Engine Chasing a badly idling/dying engine.

ziegenfuss

New Member
Feb 20, 2022
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Decatur, TX
Morning Everyone... I'm new here. I recently purchased a 67 Coupe that was made... Eleanor-esque.

C-Code original 289
Holley 4160
Auto
No AC,
Manual x4 Drum Brakes,
Manual Steering,
FOUR hood pins (because who doesn't love removing the hood (thankfully, it's fiberglass) every time you want to do anything under there?) and lots of other stuff...

Car had sat for a couple years with routine starting before I bought it. Drained old gas, added new high-test, pulled and had carb rebuilt. (including new power valve.)

Pulled the plugs... black as my soul. Replaced.
Pulled the original coil... replaced with mst.
Pulled points... replaced with pertronix.
Tuesday or so I'll be replacing the spark plug wires. Then new valve cover gaskets.

Here's the thing...
It starts! It Idles... sort of. Goose the throttle when it's warm, it stumbles and/or dies. Put it in gear and... dies. Keep the RPMs up and it'll go, but, come to an intersection, stop sign, etc, and... dies.

On the vacuum gauge it's reading about 15 bars, +/- 1 inch hg.

I'm scratching my head here. Can't adjust the idle or mixture if it won't stay idling! Can't keep it idling even when running really rich (which it was before, due to blown power valve and a way weird metering block (both replaced during rebuild.)

Anyone have any ideas?
 
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Realmongo

I prefer to be called "Evil Genius"
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Oct 10, 2001
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Sounds similar to the problems I have with my antique Ford farm tractors.
My problems can be traced back to the ethanol crap that is blended into gasoline that requires frequent carb overhauls because that stuff sit in the passages and gums everything up.
 

manicmechanic007

5 Year Member
Sep 26, 2017
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Roy, Utah
ziegenfuss,
You need to see what happens when you cause a vacuum leak
Does it speed up or slow down/stumble?
Also there may be a piece of crap or gunk in the idle mixture screw ports. The ignition timing might be off (could be several things)
Count the threads (screw them in first counting the threads) then remove the mixture screws and blow them out (the ports) with compressed air
Then reinstall the mixture screws and retest if it idles or not
Check for a vacuum leak around the carb base and the intake manifold gaskets area
Good luck report back
 
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ziegenfuss

New Member
Feb 20, 2022
3
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Decatur, TX
ziegenfuss,
You need to see what happens when you cause a vacuum leak
Does it speed up or slow down/stumble?
Also there may be a piece of crap or gunk in the idle mixture screw ports. The ignition timing might be off (could be several things)
Count the threads (screw them in first counting the threads) then remove the mixture screws and blow them out (the ports) with compressed air
Then reinstall the mixture screws and retest if it idles or not
Check for a vacuum leak around the carb base and the intake manifold gaskets area
Good luck report back
Carb is solid--no vacuum leaks. mixture screw/ports are clean and clear. If I remove a port plug, the idle speeds up.
 

hungrymonkey

White by Birth, Trash By Choice
Founding Member
Nov 29, 1999
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Oregon.
Did you pull the distributor for the pertronix upgrade?

Given the info you provided, it could be a bunch of issues or combination of issues.

I'd start with timing, but it could be a vacuum leak, fuel system, carb, etc.

Fwiw, I usually try the cheapest thing first and progress from there.
 
Since the car is new to you, start more basic with the diagnosis. I would pop down to Autozone and borrow a cylinder compression gauge. One or more low cylinders could create this problem, and as some have suggested, do the cheapest thing first; “borrowing” that gauge, that’s free. If you get consistent cylinder pressure, great. Post the results so those more knowledgeable can help. That turned out to be my problem after I spent >$200 to fix my problem, all along, none of that helped.
 
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