6 pak slow return idle/poor throttle response

[747mopar]

I'd try more advance myself, I have a fairly mild cam in mine and it's a complete dog with any less than 30 degrees initial. I have my initial set at 20 then 10 more degrees pulled in by vacuum advance as soon as the motor fires by hooking it to manifold vacuum, total is 40 degrees. I've been running it for 5 years with zero problems, starts easy, revs quick, no pinging... On the slow to return to idle issue, have you tried manually returning the throttle to eliminate the possibility of it being in the cable?

 

[Paul_G]

On the slow to return to idle issue, have you tried manually returning the throttle to eliminate the possibility of it being in the cable?

Great idea. I have had this problem before. Disconnect the throttle cable and see what happens.

 

[tak419]

I'd try more advance myself, I have a fairly mild cam in mine and it's a complete dog with any less than 30 degrees initial. I have my initial set at 20 then 10 more degrees pulled in by vacuum advance as soon as the motor fires by hooking it to manifold vacuum, total is 40 degrees. I've been running it for 5 years with zero problems, starts easy, revs quick, no pinging... On the slow to return to idle issue, have you tried manually returning the throttle to eliminate the possibility of it being in the cable?

IveI tried that..but that was a good thought.

 

[tak419]

The weights in the distributor loom heavy and the spring is are purple.

 

[AR67GTX]

i think you are referring to the idle solenoid that deactivates on shut down to completely close throttle plates to help with stopping dieseling. used mostly for stock appearing setups. as far as i know it does not ease the throttle back to idle. it is used instead of the idle speed screw.
View attachment 634518

That one does look like an idle solenoid. We just ended up putting a dashpot ($175 +/- dollars for a strange contraption) on a 69 Hemi and I had noticed something similar on pictures of original six pack cars and thought it was the same thing. But now that you point it out - I do remember the six pack cars had idle solenoids. Damn - it's miserable getting old and forgetting stuff.

 

[tak419]

A little update. I notice the accelerator pump leaking so before going much farther and burning my car up I decide to pull the carb and fix it. Once removed I notice a rear bolt on the front carb is loose. I wonder if that's my vacuum leak I've been looking for ?

 

[Dennis H]

No 6 pak experience. Friend has a 6 pak 'Cuda. Epic multi month effort to tune it right. Throttle issue on mine was the alignment of the throttle cable. A bracket bolt has loosened.
This drivability issue is most important to me. Reason the 09 6 speed Challenger is PIA to drive is the throttle. Awful, slow to return and a mind of its own. I simply don't drive it much. I blame emissions and other annoying reasons. Throttle snap back and required pressure is everything for driving pleasure.

 

[tak419]

No 6 pak experience. Friend has a 6 pak 'Cuda. Epic multi month effort to tune it right. Throttle issue on mine was the alignment of the throttle cable. A bracket bolt has loosened.
This drivability issue is most important to me. Reason the 09 6 speed Challenger is PIA to drive is the throttle. Awful, slow to return and a mind of its own. I simply don't drive it much. I blame emissions and other annoying reasons. Throttle snap back and required pressure is everything for driving pleasure.[/QUOTE

It's not a cable issue.

 

[Officer Higgins]

I have heard of this method long ago and forgot about it. Good information

 

[tak419]

So far I found a carb with a loose mounting bolt, possibly the vacuum leak issue I'm hoping, and my accelerator pump was adjusted too tight. Haven't fired it up yet but thinking I'm finding my issues.

 

[mac]

after getting your carb issues addressed, i would still recommend more initial timing.

 

[tak419]

Cleaned the carbs, put back on car, primed with fuel and it fired right up. Someone explain this cause I'm baffled. The outer carb linkage is unhooked, the vac advance unplugged. I didn't realize the vacuum advance hose was not plugged with anything so note that fact please. Outer carb adjustments all 1/2 turn out and center 1 3/4. Timing at about 12*. The car was cold so choke on. It fired right up, idled a few seconds and a throttled on it a few times to kick the choke off. The car responded crisp like it should. Once it warmed up it started loosing the crispness and again slow to idle down but not real slow. I upped the timing to 17*, now car not wanting to fire up instantly (may be bad gas). I adjusted center carb screws to highest vacuum which is a smooth vacuum and about 15-17. One screw out about 2 turns other about 3 1/4. Still needs tuning. And have noticed accelerator pump not squirting now. That I believe in the check umbrella inside has went bad. Will fix that. But why when cold was it crisp ? I'm wondering if part of it loosing the crispness was the accelerator pump umbrella going bad. When I reassembled the carb the umbrella valve seemed loose. I pumped the rod and there was vacuum on the port. I'm wondering is when the gas filled back into the carb it had a chance to run properly for a few seconds before the umbrella swelled up and was letting gas back into the bowl or is there another reason the car would be super crisp running when cold....any thoughts ?

 

[Paul_G]

When the choke is closed/partly closed, the carb is supplying more fuel than air, it is running rich. In this state, on tip in it is getting just enough fuel to raise RPM quickly. If your accel pump is not working, when the choke is open it is extremely lean on tip in. It should bog without that extra shot of fuel from the accel pump. Need to fix that before you continue.

 

[moper]

Check to make sure the outboard gaskets are not hanging up the throttle blades, and I'd check the MP distributor to see where the centrifugal starts coming in and what springs are in it.

 

[tak419]

Check to make sure the outboard gaskets are not hanging up the throttle blades, and I'd check the MP distributor to see where the centrifugal starts coming in and what springs are in it.

Has the purple springs.

 

[tak419]

Just checked outboard blades are closing completely.

 

[BSB67]

When the choke is closed/partly closed, the carb is supplying more fuel than air, it is running rich. In this state, on tip in it is getting just enough fuel to raise RPM quickly. If your accel pump is not working, when the choke is open it is extremely lean on tip in. It should bog without that extra shot of fuel from the accel pump. Need to fix that before you continue.

Said differently, When the choke is on, it is hiding the lean condition that you have.

 

[mac]

i good order of business for now is take care of all the mechanical issues with carb, setup ignition curve, then adjust carbs for idle mixture. this is assuming the that all 3 carbs have the float level verified.

 

[moper]

I'm not up on the purple springs - are you referring to the ignition or the vacuum pods for the outboards? I'm talking about the distributor. Easiest to just use a timing light and timing tape, or a light with the advance function to check it.
It sounds like the carbs should be rebuilt completely. Freshen them up - Holleys are well known for needing rebuilds at fairly quick intervals and 6bbls are nothing special in that regard. The idle mixture screws should be out evenly. If they are not, you have an issue you're missing. Look at the cylinders that side feeds and see if the plugs show any signs of being lean. Maybe an intake leak on that bank?

 

[tak419]

Was referring to purple ignition springs. Carbs have been gone thru. Pulled plugs and they're all the same, none lean. I'm gonna get my accelerator pump issue fixed and go from there.