What all is wrong with my 305 carbureted emissions system?
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What all is wrong with my 305 carbureted emissions system?
I just got this '84 Camaro Z28 and it has problems all over with the emissions system. I'd like to get it to mostly stock configuration, but everything is so different than it's supposed to be that I'm overwhelmed. Anything stick out to you guys? Any tips?
Edit: the charcoal canister is completely bypassed, but I don't know enough to say anything about the rest of it
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From: CT
Car: 82 TA
Engine: Zz430 clone w a torquestorm blower
Transmission: Magnum f
Axle/Gears: Ford 9 w 4.11
Re: What all is wrong with my 305 carbureted emissions system?
Your air injection is gone. The headers on it don't have provisions for it. There's a ton of vacuum lines/switches/valves missing as well as other parts. Does the car run well? It's gonna be a bit of work getting all the parts, installing them and getting it all working well. What's your goal?
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Re: What all is wrong with my 305 carbureted emissions system?
Your air injection is gone. The headers on it don't have provisions for it. There's a ton of vacuum lines/switches/valves missing as well as other parts. Does the car run well? It's gonna be a bit of work getting all the parts, installing them and getting it all working well. What's your goal?
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Re: What all is wrong with my 305 carbureted emissions system?
Since it's an '84, and hopefully still has the ECM and its wiring harness, it can be made to run fairly well.
1. Ditch the shiny Hot Air Intake and try to find a stock-ish air cleaner with a snorkel. That will permit actual cool air to feed the carb once the engine is warmed to temperature.
2. Reconnect an intake air temperature sensor to that loose connector hanging there. If you're lucky and find a stock air cleaner, it will likely have an IAT sensor.
3. With an '84, you should be able to "fool" the ECM by installing a 180Ω or similar resistor in the place of the Air Injection port and divert solenoids, preventing setting any nuisance codes. If it has a relatively modern 3-way converter, the added air is useless anyway.
4. Verify the carb has the MC solenoid operating and adjusted correctly.
5. There appears to be a MAP and BARO sensor still installed, so make sure thy are functioning.
6. Verify the TPS setting and function, since it appears to still be wired.
7. Verify it has a functioning oxygen sensor reporting to the ECM.
Doing all the above can potentially keep it in normal closed-loop mode. This will enable fuel mixture control and a functioning EST. You can toy with the float, secondary metering, and base timing to have some fun, and still have decent street manners and respectable fuel mileage.
1. Ditch the shiny Hot Air Intake and try to find a stock-ish air cleaner with a snorkel. That will permit actual cool air to feed the carb once the engine is warmed to temperature.
2. Reconnect an intake air temperature sensor to that loose connector hanging there. If you're lucky and find a stock air cleaner, it will likely have an IAT sensor.
3. With an '84, you should be able to "fool" the ECM by installing a 180Ω or similar resistor in the place of the Air Injection port and divert solenoids, preventing setting any nuisance codes. If it has a relatively modern 3-way converter, the added air is useless anyway.
4. Verify the carb has the MC solenoid operating and adjusted correctly.
5. There appears to be a MAP and BARO sensor still installed, so make sure thy are functioning.
6. Verify the TPS setting and function, since it appears to still be wired.
7. Verify it has a functioning oxygen sensor reporting to the ECM.
Doing all the above can potentially keep it in normal closed-loop mode. This will enable fuel mixture control and a functioning EST. You can toy with the float, secondary metering, and base timing to have some fun, and still have decent street manners and respectable fuel mileage.
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Junior Member
Joined: Oct 2025
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Re: What all is wrong with my 305 carbureted emissions system?
Since it's an '84, and hopefully still has the ECM and its wiring harness, it can be made to run fairly well.
1. Ditch the shiny Hot Air Intake and try to find a stock-ish air cleaner with a snorkel. That will permit actual cool air to feed the carb once the engine is warmed to temperature.
2. Reconnect an intake air temperature sensor to that loose connector hanging there. If you're lucky and find a stock air cleaner, it will likely have an IAT sensor.
3. With an '84, you should be able to "fool" the ECM by installing a 180Ω or similar resistor in the place of the Air Injection port and divert solenoids, preventing setting any nuisance codes. If it has a relatively modern 3-way converter, the added air is useless anyway.
4. Verify the carb has the MC solenoid operating and adjusted correctly.
5. There appears to be a MAP and BARO sensor still installed, so make sure thy are functioning.
6. Verify the TPS setting and function, since it appears to still be wired.
7. Verify it has a functioning oxygen sensor reporting to the ECM.
Doing all the above can potentially keep it in normal closed-loop mode. This will enable fuel mixture control and a functioning EST. You can toy with the float, secondary metering, and base timing to have some fun, and still have decent street manners and respectable fuel mileage.
1. Ditch the shiny Hot Air Intake and try to find a stock-ish air cleaner with a snorkel. That will permit actual cool air to feed the carb once the engine is warmed to temperature.
2. Reconnect an intake air temperature sensor to that loose connector hanging there. If you're lucky and find a stock air cleaner, it will likely have an IAT sensor.
3. With an '84, you should be able to "fool" the ECM by installing a 180Ω or similar resistor in the place of the Air Injection port and divert solenoids, preventing setting any nuisance codes. If it has a relatively modern 3-way converter, the added air is useless anyway.
4. Verify the carb has the MC solenoid operating and adjusted correctly.
5. There appears to be a MAP and BARO sensor still installed, so make sure thy are functioning.
6. Verify the TPS setting and function, since it appears to still be wired.
7. Verify it has a functioning oxygen sensor reporting to the ECM.
Doing all the above can potentially keep it in normal closed-loop mode. This will enable fuel mixture control and a functioning EST. You can toy with the float, secondary metering, and base timing to have some fun, and still have decent street manners and respectable fuel mileage.
Last edited by Chronomize; Oct 23, 2025 at 09:39 PM.
Joined: Jul 2000
Posts: 6,521
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From: Aridzona
Car: `86 SS / `87 SS
Engine: L69 w/ TPI on top / 305 4bbl
Transmission: `95 T56 \ `88 200-4R
Re: What all is wrong with my 305 carbureted emissions system?
The ECM Q-jet setup can return 25mpg. Familiarize yourself with it and how to adjust primaries by the book. The secondaries are purely mechanical.
Thread Starter
Junior Member
Joined: Oct 2025
Posts: 4
Likes: 0
Re: What all is wrong with my 305 carbureted emissions system?
Since it's an '84, and hopefully still has the ECM and its wiring harness, it can be made to run fairly well.
1. Ditch the shiny Hot Air Intake and try to find a stock-ish air cleaner with a snorkel. That will permit actual cool air to feed the carb once the engine is warmed to temperature.
2. Reconnect an intake air temperature sensor to that loose connector hanging there. If you're lucky and find a stock air cleaner, it will likely have an IAT sensor.
3. With an '84, you should be able to "fool" the ECM by installing a 180Ω or similar resistor in the place of the Air Injection port and divert solenoids, preventing setting any nuisance codes. If it has a relatively modern 3-way converter, the added air is useless anyway.
4. Verify the carb has the MC solenoid operating and adjusted correctly.
5. There appears to be a MAP and BARO sensor still installed, so make sure thy are functioning.
6. Verify the TPS setting and function, since it appears to still be wired.
7. Verify it has a functioning oxygen sensor reporting to the ECM.
Doing all the above can potentially keep it in normal closed-loop mode. This will enable fuel mixture control and a functioning EST. You can toy with the float, secondary metering, and base timing to have some fun, and still have decent street manners and respectable fuel mileage.
1. Ditch the shiny Hot Air Intake and try to find a stock-ish air cleaner with a snorkel. That will permit actual cool air to feed the carb once the engine is warmed to temperature.
2. Reconnect an intake air temperature sensor to that loose connector hanging there. If you're lucky and find a stock air cleaner, it will likely have an IAT sensor.
3. With an '84, you should be able to "fool" the ECM by installing a 180Ω or similar resistor in the place of the Air Injection port and divert solenoids, preventing setting any nuisance codes. If it has a relatively modern 3-way converter, the added air is useless anyway.
4. Verify the carb has the MC solenoid operating and adjusted correctly.
5. There appears to be a MAP and BARO sensor still installed, so make sure thy are functioning.
6. Verify the TPS setting and function, since it appears to still be wired.
7. Verify it has a functioning oxygen sensor reporting to the ECM.
Doing all the above can potentially keep it in normal closed-loop mode. This will enable fuel mixture control and a functioning EST. You can toy with the float, secondary metering, and base timing to have some fun, and still have decent street manners and respectable fuel mileage.
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