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You can fill the bowl from the vent, but it seems that the two paths, idle circuit and main metering (or primary) are not allowing engine vacuum to pull the fuel from the float bowl into the engine through the carburetor's venturi. It is possible that the float is set to low and not allowing fuel to enter the carburetor, but in the first video the engine started on fuel from the accelerator pump. The accelerator pump draws its fuel from the float bowl, so it would seem that at least some fuel is entering the float bowl. I would be looking for some sort of obstruction keeping fuel from being drawn into the engine. The easiest thing to do on the idle circuit would be to back the idle mixture screw out several turns. If that is the same carburetor that came with the car, and it had the same problem before you rebuilt it, I'd be looking for sediment plugging those two paths. Compressed air can do wonders to clear those paths, but you don't want to do that with the carburetor installed on the engine.
Yes, it's the same carb that came with the engine. I'll try filling the bowl via the vent (and open up the idle mixture screw a couple more turns) to see if that helps. I suspect pulling off the carb and blowing out the paths again is my next step, but I did that when I rebuilt it the first time...maybe I missed something.
You can fill the bowl from the vent, but it seems that the two paths, idle circuit and main metering (or primary) are not allowing engine vacuum to pull the fuel from the float bowl into the engine through the carburetor's venturi. It is possible that the float is set to low and not allowing fuel to enter the carburetor, but in the first video the engine started on fuel from the accelerator pump. The accelerator pump draws its fuel from the float bowl, so it would seem that at least some fuel is entering the float bowl. I would be looking for some sort of obstruction keeping fuel from being drawn into the engine. The easiest thing to do on the idle circuit would be to back the idle mixture screw out several turns. If that is the same carburetor that came with the car, and it had the same problem before you rebuilt it, I'd be looking for sediment plugging those two paths. Compressed air can do wonders to clear those paths, but you don't want to do that with the carburetor installed on the engine.
I removed the carb, checked the float level, cleaned out all the paths again, and re-installed. Same problem as before. It sure seems like root cause is the "resistor wire" issue you brought up initially...the engine starts with the ignition switch in the "Start" position, but it dies when moved to the "On" position. So I investigated this some more and realized that the car has been upgraded to the Pertronix Flame-Thrower coil and Electronic Iniition, so I think the "pink" resistor wire has already been bypassed (I don't see it under the dash) and 12V is routed to the coil. If this is the case, what could impact 12V when the ignition switch is moved the "Run" position? Could it be an ignition switch problem or bad wire?
I've attached pics of the my coil and distributor. Note that there are two wires connected to the firewall side of the coil...one goes to the firewall, the other goes to the distributor. Does this look correct? 1966 Mustang Coil and Distributor Wiring Pertronix Flame-Thrower Coil and Electronic Ignition
I checked mine, I have Pertronix also. It is also black wire to (-) and pink wire to (+). Do you have 12v to the + side of the coil with the ignition switch in "run"? It is very unusual that it did not continue to run when you jumper wired between the positive side of the battery to the + side of the coil. Yes, it could be an ignition switch problem. Power to the coil during cranking comes from the "I" terminal of the starter relay to the "Main disconnect" on the firewall - to the same pin the resistor wire goes too. Power comes from the "I" side of the relay while cranking but from the ignition switch while in "run". Take a look at the top of the diagram. The 262 wire coming off the starter relay powers the 16 wire to the coil while cranking. The 16A wire powers the coil while in "run". With Pertronix, the 16A wire is removed/bypassed/replaced with a non-resistor wire.
I checked mine, I have Pertronix also. It is also black wire to (-) and pink wire to (+). Do you have 12v to the + side of the coil with the ignition switch in "run"? It is very unusual that it did not continue to run when you jumper wired between the positive side of the battery to the + side of the coil. Yes, it could be an ignition switch problem. Power to the coil during cranking comes from the "I" terminal of the starter relay to the "Main disconnect" on the firewall - to the same pin the resistor wire goes too. Power comes from the "I" side of the relay while cranking but from the ignition switch while in "run". Take a look at the top of the diagram. The 262 wire coming off the starter relay powers the 16 wire to the coil while cranking. The 16A wire powers the coil while in "run". With Pertronix, the 16A wire is removed/bypassed/replaced with a non-resistor wire.
When the ignition key is in the "Run" position, there is only 9V on the +ve terminal of the coil. When I'm cranking the engine, there is 12.5V at the same +ve terminal. So it seems like the resistor wire was not bypassed when the Pertronix coil/ignition was installed, but unfortunately I'm unable to get under the dash to follow the wires. I re-tried your suggestion to run a jumper from the +ve side of the battery directly to the +ve side of the coil, but still no luck.
I've read other threads that say that if the Pertronix electronic ignition module is run using less than 12V for too long, it can get damaged. I wonder if that is what has happened to my unit.
Where did you bypass resistor wire on your car? Any chance you could take a picture of it? Thx....
You want me to show you my jenky sh*t? I'll get a photo or two, but the way I did it I'm not that proud of, at least not proud enough to recommend it as "a good way".
Going back to the wiring diagram, you see a #16 wire coming off the back of the ignition switch. That wire is red with a green tracer from the switch to a bullet connector. After the bullet connector that wire turns pink, the resistor wire. What I did is cut the pink wire and sealed it and tucked it up in the dash so that it can't short on anything. I took the bullet connector from the pink wire by prying the wire clamps on the connector apart and putting that side of the bullet connector on a new 18 gauge (or 16, I don't remember what I had on hand). I fed that wire through an existing small hole in the dash that a PO had run a lead to an Awooga horn. I ran that new wire directly to the coil.
I'm pretty sure I ran the wire through the dash before I sleeved a piece of shrink tube on it and then crimped and soldier the bullet connector. Then I pulled all the excess back into the engine bay before I cut it to length at the coil. The reason I used the existing bullet connector is because nothing mates up to the Ford bullet connectors other than another Ford bullet connector, and because of the difficulty working under the dash, I was trying to minimize the work I had to actually do in the dash. In the photo you can see the green wire, which is the one I ran to the coil, coming through a hole in the firewall with a white wire, which is going to the horn. You will also see the actual main disconnect just inboard of that. The resistor wire goes to the interior side of that connector. The proper way to do this would be to separate the disconnect, pull the inner part of the connector down to get the resistor wire unpinned, pin up the new wire that is plugged in to the bullet connector off the ignition switch, and put the main disconnect back together. But you've been under the dash and you know just how hard that actually would be to do.
It is also quite difficult to get the bullet connector apart as you can only get one hand up under the dash at a time. Cutting the pink wire so I could get the bullet connector down to where I could grab it with both hands really helped. Don't forget to disconnect the battery while you're working on the ignition switch wires.
I fried my first Pertronix coil, but I don't remember how. It is possible that there is a problem with your coil, it really should run when hot wired.
05-14-2024, 04:15 PM
