440 hesitates off idle

[WVUFELLA]

SO if it is black ... does that mean smaller nozzles ? If it is to lean... bigger nozzles? Also i played with timing some more last night i bumped it back to 10*... at idle it sounds better and still starts easy .. but the hesitation is still there....i want to get a fuel press gauge even though i dont think that is the problem i want to 100% rule it out...

[WVUFELLA]

fuel pressure at idle is supposed to between 6-8 ? how much will the guage drop when i rock the throttle...

[Chryco Psycho]

fuel pressure is not the problem , the carb has fuel in it & it would take 45 seconds to run the carb out of fuel the hesitation is instant , black is too rich white is too lean , check float levels

[ek3]

You are correct but it is hard to hear if and when the engine hesitates/backfires/ when the engine is off Thanks jamiez... when i upload videos from my phone i dont know how to cut and paste a link onto the forum ... i have to wait till i get on a puter....Will try to check plugs tonight.... black is to rich and _______ is to lean?

  you are correct but, we already know the engine hesitates ,we just wanted to know if it ws getting a good shot of fuel ....

[ek3]

on the bottom of the baseplate there is 1 hole and slot per side  . one is the idol mixture hole [feeds fuel from side screws ]and the other is sort of a long square shaped slot that feeds fuel for transfer  from idol up to  say 2200 rpms -then the  boosters take over . . if you look at the bottom of the carbs throttle plates , you should be able to see the square shaped slot and it should look "even " [about the same size in each direction] the throttle plates should cover up the rest of the slot. if it does not ,then you loose signal and no fuel can flow from the transfer slots.. -ie.-  if it is a lot  longer than wider that will cause a bog like you have also.   

[1970 RT Challenger 1970]

How did the engine run before?

What did you change or do different?

Sometimes you have to undo what you did and retrace your steps backwards to find your way home on a problem.

A little change can cause a big unwanted change.

[WVUFELLA]

Good call 1970 here we go..

When i got the car it had a 800+double pump carb on it and a torker intake ... when we pulled engine  I had heads checked  and a 3 angle valve job done  compression was checked  and with the trw dome top pistons it was around 10.3/1 ( which i understand is close to the max for pump gas) anyways had new valve springs and new valves put in .... read on the forum that holley dominator intake was the best so i put one of those on it ....and everyone told me a 800+ double pumper wasnt needed so i put a 770 street anvenger on it.... when i started the car up the old cam was so big the car wouldnt idle in gear without feathering the thottle....all i remember about old cam lift over 510... individuals then said cam was to big for what i wanted to use it for.... So after reading on here i ended up goign with a lunati 337a1 camshaft 485 lift blah blah blah.... now it will idle in gear fine but has the hesitation.... does any of this help

[sprecks]

I'd be putting the 800 back on it and see what happens....

[WVUFELLA]

Don't have it anymore...sold ittraded it junked it it is gone.....im to cheap to buy a new just to see...figured people were right about it being to big so went smaller

[73restomod]

Try using a different timing hole on your pump cam. Some of them have 3 most have 2. I had the same problem with the holley on my truck. Switched to a orange? I think. I had to use the earliest timing hole. My truck had a pretty tame camshaft, and it was causing a lean spot just off idle. I switched to a more aggressive ramp cam and used the early timing setting. Problem solved.

Sent from my DROID RAZR using Tapatalk 2

[WVUFELLA]

I had a blue pump cam  and bought the pack of all the cams... i read where the pink cam is the most agressive for the 30cc pump shot so i put it on .... but good idea on changing the timing holes? i will try that

[HP_Cuda]

Let's start by putting the idle screws all the way in and then back each of them off to 1.5 turns.

The black cam is the largest shot in the holly lineup and then you can go to the 50cc accelerator pump if you want. It does look like you have enough pump shot. When you pull the throttle is there any play between the accelerator pump arm and the nut? If so take it out.

Otherwise, I want to know what kind of spring you have in your vacuum diaphragm assembly. I had a similar experience and after exhausting all other avenues I found that a shop had taken my regular "clear" spring and replaced it with a black spring, which would prevent the secondaries from ever opening at low throttle. Once I replaced that spring back to the stock one, she ran like a champ. Gotta love thieving shops.

[MEK-Dangerfield]

My take is it's your accelerator pump squiter.

You have a 31 in there, but that didn't work for me either. Try a 33, and I'm sure you will see a difference.

[WVUFELLA]

well i tried  a 33 then a 37 and still the same problem...so i called holley and they wanted me to check the power valve... Street avenger comes with standard 6.5... so i chekc the vacuum last night it was at 11 inches with car in gear at idle... whihc in holley terms equates to a 5.5 power valvwe ... my question is  doesone size power valve make that big of a difference? also what happnened to the bolt on and go with two adjustments.... idle screws, floats, power valve, nozzles, pump cam , pump lever arm, idle screw..... they must have meant you have to adjust all of those items twice? anyways still have the problem... yall recommend changing out power valve.... ps i have the silver spring in the vacuum  diaphragm

[HP_Cuda]

The silver spring is the stock one so you are set from a vacuum secondary standpoint. I would recommend putting it back to stock and see what happens.

B