Carb misadjusted?

[mike561]

got an 83 caprice, 4bbl carb 305 motor, recently ive noticed when im at a complete stop and i go to stomp on the gas the car seems like it dies for a second, and, to better explain, if i stop completely then rapidly stomp on the gas pedal a few times the engine will actually stall. it only does this in drive not park. other then that it doesnt seem to be lacking power, doesnt sound like its pinging or misfiring either (i just changed the plugs and wires about 2 weeks ago) is this a carb adjustment? i recall someone saying it could be a failing fuel pump also...

[Blt2Lst]

Originally Posted by mike561

got an 83 caprice, 4bbl carb 305 motor, recently ive noticed when im at a complete stop and i go to stomp on the gas the car seems like it dies for a second, and, to better explain, if i stop completely then rapidly stomp on the gas pedal a few times the engine will actually stall. it only does this in drive not park. other then that it doesnt seem to be lacking power, doesnt sound like its pinging or misfiring either (i just changed the plugs and wires about 2 weeks ago) is this a carb adjustment? i recall someone saying it could be a failing fuel pump also...

It does sound like a carb issue, have you checked the fuel pressure?
When was the last time it was rebuilt?

I just had mine rebuilt (stage 1) by these guys, the car runs much better now..
http://smicarburetor.com/products/sf...D2/86/sfID3/34

[mike561]

Havent checked the fuel pressure, but yeah im thinking im going to just have it rebuilt, i have no idea when the last time it was (or if it was ever) rebuilt. How does that site work in the link? do you send them your carb to be rebuilt or do they send you one? also about how much am i looking at for a carb rebuild at a shop?

[j cAT]

Originally Posted by mike561

Havent checked the fuel pressure, but yeah im thinking im going to just have it rebuilt, i have no idea when the last time it was (or if it was ever) rebuilt. How does that site work in the link? do you send them your carb to be rebuilt or do they send you one? also about how much am i looking at for a carb rebuild at a shop?

you check for vacuum leaks first...this is the biggest problem with these old carb engines....everyone jumps on the carb....

using a vacuum guage you test every line and vacuum operated device for leaks,....

[Blt2Lst]

Originally Posted by j cAT

using a vacuum guage you test every line and vacuum operated device for leaks,....

Good point, lots of vacuum tubing and lots of potential leaks.
Now might be a good time to replace all the vac line, cheap insurance.

[Blt2Lst]

Originally Posted by mike561

Havent checked the fuel pressure, but yeah im thinking im going to just have it rebuilt, i have no idea when the last time it was (or if it was ever) rebuilt. How does that site work in the link? do you send them your carb to be rebuilt or do they send you one? also about how much am i looking at for a carb rebuild at a shop?

You send them your carb and they rebuild it. Cost was $225 plus mine needed a TPS sensor so total was $250. Thats for the stage 1 rebuild.
You read about this shop in the mags and they even mention on hp tv.

[NOVAZ27]

Check the following before spending the bucks for a rebuild.
1. The afore mentioned vacuum leaks.
2. Accelerator pump. Shot volume.
3. Oxygen sensor. This tells the computer that tells the CC Quadrajet what fuel mixture to use. Change out at 50-60k miles.
4. ACDelco 213-4547: ENGINE COOLANT TEMPERATURE SENSOR located in themostat housing. Helps the computer determine mixture ratio. Loose wire here can cause problems.
5. Choke opening up early, Electric element gets weak after time.
6. Is the mixture solenoid working / adjusted properly.

My bet is on the accellerator pump.
The reason I am suggesting these items is I just went thru the same issues with my 1984 CC Quadrajet. The carb has 322k mi. on it. As did the oxygen sensor, temp sensor etc. Accel pump, oxygen sensor made a world of difference.

HOPE THIS HELPS

[j cAT]

Originally Posted by NOVAZ27

Check the following before spending the bucks for a rebuild.
1. The afore mentioned vacuum leaks.
2. Accelerator pump. Shot volume.
3. Oxygen sensor. This tells the computer that tells the CC Quadrajet what fuel mixture to use. Change out at 50-60k miles.
4. ACDelco 213-4547: ENGINE COOLANT TEMPERATURE SENSOR located in themostat housing. Helps the computer determine mixture ratio. Loose wire here can cause problems.
5. Choke opening up early, Electric element gets weak after time.
6. Is the mixture solenoid working / adjusted properly.

My bet is on the accellerator pump.
The reason I am suggesting these items is I just went thru the same issues with my 1984 CC Quadrajet. The carb has 322k mi. on it. As did the oxygen sensor, temp sensor etc. Accel pump, oxygen sensor made a world of difference.

HOPE THIS HELPS

your list is good ...especially the accelerator pump...this is a wear item for sure ...

brings back my issue I had with my engine not putting out the power it once had but with over 200,ooo on this 305 I figured it was just age of the engine ..

fuel pump was weeping a little so the smell of fuel was there at the pump ...not leaking yet...so on replacing when I compared the original to the replacement the new spring was strong and a forcefull movement where the old was not forceful the full throw of the pump arm ..well after that replacement I was impressed with all that hywy passing power ...big difference!