Need emissions help

[76er]

Hello, have 1990 Silverado 1/2 ton, 2 wheei drive, 350 engine, extended cab.
Smog pump missing off this truck and won't pass inspection in my state, only requires safety inspection but if it came with pump has to have it on there. Willing to buy one but don't know if im missing what ever the pump connects to
so i've been searching everywhere for a diagram of the emmissions system for my truck with no luck, have found a couple that supposedly are for my truck but it shows it with the air injection pipes that screw into the heads like the 80s model trucks and these models didn't have those, even my Chilton manual doesn't show mine. Does anyone have a diagram or know what the pump attaches to? 1988 to 1993 are the same, 1994 and newer are different. Thanks for any help.

[ChevyTech]

This is from a 1993 fuel & emissions manual.

[ChevyTech]

I edited my post to only have one photo at a time because with some browsers this site messes up multiple photo posts.
These are from the 1993 Fuel & Emissions Manual.

[ChevyTech]

Another from the 1993 manual.

[Mr_Rich]

I don't understand this requirement. I have a Calif. truck and it never had an AIR pump. Calif. was typically the state that required equipment like AIR so I don't know why NC would need it. Do you have exhaust manifolds where someone put plugs in pipe holes or are they bare of those ports.

[95 S_Trucker]

Originally Posted by Mr_Rich

I don't understand this requirement. I have a Calif. truck and it never had an AIR pump. Calif. was typically the state that required equipment like AIR so I don't know why NC would need it. Do you have exhaust manifolds where someone put plugs in pipe holes or are they bare of those ports.

PA has similar emissions laws. For 1975-1995 model year vehicles under 9,000 gvw, all vehicles must have the same emissions equipment it came from the factory with.

[mountie]

If 76r could post a picture, showing the lower passenger area... Then we can see what is missing - needed. ( Is the smog mount bracket there?)

[Mr_Rich]

This raises a question in my mind; is there a code in the option list that indicates the requirement for an AIR pump and related hardware?

[mountie]

Originally Posted by Mr_Rich

This raises a question in my mind; is there a code in the option list that indicates the requirement for an AIR pump and related hardware?

The dealer should know by the VIN number? If the emissions decal on the fan shroud is missing...... that decal will show it clearly.

[Mr_Rich]

As a matter of fact I still have the original upper fan shroud off my truck. When my truck was still relatively new the 305 had a factory defect/ cracked engine block in the lifter valley. I checked the oil one day and there was chocolate jello under the oil filler cap. This was at 30K miles. So I take my truck to the dealer for warranty work and the dealer "mechanic" (I hesitate to use the term) said that they only authorized replacement of the short block and so they put the damaged heads on the new short block. This guy cross threaded some SAE bolts into metric threaded holes and other assorted nightmares along with breaking the upper fan shroud. I gave up with dealership mechanics at that point. I had problems with the work that was done and months later I went to the local Pontiac dealer and bought a 350 OTC and installed it into my truck at the curb outside my apt. at the time. Best thing I could do at the time. I know I got side-tracked here but ignore it if you will and refer to the pics I posted.

[mountie]

Mr Rich...

If your crappy engine repair was at a GM dealership, then you have a warranty ( if your original warranty / extended warranty is in effect)....
If you return to any GM dealer due to their (GM) bad repairs, & they accept the truck - ( same complaint / second visit),..... Automatically, that repair is exempt from any time/ mileage limitations.

[speedygonzales]

Originally Posted by 95 S_Trucker

I know this is a couple of months old, but that pic of your emissions label shows that your truck came from the factory without the air pump. It's not required to pass emissions.

Pretty sure he knows that

Originally Posted by Mr_Rich

I don't understand this requirement. I have a Calif. truck and it never had an AIR pump.

Originally Posted by mountie

Mr Rich...

If your crappy engine repair was at a GM dealership, then you have a warranty ( if your original warranty / extended warranty is in effect)....
If you return to any GM dealer due to their (GM) bad repairs, & they accept the truck - ( same complaint / second visit),..... Automatically, that repair is exempt from any time/ mileage limitations.

No it does NOT. What makes you think that? Warranty repairs are only in effect as long as the original warranty period. Lets say you get warranty repair that is on 6 years/ 50000 miles. Your vehicle is at 4 years / 48000 miles at the time of the repair. After 50000 miles or 6 years, which ever comes first. There is no more warranty.

It's also pretty obvious that he didn't care to answer back in April so chances are good he's done with this thread.

[95 S_Trucker]

Originally Posted by Mr_Rich

As a matter of fact I still have the original upper fan shroud off my truck. When my truck was still relatively new the 305 had a factory defect/ cracked engine block in the lifter valley. I checked the oil one day and there was chocolate jello under the oil filler cap. This was at 30K miles. So I take my truck to the dealer for warranty work and the dealer "mechanic" (I hesitate to use the term) said that they only authorized replacement of the short block and so they put the damaged heads on the new short block. This guy cross threaded some SAE bolts into metric threaded holes and other assorted nightmares along with breaking the upper fan shroud. I gave up with dealership mechanics at that point. I had problems with the work that was done and months later I went to the local Pontiac dealer and bought a 350 OTC and installed it into my truck at the curb outside my apt. at the time. Best thing I could do at the time. I know I got side-tracked here but ignore it if you will and refer to the pics I posted.

I know this is a couple of months old, but that pic of your emissions label shows that your truck came from the factory without the air pump. It's not required to pass emissions.

[Mr_Rich]

We probably lost the OP with all of our back-and-forth comments. And I still don't trust dealerships unless I work there and I'm not hired at any and so it goes. My old truck has almost 289K miles with just me as the mechanic for the last twenty-five or so years. I've replaced/ repaired everything in the drivetrain during that time. It doesn't look pretty but I still like that old truck; gray primer and all. The interior is in clean and very good condition. Amazing what a upholstery cleaning machine can do to freshen things up.