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car stalls at full throttle????

Started by 68chargerboy, July 22, 2009, 09:29:12 PM

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firefighter3931

A lean bog is tunable by adjusting the accelerator pump circuit as mentioned by Ghoste. The carb may need a larger squirter to increase the pump shot.


Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

SeattleCharger

    these guys know a lot, so if they are routing you to carb tuning, then that's probably the problem,  hope you find someone at the cruise to help or that can point you to a local mopar club or something


Why would you want anything else?  Just give me a Charger and I'll be happy.

68chargerboy

well i tried a stiffer secondary spring..... no luck with that so im going to mess around with the accelerator pump today to see if i have any luck with that.  ill keep you guys posted

Zach

Purple440

Zach I had the same problem with my 800AVS and I tuned it out by tightening the secondary spring.  The carb is too big which is probably why that worked.  I had to keep tightening until I found the sweet spot, and not only did it solve the stalling, but it all around is much crisper on the throttle.

g/l 
:cheers:

Ghoste

There are some links in this thread that may be of some help.
http://www.dodgecharger.com/forum/index.php/topic,59697.0.html

Although 770 and 800 cfm are on the large side, they are not extremely large for a stock 440 and without mechanical secondaries, the secondary circuit shouldn't be a major contributor to your troubles unless it's way out.  That's major contributor, I am not trying to downplay it's importance or the size of the carb in any way.  I don't want to oversimplify this but if the secondary opens too quickly, the other thing that is happening in addition to stalled airflow is a lean condition, that is why a lot of the symptoms are the same.  Try tuning the pump a little and see if it changes, it may not or it may but it will be one more thing to check off the list.
(needs more gear and higher stall ;) )

68chargerboy

Quote from: Ghoste on July 25, 2009, 12:47:55 PM

(needs more gear and higher stall ;) )

hahaha i would love too and plan too the only thing holding me back is i have to save some money up first.  so i fiddle with the pump and not too much change.  i dont have any new cams in my garage so that may be why its hard for me to tune it right.  but ive been hearing alot that the carb is most likely too big for my motor so should i just put on one of the 650 (its a double pumper too so i think the lean situation would be worked out as well)? thanks

Zach

Ghoste

The less airflow can go a long way to clearing up a lean spot.  You could go the other way too with the dp (although Ron is on a mission to see that all Mopars are equipped with dp's  ;D ).
Get to it and have fun.

68chargerboy


68chargerboy

should i use my 1'' carb spacer or no???

b5blue


firefighter3931

Quote from: 68chargerboy on July 25, 2009, 01:24:39 PM
should i use my 1'' carb spacer or no???


Zach, what type of spacer are you using....4 hole or open ?

What is your timing set at ? How much at idle and how much total ? Are you using vac advance and if so is it using ported vacuum ?



Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

68chargerboy

Quote from: firefighter3931 on July 25, 2009, 01:53:04 PM
Quote from: 68chargerboy on July 25, 2009, 01:24:39 PM
should i use my 1'' carb spacer or no???


Zach, what type of spacer are you using....4 hole or open ?

What is your timing set at ? How much at idle and how much total ? Are you using vac advance and if so is it using ported vacuum ?

Ron,
its around 18 initial and 37 total.  it did have vacuum advance untill i put on the 650 dp.  talk about a night and day diffrence, still a slight bit hesitant but my floats are way out of wack.  im having a total brain fart today which way do i turn the screw to add fuel to the bowl? and i am using a open spacer.
  Zach
Ron

68chargerboy

dont know why but the new stuff i said was also in the quote somehow??? idk lol

b5blue

The nut adjusts height not the screw.Counter Clockwise = up  :2thumbs:

68chargerboy

ok so i adjusted the floats, thanks for that help. nowww if its not one thing its another.  now i am having exhaust pops i know its when its ideling for sure but not too sure about under load, under load it seems good but pops when its sitting idle in my drive way.  what is the caused by???

b5blue

No snap or crackle....just pops.... :shruggy: like in backfire?

68chargerboy

DONT YOU JUST LOVE A HARD LAUNCH!!!!!!!! finally!!!!!  :icon_smile_big:  for whom ever is interested it turned out to be too big of a carb for the engine combo.  770 is evidently to big for a mild 440 the 650 works beutifully.  as for the exhaust pops spent a little more time tuning and setting my fuel pressure and all the other goodies and the pops disappeared.  finally i have what i wanted for sooo many years lol  thank you every one for all of the help on this thread as well as many others that i have had over the years during my process  :2thumbs: 

ps its a muscle car so im sure ill have many more problem threads to come hahaha

Zach

SeattleCharger

awesome, just in time for your cruise tonight,   keep her between the lines   :2thumbs:


Why would you want anything else?  Just give me a Charger and I'll be happy.

maxwellwedge

In my experience over the years a 780 vacuum is a perfect street carb for any 440 if adjusted properly. On a properly tuned carb the secondaries aren't coming in until the engine wants it and may never open fully depending on the spring. 440 cubes is a lot of cubes that pump a lot of air. Sounds like accelerator circuit trouble to me. GM put 780's on small blocks all day long.

firefighter3931

Quote from: 68chargerboy on July 25, 2009, 02:17:26 PM
Ron,
its around 18 initial and 37 total.  it did have vacuum advance untill i put on the 650 dp.  talk about a night and day diffrence, still a slight bit hesitant but my floats are way out of wack.  im having a total brain fart today which way do i turn the screw to add fuel to the bowl? and i am using a open spacer.
  Zach



Good work Zach....timing is perfect for that cam profile....good work !  :2thumbs:

You beat me to the next question regarding vacuum advance.....blocking it off was going to be my next suggestion.  ;)

It sounds like you've got it pretty much dialed in....the open spacer will help compensate for the smaller (650cfm) carb so i'd leave it on there.  :yesnod:



Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

Purple440

Quote from: Ghoste on July 25, 2009, 01:04:21 PM
...(although Ron is on a mission to see that all Mopars are equipped with dp's  ;D ).

Yes he is!  lol

:cheers:

Nice work Zach!  Glad to hear it's running great now.  :2thumbs:

b5blue


Ghoste

Great to hear it's running good now.  :2thumbs: (although I still think the 770 could be made to work well since less airflow from smaller carb plus more fuel from double pump = no lean spot :icon_smile_wink:)  With the 650 you should have great throttle response now too.

68chargerboy

Quote from: Ghoste on July 26, 2009, 11:41:42 AM
Great to hear it's running good now.  :2thumbs: (although I still think the 770 could be made to work well since less airflow from smaller carb plus more fuel from double pump = no lean spot :icon_smile_wink:)  With the 650 you should have great throttle response now too.

ohh yea makes it way more fun to drive stop light to stop light on the way to my cruise nights :icon_smile_big: