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  #1  
Old 04-08-2009, 03:19 AM
coronetcustom coronetcustom is offline
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Default engine stalls on full throttle

hello,
what could be cause and cure for engine stalling completely when pressing gas pedal fast to full throttle? i changed acceleration pump nozzle from size 37 to 45 and linkage to pump for most pump action, but no change. my own opinion is that it has to do something with advance timing and change in flow with new heads. i blocked all vacuum advance ports in carb and distributor and things got a lot better. this all started after i replaced stock heads into new edelbrock performer heads. it´s a 1971/383 engine car and has edelbrock 750 carb and performer intake manifold, also got mopar performance 272 hydraulic cam. distributor is mopar´s own electric with all it´s components and without any modifications(straight from the box) and orange ecu box. car was runnig normally before head change. now with ports blocked car runs pretty good and there´s noticable change in performance, but i would like to get things just right and all power into
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  #2  
Old 04-08-2009, 03:41 AM
TK TK is offline
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Default

The door on the sec is stuck open, or too light. I have added weights to lots of them)
metering rod spring is too light.
secondary jets are too big.
Float level is too high, does it die when you come to a stop hard?
And something is amiss if the vac advance being unplugged made a difference. From idle to a quick WOT, the advance is completely INOP.

Me thinks you had it hooked to manifold. (Right port facing motor)

Whats you idle timing? 12BTDC?
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  #3  
Old 04-08-2009, 10:34 AM
peg leg peg leg is offline
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Default Maybe

The new heads are flowing so much better that the fuel pump cannot keep up? Just a SWAG, but have someone watch the fuel pressure gauge when this occurs.
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  #4  
Old 04-08-2009, 05:30 PM
coronetcustom coronetcustom is offline
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stalling occured when driving moderately low speed to fast full throttle or from stand still to fast full throttle. no stalling when revving engine in garage, hard braking or on normal/easy accelerations. after blocking distributor vacuum hose and both carb ports stall problem went away. there´s still some slight hesitation. float levels are within edelbrock specs, secondary jets are factory set and i tried wide variety of metering rod springs from weaker to stronger, but no change. i had distributor vacuum hose in correct port in carb. i don´t think there´s problem with fuel pressure, but i´ll check it. reason why i´m suspecting timing/advance is because blocking ports and distr.hose made big difference to better. if i understand the operation of distributor correctly, advance works now only with counter weights? maybe i should try different set of counter weight springs?
to TK, what does "door on the sec is stuck open, or too light"?don´t know what it means. thanks.
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  #5  
Old 04-08-2009, 10:56 PM
Cudafever Cudafever is offline
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OK i thing we need a little bit more info if we are going to help.

describe a little bit more about it dieing out.

does it die like, the eng stops, if you keep you foot to the floor???


OR does it bog? (eng dies out and then snaps back to life about the time your face is about to Eating the wind shield----vvvvv^^^^^^^ )
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  #6  
Old 04-09-2009, 12:15 AM
BigBlockDude BigBlockDude is offline
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Sounds like a lean issue to me. Just my thoughts, too small accelerator pump shot, or secondaries open too fast.

What is your initial and total timing set at?
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  #7  
Old 04-09-2009, 02:51 AM
coronetcustom coronetcustom is offline
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before blocking vacuum ports and distr.hose as discribed above, engine stopped completely on fast full throttle-had to start engine again. after blocking them this problem went away. i cannot give accurate info on timing, cam is timed as instructed by manufactor and worked fine before head change. i don´t have timing light but timing can´t be completely wacked because engine revs crisp and sharp, starts great, doesn´t knock or backfire. i will take carb and timing tuned next week after easter.
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  #8  
Old 04-09-2009, 11:33 AM
passing you passing you is offline
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It's lean.
Take the timing away it gets better.
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