383 help needed...

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Pana.Mopar

Pana.Mopar

Duster Down Under
Joined
Apr 25, 2008
Messages
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Location
Sydney, Australia
Having an issue with my 383 at the moment... It's a mild engine, 484 purple cam, pocket ported heads, big valves, 10.5:1 comp, Eddy RPM intake, 750 Vac Sec and 3000 stally..

Problem I'm having is that when I put my foot down it get's up and boogies and once I get off the throttle it wants to stall or does stall. Is this a carb set up issue? If I blurp the throttle when under load it just wants to stall...

What am I missing here???
 
probably a vacuum problem.
make sure you have everything connected properly to the carb

for a holley it's power brake in the back
distributor vacuum advance right side by the front near the top
pcv is at the front bottom
the other at the front bottom i think is for other vacuum things like cruise control/other things that need a vacuum source like to open hood scoops, etc.

any of those not being used should be plugged!
 
Could be your centifugal timing advance is sticking at max. advance position and essentially keeping the timing to far advanced as engine RPM comes back to idle. Also (if you're using it) make sure that the vacuum advance is operating correctly in that the plate within the dizzy is rotating smoothly from stop to stop.
 
If your not leaking air anywhere.........

Raise the idle slightly. It kind of sounds like it is starving for air after you get off of it. IDK

Good idea Terry.
 
Idle is currently set at approx 900rpm at idle ad about 600-700rpm when under load. Will raise timing a little. As far as I can see vacuum lines etc are all fine. Will check them again tonight and see how we go..
 
What kinda fuel pump do you have and how big are your fuel lines? Get minumum 3/8 inch lines and a increase rate fuel pump.
 
Also check you tank, If you have the original tank it may be filled with rust, I had a barracuda that did something similar and it was filled with rust, new tank and I was good
 
HOTRODSATHER said:
What kinda fuel pump do you have and how big are your fuel lines? Get minumum 3/8 inch lines and a increase rate fuel pump.
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you cant tell him to jack up the fuel pressure without knowing where it is at. have you seen what excessive fuel pressure will do?
 
(you cant tell him to jack up the fuel pressure without knowing where it is at. have you seen what excessive fuel pressure will do?)
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Yes I can. OK, so my reply lacked detail. If he is using small *** stock fuel lines and pump than going one step up wont hurt anything, and giving his engine description Id say he would require a more power fuel delivery system. You make it sound like I told him to strap on 15 of the most powerfull electric fuel pumps he could find and plumb them through some exhaust tubing...I think the OP would understand to what degree I was suggesting a fuel system upgrade...
 
A fuel system upgrade is something I would agree with on a "2 do" list, but, IMO, I do not think it the issue. Blockage at the tanks end is certainly possible though.

I'm just thinking, maybe the idle was low, not enuff throttle plate was open. Other advice given here seems to be good so far. There's a small host of items to go through. I wonder how this guy made out.
 
it runs well with his foot on the gas... wont idle.

could be a flakey fuel pump, or the timing is way retarded. or a vacuum leak like i posted before.

if i had to guess, i'd say it's probably a vacuum leak or timing problem. maybe a fuel pump but it would not run well under load
 
If it ran ok before and the distributor wasn't changed, timing may not be the issue. Kinda sounds like a carb thing. Instead of goofing around for ever just change the carb and see what happens. Anything can go on them. They get all kinds of air leaks even around the throttle shafts. The plates that screw to the shafts can come lose. Like many others, I have commented on similar things, and rarely do we get any feedback as to whether the problem was solved or not. When I first read this I thought something is missing here. It would be great to know the final outcome of this.
 
HOTRODSATHER said:
Yes I can. OK, so my reply lacked detail. If he is using small *** stock fuel lines and pump than going one step up wont hurt anything, and giving his engine description Id say he would require a more power fuel delivery system. You make it sound like I told him to strap on 15 of the most powerfull electric fuel pumps he could find and plumb them through some exhaust tubing...I think the OP would understand to what degree I was suggesting a fuel system upgrade...
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ya you are right, you can tell him anything you want to, BUT,CLEARLY if there is no issue with acceleration then it is NOT a fuel pressure issue or a fuel line diameter size problem, otherwise it would be running out of gas and misfiring and/or dying under load. my 360 with an electric pump set at 5.5 PSI using 5/16 fuel lines feeding my 650 holley DP has PLENTY of fuel pressure and the issue the OP is having is a carb problem or timing problem ,NOT a fuel pressure issue. i think your brake light fluid is low.:eek:ops:
 
Since I have tweaked the advance curve in my distributor (2 light springs and shortened the advance in the plate ) and switched the springs in my Eddelbrock carb ( metering rods ) it runs very well ! Sorry I have had too many bad problems with holley carbs ,been using Eddelbrock and trouble free . Just my 2 cents .
 
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