove the belt and spin it by hand. But the noise under operation is more of a whine - sounds like air. I'm thinking bad connection or bad valve.
And of course, I'm in the People's Republic of California, so I can't just gut or remove the darn thing...
Mike from Ojai
'87 Coupe
And of course, I'm in the People's Republic of California, so I can't just gut or remove the darn thing...
Mike from Ojai
'87 Coupe
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Until the LT1's, the Air Pump is/was used to light off the O2/CAT and after Closed Loop, clean up what the CAT can't handle. Go without it on startup and you can stay in Open Loop and if you think that's efficient or creates extra horsepower - ok that's you're opinion. Anyway, there are two parts: the Pump itself and then the solenoid valves which switch air from the Headers to the CAT or just overboard to prevent backfiring under Decel. Rebuilt Pumps are 40 to 60 Bucks the Solenoids $200 or so. Most of the time, the Solenoids don't switch or work because of a wiring problem. Troubleshooting is quite simple. See if there's a ground on completed circuit on the one that's suppose to be firing at the ECM. If so, and the air isn't blowing out of the right hose, the solenoid is bad. On the other hand, if a test light to voltage lights up at the ECM, there's an open in the wire somewhere between the ECM and the solenoid.
Race Director
Joined: Jun 2004
Posts: 13,961
Likes: 707
From: WI
Until the LT1's, the Air Pump is/was used to light off the O2/CAT and after Closed Loop, clean up what the CAT can't handle. Go without it on startup and you can stay in Open Loop and if you think that's efficient or creates extra horsepower - ok that's you're opinion. Anyway, there are two parts: the Pump itself and then the solenoid valves which switch air from the Headers to the CAT or just overboard to prevent backfiring under Decel. Rebuilt Pumps are 40 to 60 Bucks the Solenoids $200 or so. Most of the time, the Solenoids don't switch or work because of a wiring problem. Troubleshooting is quite simple. See if there's a ground on completed circuit on the one that's suppose to be firing at the ECM. If so, and the air isn't blowing out of the right hose, the solenoid is bad. On the other hand, if a test light to voltage lights up at the ECM, there's an open in the wire somewhere between the ECM and the solenoid.
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Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If it's an LT1, it has a heated sensor along with an electric pump that shuts off fairly quickly. Most cars eventually get to Closed Loop, even if not heated. From an emissions standpoint, the quicker the better and to a lesser extent, the more efficient in terms of fuel usage. Anyone who can make something reliable and fuel efficient while ditching some of this stuff - short of going all electric - stands to make a lot of Bucks.
Thread Starter
Pro
Joined: Jun 2001
Posts: 509
Likes: 5
From: Edmonds WA
So, I could fix/replace the solenoid, but if I'm replacing all 3 of the stock cats with 2 new mini cats, I wouldn't need to connect up the AIR tube to the cats anyway... right? If it's not feeding air to the cat, is it going to do any good at all?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Depends on the efficiency of the CATS. Newer designs don't need it and current offerings use an electric motor to heat up the O2(s) faster. Question is what do you do with the air? Pumping it overboard creates or can create an obnoxious noise. Some delete it altogether and then go with a heated O2. To me, seems like a lot of work and you may end up with less perfomance; mainly gas mileage, with no appreciable increase in anything else.
Burning Brakes
Joined: May 2006
Posts: 857
Likes: 1
From: Morrisonville Illinios
When we removed the exhaust on our 87' and went with long tube MELROSE hdrs we made up our own air pump eliminator. Took about an hour of time and about $30 bucks of parts. Hell we even set it up so we could use the original belt.
wro87
wro87
Instructor
Joined: Nov 2006
Posts: 207
Likes: 0
From: Duluth Georgia
I have an 86 with the same exhaust from factory, except for the rear y-pipe and mufflers...they were replaced about 2 years ago by the previous owner. Anyway, after I bought the car I was oging over the entire car and notice that the air pipe that goes to the cat was cut about half way down and crimped shut. Then the pipe connecting to the cat was removed.
When I took the car to have emissions done it failed the first time due to running too rich. I checked over everything and found that the fuel injectors were leaky and replaced them. Then I took it in again and passed. Yep, that was a pass without the airtube connected to the 20 year old cats.
When I took the car to have emissions done it failed the first time due to running too rich. I checked over everything and found that the fuel injectors were leaky and replaced them. Then I took it in again and passed. Yep, that was a pass without the airtube connected to the 20 year old cats.
