CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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Just got back from the sniffer test with my new project car. EPIC FAIL
I failed the 15mph and 25 mph for both HC and CO.
Numbers:
-15 mph: measured 181 HC, Max 133. Measured 1.84 CO, Max .82
-25 mph: measured 150 HC, Max 108. Measured 2.54 CO, Max .62
- Passed NO without a problem
- CO2 readings: 11.6/11.3%, respectively
Failed pretty damn bad for both. Car has a fresh tune up with ACdelco O2, plugs, CTS, PCV, cap rotor.
Car does have a Bad misfire at idle and at speed (somewhat), doing wires tomorrow as that is the only 'tune-up' item I didn't do. Timing is 6BTDC, TPS reading .5, Just set my dwell in at 30 (was pretty far off). The cat looks newer but I have no clue how old it is. The car smells rich. I am new to the CCC qjet (coming from TPI), and learning so ANY input is welcome. Thanks!
Well I know its too much (rich/ rich misfire), I just need to know how to adjust it. Doing wires and double checking for vacuum leaks tomorrow. Also wondering about the float, so I'll probably check that too as well as well leaks.
Car does have a Bad misfire at idle and at speed (somewhat), doing wires tomorrow as that is the only 'tune-up' item I didn't do. Timing is 6BTDC, TPS reading .5, Just set my dwell in at 30 (was pretty far off). The cat looks newer but I have no clue how old it is. The car smells rich. I am new to the CCC qjet (coming from TPI), and learning so ANY input is welcome. Thanks!
Now that you've set the dwell, you have to go back and reset timing. Any time you change dwell, you change timing a corresponding amount. Once you done that, go back and readjust the carb.
Now that you've set the dwell, you have to go back and reset timing. Any time you change dwell, you change timing a corresponding amount. Once you done that, go back and readjust the carb.
True with a points distributor, but since we're talking about the MCS dwell at idle, adjusted via the idle air bleed, it doesn't affect igniton timing.
Just an update, found the bad cylinder, #6. Fixed that, MCS duty cycle ranging between 60-45% in closed loop, spending most of its time in the 55-48% range. Idle smoothed out some but is still slightly rough at times, is this normal for the CCC system?
five7kid,
I still have questions about the carb though, specifically hard starting. I have checked out the choke and it is opating as it should, closed cold, opens gradually. Despite this, the car is hard to start both cold. Once started it fast idles as it should and doesn't die. Its just hard to start in general after sitting about 8 hours. Any ideas on where to start?
The dwell should be 30 degrees on the 6 cyl scale, or 50% duty cycle. You're at least close.
Your float bowl may be emptying while sitting. The most common cause for that is leaking well plugs on the bottom of the main body. They can also cause problems with emissions.
I would change the cat on your car they said that you have to change it every two years. When I did my test I change the cat and had someone adjust the carb alittle and it pass like nothing was wrong with it.
I think for adjustment you have to disconnect the line that goes to the fuel evapor and plug it, then in the mixture needle (don't know the name of the top of my head, but they are the two screw in the bottom side of the carbs) you have to close them clockwise until seated then open them 3 turns counterclockwise. That is how I say the mechanic do it
I hope you pass you test
__________________ Valentin's
1984 Camaro Z28 with a 355/T5
Next motor build involves my 305 again
Adams Time Attack 53.69sec (first timer)
I would change the cat on your car they said that you have to change it every two years. When I did my test I change the cat and had someone adjust the carb alittle and it pass like nothing was wrong with it.
I think for adjustment you have to disconnect the line that goes to the fuel evapor and plug it, then in the mixture needle (don't know the name of the top of my head, but they are the two screw in the bottom side of the carbs) you have to close them clockwise until seated then open them 3 turns counterclockwise. That is how I say the mechanic do it
I hope you pass you test
