My 1984 Silverado failed NC inspection today for missing an O2 sensor.

[jrblanke]

I am trying to get my Silverado back on the road. Before purchasing it last month, it had been not been inspected in NC for the previous 5 years (sitting unregistered).

Today it failed inspection for a few minor things (missing gas cap, exhaust leak, etc). One of the items that was on the list was that it was missing the oxygen sensor. My truck is carbureted now just as it was when it was new. The only difference from stock is that it has a goodwrench 5.7L instead of the factory 5.0L. It has a catalytic converter and all smog equipment.

Should I just tell the inspection place that my truck never had an oxygen sensor? Maybe it did? I thought O2 sensors were only for fuel injected cars (therefore starting in 1987 for Chevy trucks).

Please correct me if I am wrong. Thanks,


James

[Dieselholic92]

It shouldn't have had O2 sensors since it's carburetor

[snm95ls]

Originally Posted by Dieselholic92

It shouldn't have had O2 sensors since it's carburetor

Agreed. I don't think the CCC (computer controlled carb) crap ever made it to the trucks.

[AntiGov]

not sure on the sensor.....but only 4% of vehicles dont pass...thats 96% that do pass, 96% is almost 100%.......our government wastes billions of our dollars on 4%....4% has no effect on any thing ! maybee buy an old exempt square and switch plates....

[86454k30]

Trucks did not have O2 sensors until 87 when they got fuel injection. I would tell the test station it never had one. I would hope if they are passing/failing on visual inspections they would/should know what they are looking at/for.

And 1/2 ton trucks, suburban and K5 did have computer controlled carburetors from 81ish to 86.

[snm95ls]

Originally Posted by 86454k30

Trucks did not have O2 sensors until 87 when they got fuel injection. I would tell the test station it never had one. I would hope if they are passing/failing on visual inspections they would/should know what they are looking at/for.

And 1/2 ton trucks, suburban and K5 did have computer controlled carburetors from 81ish to 86.

I just saw a pic of one in another thread.

Decided to look it up on Alldata, and in 84 it does show an oxygen sensor for the 350-L engine as well as the 305-H engine.

Heh, learn something new I guess unless the diagrams are wrong.

[jhngardner367]

Look at the emissions sticker.If it says CCC system,it came with an 02 sensor,and it will have a knock sensor in the side of the block,and an ECS(electronic spark control)module on the firewall or engine,near the heater housing. USUALLY,if it had an A.I.R. system,and a heat-riser,it WON'T have an o2 sensor.NOTE: If there's an ALDL(Assembly Line Data Link)under the dash,it came with an o2 sensor.

[Littletony]

Your truck should only need a safety inspection. Any thing older then 15 years does not need a emission inspection in the state of NC. But the truck will still have to retain all factory emission equipment that was installed. Fix the missing gas cap and exhaust leak. Then I would find another inspection station.
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[jrblanke]

Thanks for the replies everyone.

I'll check the emissions sticker when I get home this morning. My truck has the high altitude emissions package (not sure if that means anything). Not sure what A.I.R system is, but I do believe it has a heat riser. As far as the 305-H engine goes, I believe there is a 305-F too? I am not sure of the difference.

Where would the O2 Sensor be mounted? It's in the exhaust pipe right below the manifold, is that correct? If there was one I should be able to find a plug or wire hanging somewhere.

Again, thanks for the help.

James

[andrewmp6]

If it has one it should be in the exhaust looks like a spark plug with wires on it close to engine.A carb engine can have o2s i had a 84 f150 that was carbed that had a o2 on it as funny as it sounds it can be true tho.

[Number21]

Sounds like you need a 73/74 cab.

[jrblanke]

Here are some pictures I took today. Like everyone says, I think my truck did have an O2 sensor originally.

Does anyone know where it was originially located (drivers side or passenger side exhaust pipe) so I can find where the original wire is on the engine harness. According to a wiring diagram I have, I am looking for a purple wire. I think the ground wire is a tan color.







Passenger side











Driver side

[silvereagle07]

I can't read the emissions label. You said it was a High alt. emmissions label right. What does it say beside the Ign. timing degree BTDC @rpm? 4@600? The only 5.0 or 5.7 that had an o2 sensor was California emmisions vehicles. That label would say ign. timing 8@500 btdc and you would also have a MIL light on the dash. Oh btw I am reading that straight from the NCDMV testing manual and I am a NC liscensed inspector. I think they may have misread the label. Hope this helps.

['79squared]

You could always move to washington state where the inspection stops when your rig turns 25. IN THE CLEAR

[jrblanke]

Originally Posted by silvereagle07

I can't read the emissions label. You said it was a High alt. emmissions label right. What does it say beside the Ign. timing degree BTDC @rpm? 4@600? The only 5.0 or 5.7 that had an o2 sensor was California emmisions vehicles. That label would say ign. timing 8@500 btdc and you would also have a MIL light on the dash. Oh btw I am reading that straight from the NCDMV testing manual and I am a NC liscensed inspector. I think they may have misread the label. Hope this helps.

Wow, and NC inspector on the forum! Thank you very much for your response!

I have uploaded another picture of the sticker so you can see. The timing degree at BTDC is 4@600. I will be putting on a new exhaust system this weekend, and I have several other parts on order. Like you said, ill just explain to them that the truck was never equipt with an O2 sensor.

So the fact that the truck has a replacement engine (was 5.0, replacement is 5.7) should not matter correct?

[beamn7]

CA emission'd feedback carbs had one 02 sensor in one manifold (essentially measuring only one side of the engine). My 85 was originally a 305F (350 now) truck and has the o2 in the pass. side manifold, feedback / ecm carb (2 stage accelerator pump,TPS and Mixture control solenoid), A.I.R., E.F.E, distributor with NO vaccum advance or centrifigul (solely controlled by ecm) and NO E.S.C. module or knock sensor (which I always found strange but hey, it's CA).... So yes, Carbureted engines did exist with 02 sensors but mostly out here in the land of fruits and nuts (I can say that, I'm from Boston originally LOL). Yours most likely is not equipped with one and I agree with the others, take it to another shop....
Had a smog shop tell one of our vehicle owners (I'm a OEM field service rep) the other day that his 22,000lb GVW vehicle is supposed to have 4 o2 sensors. Sorry, wrong answer, heavy duty emissions does not require post catalyst o2's. Had to call the shop and explain as did the Bureau of Automotive Repair....

Not uncommon for a shop to make a mistake and fail a vehicle for a reason that it should not have been failed....

[silvereagle07]

Originally Posted by jrblanke

Wow, and NC inspector on the forum! Thank you very much for your response!

I have uploaded another picture of the sticker so you can see. The timing degree at BTDC is 4@600. I will be putting on a new exhaust system this weekend, and I have several other parts on order. Like you said, ill just explain to them that the truck was never equipt with an O2 sensor.

So the fact that the truck has a replacement engine (was 5.0, replacement is 5.7) should not matter correct?

I was looking at the 2010 MOTOR Emissions Control Applications Manual that I had in my bay. They are generally all the same. By your Emmissions sticker you have a High altitude Vehicle as indicated by a circled 7 and 9 at the engine size in the manual. Page 64-13. The fact that you swapped engines does not matter as long as you have all the original emissions equipment installed. You truck requires a thermostatic air cleaner, pcv system, air injection pump, egr system , evap canister, cat, spk control and fuel fillpipe restrictor. Good luck, glad I could help.

[gchemist]

My factory manual has wiring for O2 sensors as far as '83. Cali models had them. Not sure about others.

[jhngardner367]

My '85 is a factory-stock 5.0,other than the carb being changed,and it didn't come with an02,or even a cat.I just got the parts to swap it to a dual exhaust,and I don't even worry about air-pumps,and egr valves.

[Stepper86]

My 86 has the Co2 sensor, it´s located in the driver side manifold, pointing straight towards the cab. Here is a picture of the mainfold, red arrow shows were it sits. My truck is Californis emissons equiped and all stock, except for dual exhaust pipes.