Carb issues

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dustya_383

dustya_383

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Location
san Jose Ca
Hey guys been a while since I've posted here but I'm currently having some issues with the duster.

So here is the 1st ...issue i can not get the car to idle .I am constantly popping hood and adjusting the throttle to to give car more gas otherwise it dies out .... Now once I get it idling normal I bring it down to about 1000rpm and it'll be fine (AT IDLE) but say I turn car off and start back up 20 mins later, idle drops to like 500 and will die if I don't give it gas and I have to readjust throttle again.

What is this issue and how can I resolve it ?

Now I have 2 other issues when I'm actually driving the car .

Now when I'm in 1st or 2nd gear just rolling say 15mph in a residential area the car will surge and jerk As soon as I remove my foot from the gas pedal. Car is a 4spd

Other issue is at WOT I kidnda have to rev engine high to get going or else it feels real boggy
When I get it goin it will sputter like it has lack of fuel. I could really use a hand here guys thanks


Duster
410 4spd
750dp proform
Timing 34* locked dizzy
323 rear gear
28inch tire

If anyone in San Jose /NorCal area is good with tuning maybe we can meet up
 
dustya_383 said:
If anyone in San Jose /NorCal area is good with tuning maybe we can meet up
Click to expand...

That's a great idea.

I always close my eyes and try to put myself in the car as if I'm driving it to try and "feel" what the issues are that's described, but there's nothing like being there.

My first thought in a situation like this always goes to timing? As far as the "drivability" part goes, I have to wonder if the locked out 34* is causing that issue being as the 3.23's and 28" tire makes cruising in the higher gears a really low rpm, and thus a lot of timing for that situation?

The starting/idle issue almost sounds like a "rich" problem.....like the floats being a little high?


I know you've posted hear quite a bit, but to be honest, I have a hard time remembering everyone's combo/issues. Hopefully I hit on something, but if not, i'll still keep a eye out if I feel that I can help.
 
OldmanRick said:
That's a great idea.

I always close my eyes and try to put myself in the car as if I'm driving it to try and "feel" what the issues are that's described, but there's nothing like being there.

My first thought in a situation like this always goes to timing? As far as the "drivability" part goes, I have to wonder if the locked out 34* is causing that issue being as the 3.23's and 28" tire makes cruising in the higher gears a really low rpm, and thus a lot of timing for that situation?

The starting/idle issue almost sounds like a "rich" problem.....like the floats being a little high?


I know you've posted hear quite a bit, but to be honest, I have a hard time remembering everyone's combo/issues. Hopefully I hit on something, but if not, i'll still keep a eye out if I feel that I can help.
Click to expand...


Thank you appreciate that .
And yea it's sometimes very hard to describe a drivability issue with out being inside the car feeling or hearing what's going on . I have noticed as of late the car has been running real rich "lately I can smell it. I recently but this carb on out if the box and it ran perfect for a while then started acting funny . I had an 850 do on it when the build was fresh and it ran almost flawless plenty of power no bog.(engine is almost at 3k now). But later ditched the 850. Maybe that's my whole issue there possibly a simple carb swap.... Also hooked up a vac guage and it bounces back and forth 8-10

Magnum 306s solid comp cam
555 lift int &ext 260@50 306duration


Another thing I adjust floats then they go all out of whack everytime I adjust them not sure how to get it right
 
Here's a vid to help adjust the floats

[ame="http://www.youtube.com/watch?feature=player_embedded&v=ge-mIk6nEYQ"]How To Adjust Fuel And Float Level On Holley Carbs - YouTube[/ame]

If you got a vacuum guage,, you may be able to get an idea of what wrong by comparing your vacuum guage actions to the ones on this link.. klik the green tabs for comparison guage actions

http://www.secondchancegarage.com/public/186.cfm

Failing that, pull and read all the plugs,,

hope it helps.. cheers
 
See what your fuel pressure is and make sure you have a good insulator gasket under the carb. You may also want to restrict the flow of exhaust through your manifold heat section. Do you have a regulator on it? Probably want to set it between 5 and 6 1/2 psi if you can for a driver with manifold heat.
 
There's a passage that crosses under the intake manifold plenum connecting an exhaust port on each
cylinder head to heat intake mixture. It's only necessary in very cold weather, or on a manifold
that has a choke stove. Your Holley needs to be kept as cool as possible to work properly. When
Chrysler put Holley carbs on as original equip, they had flapper valves on primary float bowl to let
boiling gas vapors escape into atmosphere. Also gas companies used to put additives in to fight
gas boiling and vapor lock. High pressure fuel injected vehicles don't have those problems. Use a
heat spacer under carb and block heat crossover under manifold.
 
dustya_383 said:
Now when I'm in 1st or 2nd gear just rolling say 15mph in a residential area the car will surge and jerk As soon as I remove my foot from the gas pedal. Car is a 4spd
Click to expand...
If you mean that this happens when you stop accelerating and back off the throttle to a cruise or coast condition in low gear, this is not uncommon for manual trannie cars of any type, and gets worse with steeper gearing and more torque. Heck, my /6 3-on-the-tree will do this some! Just push in the clutch. IMO, focus on the other issues.
 
As for the unpredicatable idle, I would also be looking at the throttle plate positions at idle for both primary and secondary. One cause of this type of idle problem is if the secondaries are not resting on the secondary idle stop becasue that stop is backed down too far, but are resting on the sides of the bore when the close to idle. You need to pull the carb and check the throttle stops and throttle plate positions when closed.

The secondary stop should be adjusted so that the secondary throttle plate edges are just barely off of the sides of the bore. Then check that the primary throttle plates are set so that the exposure of the transtion slots are 'square'. At that point, you are set to tune the idle circuits.
 
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