Running rich - failed emissions

Maybe it had a carb option only for vehicles sold in Canada.

I have a Ford truck, older than your Camaro, with a carb. If it was running too rich, first off I"d want to know under what conditions its running rich? If the problem is only at warm idle I visually check the choke plate is fully opening, and if that wasn’t the problem I’d check for any obvious problems in the vacuum and exhaust systems. If still nothing found I’d adjust the idle mixture screws to lean it out. If it wouldn’t run well then, I’d do a compression test … Well, you see the idea … to solve this requires some further investigation at a shop. If you’re bent on replacing something, replace the carburetor. That might work. But then again it might not, so don’t give up your old carb as part of the swap.

One time my truck was running rich and the cause was a screw that holds the choke plate linkage came loose, and this prevented the choke plate from fully opening.

thank you - those are great options!

I don’t see any options there, those are anecdotal occurrences that may have nothing to do with your vehicle.

You need to focus on your vehicles failure, starting with what mode that the failure occurred in. Was the CO reading high at idle or at speed?

No 1987 Camaro was made in Canada. The choices were Norwood Ohio and Van Nuys California. There was a carbureted engine available in 87 but it was the L69 305 cubic inch V8, not a 350. The 350s were only available with an automatic.

You are dealing with a modified or misidentified car. Until you determine what you have it is tough to help

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Something is just… not right, and as Mustangman theorizes, it is likely either a case of a “modified” vehicle, or an incorrect engine specification in the OP’s posts.

That’s why I asked about the VIN. I expected to see N or L in the 11th digit. If the Cmaro has a carburetor, then the engine was likely replaced. I can’t imagine replacing the throttle body with a carb. It would be too expensive.

This is a pre OBDII so there is no monitoring of the Oxygen sensor and that is the most likely cause. I agree it should not have a carburetor, but if it does, then it would be electronically controlled so it needs the O2 sensor.

Other things, replace plugs and air filter, check the choke linkage and adjustments. The cat could be shot too but that would be the last thing to check/replace, too expensive.

BTW, the TBI (throttle body injection) looks like a carburetor.

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Are you sure it’s not a 305 High Output ?

8th digit of VIN #
Eighth Digit: Identifies the engine.
S = 173 CID, V-6, 2 BC,MFI(Chevy)
F = 305 CID, V-8, MFI(Chevy)
H = 305 CID, V-8, 4 BC (Chevy)
8 = 350 CID, V-8, MFI (Chevy)

I believe the car has the 5.0 L 4 barrel carburetor engine, the 5.7 L engine was only available in the IROC-Z model.

thank you for your comments - im working on it

will do all that - thanks!

thanks for your advice - what I don’t know would fill a book!

Shouldn’t a shop be working on this because you may be running out of time to pass inspection .

And it is not necessary to answer each person because all of the posts are seen by everyone.

Not sure what you mean. My Corolla is pre-OBD II and the computer monitors the O2 sensor to calculate the amount of fuel to inject, and will throw a rich/lean code if it doesn’t like the O2 sensor output.

Just to chime in, I’ve had two instances of too rich fuel mixture. The one was on my FI Riviera. Mileage was somewhere around 16. It had the CRT screen with diagnostics so I could watch the fuel trim as I drove. I replaced the O2 and immediately within 5 miles the thing leaned out to about 27 mpg. The other was a faulty mass air flow sensor. Now if a carb back then, they were leaned way out and then the idle was stepped up to keep them running. You broke the plastic covers on the adjustment jets to get it to run decently, or there is a choke problem not pulling off all the way. But why are they testing an 87? It should be classified as a classic.