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Discussion Starter #1
Nova Folks-

I am in need of assistance with finding the cause of a miss I am have at acceleration. I have a small block with a Quick Fuel carb and when I accelerate the car has a bad miss. Once pass the miss the car really moves. I have checked to make sure all spark plugs wires are connected, checked to make sure all cylinder are firing (squirted each header tube with water), and made sure no spark plug wires are not bring burned by the headers. The car has no MSD system just a an HEI distributor. The car has a bad miss when you put it in gear and stall it up.Has any of my fellow Nova folks had this issue? Really banging my head against the wall. Thanks for your time!
 

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What do yo mean by.... "The car has a bad miss when you put it in gear and stall it up."
Is the car moving when you do this?

Can you provide some additional info:
*Is this a new problem you are experiencing?... did you change anything on your motor recently?
*Have you done a compression check? (always a good idea when troubleshooting engine problems)
*Do you know what type of cam profile (lift/duration) is installed in your engine?
*Are the valves adjusted correctly?
*Can you check the timing and post some numbers.
- Initial (no VA)... and at what RPM
- Total Mechanical (no VA)... and at what RPM
- Initial + VA* (* is VA connected to a full time vacuum source, or a ported vacuum source?)
- Total Mechanical + VA
-What is your vacuum level at idle?
*Can you confirm that you have 12 volts in the wire connected to the BAT terminal of the HEI (this wire should also be at least 12 guage).
*What size spark plug gaps are you running? I recommend about a .035 gap (even when using a HEI).

Be sure to also check you carb's float levels. If the the floats are set too high, it could be temporarily flooding the engine as the carb moves during acceleration.
 

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If you are talking about the car stumbling when the pedal is mashed it may be something as simple as the accelerator pump being out of adjustment. If it stumbles when you mash the gas and clears up that's the first place I would look. If it sits at idle and misses I would start at the basics and check spark plugs, wires and distributor cap. Could also be a vacuum leak to make it miss down low but clears up once the rpms get up a little. Need to know if it's a miss or a stumble.
 

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Discussion Starter #4
Thank for the feed back. I will look into all of the areas suggested. My issue may be more of a stumble that a miss.
 

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I agree with g2072 that if you have an engine stumble, hesitation or bog (almost feels like the engine pauses) when you quickly push on the accelerator pedal... but then the engine recovers, it is most likely too small size carb squirters and/or carb accelerator pump adjustments. I also agree that it is a good idea to check for vacuum leaks

Can you provide more details of exactly what you are doing... and what is happening when you are experiencing your issue. Ignition timing specs (as previously requested) would also be helpful information.
 

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Hi there . . . is it the stock HEI dist. ? replace your dist ignition module . Even a new one can be bad . . . . . simple , then test drive . You can't see if they are bad , or going bad
. . . . just buy another good one . just my 2cents . . . . .
 

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What carburetor does it have? Some are prone to stumble Carter AFB and Edlbrock which are basically the same design.. I’ve had several Carter AFBs and they would stumble/hesitate if you jumped on the gas a little too aggressively from an idle to take off.. Also, how old is your fuel..? Old gas will make it run like crap.. There might not be anything wrong at all.. Your chasing ghosts with bad gas..
 

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Discussion Starter #10
Real good feed back. @ Nova Thug - It has a Quck Fuel carb on it. Also the gas in the car is pretty fresh / @ Twinshadows - I will look into replacing module / @ Rifraf - the timing is set at 36 and the stumble happens when you accelerate leaving a light. I cleaned the front air bleeds last night with carb cleaner and the car idles better and is more responsive. I will be test driving it today and trying a new air cleaner and see what the out come will be.
 

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Great - - - I sure hope it all works out .

BUT, would you please post up u'r repair / or ' fix ' . . . just what helped your problem .
So many people just fix things & then we sometimes don't get any "feed-back" .

later, jim . . . . . Thanks .

ps .. I even had a friend that his car (GM) had a miss - - - and, he had said that he had just replace 'his ignition module' and the miss was still there. Another friend
& I (all 3 of us) , took his car for a test drive. We both told him - - - bad ign. module - - - it was . So, even new ones get tossed around , I'm just saying ……….
 

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The timing is set at 36 and the stumble happens when you accelerate leaving a light.
Is 36° timing your initial at idle?... or is that your total mechanical timing?

Is the engine stumble more like a quick bog/stall on an aggressive start, but then revs normally?
... or does it sound like the engine is "coughing" on an aggressive start and trying to clear itself?
 

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Discussion Starter #13
Evening folks, I tried another air filter from another car in the shop and stumble seems to be gone. Order a new filter from Summit. I may go a head and change the module as well. I will have better confirmation once I put it on the freeway.
 

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Nova Folks-

I am in need of assistance with finding the cause of a miss I am have at acceleration. I have a small block with a Quick Fuel carb and when I accelerate the car has a bad miss. Once pass the miss the car really moves. I have checked to make sure all spark plugs wires are connected, checked to make sure all cylinder are firing (squirted each header tube with water), and made sure no spark plug wires are not bring burned by the headers. The car has no MSD system just a an HEI distributor. The car has a bad miss when you put it in gear and stall it up.Has any of my fellow Nova folks had this issue? Really banging my head against the wall. Thanks for your time!
hi what year is your car . If it is pre 72 and your using hot wire from coil powering your hei. The original wire only puts out 8 volts and you need to run a new new power line to your hei make sure its power on when key is on. Your hei needs 12 volts to work properly . Start there see if it helps.
 

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One thing you could try to confirm or eliminate a spark problem is to hook up your timing light and carefully route the timing light leads back to the rear of the hood and into the car so a passenger can hold the light and actually watch the light as you are driving. If the light "misses" as your engine does you know the spark is intermittent. I've done this in the past with motorcycles and cars and it works very well
 

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Discussion Starter #16
Folks appreciate all of the input. I put a new K & N 4" air filter and made some passes and the car seems to be on point. I had a 3" K & N filter on before Really weird that a filter would cause a stumble.
 
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