Smog Pump Problems

[PHOENIX]

Within the last few weeks my smog pump has been making some noises. First it started off as a rattle sound. I though it was the exhuast or something. I get home and find out its coming from the smog pump. The smog pump pulley has been bent forever and never been a problem. Its not bent bad, but you can see it wobble a little bit. Well now there is a rattle sound coming from it like the pulley is hitting something or loose. But it is not hitting anything and isnt loose at all. I believe the sound is internal. That rattle sound went on and off for a week or two. Now sometimes I hear a humming sound. Similar to something rubbing on a belt. When you hit the gas the sound increase to a point then goes away till the engine speed slows down. I believe this is also coming from the smog pump. Am I missing something, anything else to check?

Anyway have any ways to figure out what is wrong with it?

Should I just get a rebuilt smog pump (Cardone $40-80) and new pulley?

Can I find the new pulley at a gm dealer?

What about a new smog pump from the dealer, cost?

Could the diverter valve be the problem?

If so I know I can get a GP Sorensen diverter valve for $25-30.

How much for a diverter valve from a gm dealer?

Thanks for the help, and yes I have to keep my smog system.

[old Rusty C10]

cant ya just take it out and bypass it i mean thats what i did on my 1986

[PHOENIX]

The pump is shown on the inspection sticker, which is what is used for visual inspection. Without the smog pump and system I will be failed no matter how clean it runs. No choice, must keep the smog system.

[swervin ervin]

First of all, are you sure it was the pulley bent causing the wobble. The bulley bolts directly to the smog pump fan. When it was wobbiing. this makes me think the bearings in the pump were going bad.

Yes, buy a good rebuilt pump. Also, GM sells the pulley and fans, but a rebuilt pump should come with a new fan, maybe not. I've never bought a rebuilt smog pump. Mine is still the same one it came with. I replaced the fan though. Mine got broken by someone, ME.

[PHOENIX]

How does the pump work?
Is there just a fan inside like a turbo?
Or is there a piston type thing in there?
I never really thought about it.

Got any instructions on how to take the pump apart?
I can do it this weekend.
I think it is something inside and now the sound is changing.
I think most likely that fan is bad or going bad and making these noises.

thanks mike

[swervin ervin]

I have no idea what's on the inside. Never had one apart. The fan I'm talking about is the one on the outside where the pulley bolts too. It's sort of like the fan on an alternator. It also is a filter. This is where the intake of the air coming in, comes from. I imagine it has some sort of pump system inside, hence the name smog pump.

I would just replace it and be done with it.

[PHOENIX]

Well I replaced the pump with an A1 Cardone from Checker.
It was $42 ($52 if no core) with life-time warranty. GM dealer wanted $242.00 and didnt even have them in-stock.

Pulley wasnt bent, it was the insides of the pump. Once I got the pulley on the new pump all the way it had almost no wobble at all. Truck runs smoother without all that extra drag and vibration. This damn pump was making more noise then I knew. Truck makes less noise now. Its great

When I had both pumps in hand the bad pump would spin very easy and makes some nasty noise then get wedged every once in awhile. The new pump didnt spin easy and you could feel it was working when spun in hand. I felt the air coming out at the manifolds (have a loose tube) and the new pump is easily pumping 3-times the air the old one was.

I kept my old pump instead of returning it for the $10 core.
I am going to open it up and look inside, I have to know whats in there . If I can put it back together then Ill return it for the $10 core.

[swervin ervin]

Sounds great. Glad you got it figured out.

Now you will get lower emission readings. I think this should help all around in the emissions department. It will probably help the cat last longer too.

Squeeks, rattles, vibrations, and grinding are things that drive me totally nuts.

[Eyegore]

Glad to here you got your pump on, I know I had to put one on a 75 truck that was converted over from a diesel engine, try doing that w/o all the brackets for the 1st time. Now I've got a question, why does your 83 have a smog pump and my sons 82 does not? Is the difference a 305 / 350, 035 less polluting?
And did you pull the pump apart to see what was inside?

[PHOENIX]

Are you sure your '82 doesnt have to have a pump on it?
I havent pulled it apart yet, but maybe tonight. Ill take pictures.
I have a little video showing the bad one and the good one being spun by hand, should help someone later determine if theres is junk or not.

[PHOENIX]

Ok guys I tried to take this damn thing apart.
But couldnt get it as far as I would have liked too.

First Picture shows where the air enters the pump from the pulley side. This picture shows the pulley and fan/filter off:

[PHOENIX]

This picture shows the back cover off.

[PHOENIX]

This picture shows the inside of the back cover. Notice how the shaft is not centered. Bearings for the internal fan blades ride on this shaft.

[PHOENIX]

This picture shows a lot. The air comes in from the lower right opening, then is pushed around by the two fan blades (one fan blade can be seen on the left). The big opening at the bottom is where the air exits and goes to the diverter valve. The shaft from the back cover goes down into the middle. The blades ride on the walls of the housing and go in and out as needed,notice offset of tube which matches back cover. Not sure why that is, maybe more air can be pumped this way.

[PHOENIX]

I couldnt get the front apart to get this cylinder and fan blades out. So this is the best picture I could get. Without the shaft going through the bearings the fans just float inside the cylinder. You can see at the bottom of the cylinder a slot where one of the blades would come out. This slot is lined with metal pieces that are all busted apart on mine. The entire cyliner spins with the pulley, the slot on the side drags the blade around. The blades attach to the bearing with little pieces of plastic or nylon. The blades are like a metal, I am not sure what they are. Doesnt look like it would be something you could service at home. Much easier to buy a rebuilt. Kind of interesting, not really what I expected to see inside. Now I understand why is sounded like sh*t

[Eyegore]

So basically it pumps more air into the system. Yes I'm sure that there is no pump on my sons, that was the first thing I looked for when having to put everything back on. When I originally bought the truck from my neighbor it had just gone through emissions, then the engine blew and trans went out, replaced both. Well two years went by and back to emissions, it failed, missing components. So I checked out the schematic on the front, added an egr valve, it was not there when I bought it-wonder how the emission guys missed that when t passed previously, then all vacuum lines, added a new cooling neck with vacuum (temp sensing I believe). Still would not pass, finally had to take it to a mechanic to have the carb rejetted. And they went through emissions to get it to pass.
To bad I don't lve out in the rurals where you don't have to go through the emission hassel.