Electrical issue in engine circuit

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1971 Mach 1, Grabber Blue w/Argent stripes. Original 2V 351C Auto, Tilt, rear defog, Black Comfortweave Interior. Under restoration. Original colors, 4V 351C, 4-Speed, Spoilers, Magnums, Ram Air. All Ford parts.
Ok here we go again

351 c 4 speed car, fresh restoration, fresh engine. Holley 670 Ultra, Edelbrock Performer II LB intake.

Autolite distributor with points, original engine feed wire.

The car starts and runs good, and idles well.

Under lighter acceleration around 49 mph, there is a little hesitation and inconsistency in the driveability. When warm, I will have cut outs and backfires that kill the car. Only when warm, it will be real sluggish on starts from a stop and require a lot of over revving to get it moving. A backfire will kill it, then I can usually restart and go again.

Is this the sign of a failing coil? I have an original coil on the car. A bad adjustment on the vacuum advance?

It seems like the power blanks out as I will lose the radio too on the warm events.

Please help!

Kcmash
 

midlife

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Radio power loss is a significant clue. I'd check your battery terminals for corrosion, cables too! And ground points as well. With rising temperatures, resistance at poor contact points increases, lowering voltages.
 
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Man, what a kick to the groin. If you suspect main power loss, you’ve got to start at the battery terminals and track forward. I wish you luck.
 
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Midlife,

I get a super clean tone and low resistance when I check continuity on all my ground connections and positive connections.

It’s hard to tell if the radio is tied to the ignition problem or not. The ignition misfire is definitely tied to the car being warmed up, By warmed up I mean long enough for the fast idle to be kicked out. My engine temp stays at the low end of the normal range when warm.

Kcmash
 
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Backfires can be caused by a lot of things, but you seem to have more than just issues with backfiring, such as lack of power and what seems like loosing all electrical power to the vehicle. Backfires are usually caused by either a very lean A/F mixture or ignition timing that is way off. There are so many things to check that I don't know where to start. From your description of how the car does not want to accelerate without a lot of throttle when warm I would first check the float levels on the carburetor, easy to do on a Holey through the side bowl screws or glass. Check that your accelerator pump is working, when you accelerate the carb you get 2 streams of fuel coming out of your accelerator pump, just remove air cleaner with engine off, accelerate the carb and you should see two streams of fuel in the front venturi. Check that your fuel filter is not clogged, I have even seen fuel senders socks that will clog when tanks are old an rusty. Make sure your carb is getting enough fuel, those bowls should always be full. Check for vacuum leaks, check all hoses for leaks, PCV valve, brake booster leaking. On a cool engine, spray carb cleaner all around the carburetor and intake manifold gaskets to look for vacuum leaks. Make sure that at idle you do not have fuel coming out of the carburetor boosters, jut take air cleaner off with carb at idle and look down the front of the carb, you should not see any leaking fuel out of the boosters at idle. Then you have your ignition, a bad coil, points, or condenser can cause everything you are experiencing. First check how your points look and check your point gap. Many modern points will not last but maybe a couple hundred miles, the rubbing block are not well made and they will wear down in no time. Only buy Napa Echlin points and condensers, the stuff coming in from China is junk. I would just buy a new set of points and a new condenser, they are cheap. After you set your points check your ignition timing, too retarded or too advanced can cause backfires. You cannot trust your timing mark on these old balancers, a lot of them have slipped. Your whole issue could be as simple as you set your timing lets say at 10 degrees BTDC with your timing light, but the damper has slipped and you could be 20-30 degrees or more off, either ATDC or BTDC because the balancer slipped. Some people are really good at "power timing" and engine by sound and feel, but it takes a lot of experience. Now, anyone can just set the timing and advance it a bit and see how it runs, or retard it a bit and see how it runs. If you advance it too much the engine will not want to turn over when hot, you then know to retard it a bit at a time till it starts fine when hot. Check your distributor, make sure that everything is moving in there as it should and nothing is stuck. When you have the timing light on the engine and you are checking your timing, make sure to accelerate the engine to see that your timing is moving as it should. The coil is a tough one, the other day I tried to find a procedure to check a coil, but everyone everywhere has different OHM numbers of what a coil should measure across it, plus coils have different resistances, which will affect the numbers across the coil, and if you do not know the resistance of your coil, you are wasting your time. If after looking at everything you still have not found the issue I would just bite the bullet and get a new coil. Check your spark plugs and see how they are burning, that may give you a clue to what is happening.
What has me stumped is the issue of the electrical blackout, radio going off. I suck at electrical, but I have found some of these issues by having the engine running, and moving all the wiring around with my hands as it runs. If there is a break in a wire, you can usually find it by just moving the wires by hand, when you start moving the wire with a break in it, the engine will start acting up or stall. Check your coil spark output by removing the coil wire from the distributor and putting it close to ground, you should have a nice spark there. Check your coil wire, this is the one wire, that if it starts to go bad it can really wreak havoc on the engine. Check your cap and rotor. Check your points wire to the coil. Recheck all grounds, make sure that you have a good engine ground and a body ground. Check your battery cables and terminals. This is not an easy one to diagnose... could be so many things.
Just remembered another one that happened to me years ago with a car with low power and backfiring. A small piece of rubber fuel hose had shaved off a rubber line and had gone into the fuel bowl and had stuck itself inside one of the Holley primary main jets. Car idled fine and sounded fine at idle, would even run fine up to a certain speed, but as soon as you started accelerating it was low on power and would backfire. The piece of rubber in the jet had basically stopped fuel from flowing from one of the primary boosters. Found out what was happening when we took the air cleaner off and accelerated the engine while looking down the carb, one booster was flowing fuel in a correct fine mist, and the other booster would just leak a little bit of fuel in small droplets off it...
 
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Hemikiller

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Like Midlife said, the radio loss is an indicator that the issue lies in power delivery. You need to have clean and solid ground cable contact points. You can't simply do a continuity test on a circuit that sees many amps under load, you need to do a voltage drop test. That will help isolate where your issues lie.

Clean and re-seat the block ground connection, the apron ground point, and clean the battery terminals. Aftermarket parts store cables often don't have the battery-> apron ground connection, or the owner neglects to hook it up.

71ground.jpg



If you have the bolt together repair terminals, get new cables. Inspect the cables as you go a long, any signs of corrosion mean it's time to replace them. Verify the power connections on the battery side of the starter solenoid and the apron terminal block (if equipped) are clean and secure. Inspect the alternator harness, clean it's connections and replace if necessary.

If all of that is good, and the voltage drop test returns good results, then it's time to look deeper into the system. Coil is a possibility as it may fail once it heats up, but it won't cause your radio issue.

Quick example, did my first auto to 4 speed swap in '91 in a 71 302 sportsroof. Swap went off great, everything worked as expected and was done in a couple days. Car started having an issue with dying intermittently, and fouling plugs at random. Checked everything I could think of, replaced plugs, rebuilt and readjusted the carb, replaced points, condenser etc with no improvement. Found the apron ground connection was missing due to el cheapo parts store battery cable. Shoved a length of wire under the battery terminal and screwed it to a handy bolt, problem solved. My theory is the transmission cooler lines were acting as a chassis ground, as they were in full contact with the engine crossmember.


STARTER_VOLTAGE_DROP_TEST.JPG
 
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I know what it is now!

What would make the car and everything suddenly die! Not even a click from the ignition after dying, no power at all!

Well it happened again tonight. What I found is my toe is hitting the ignition switch wiring at times and it all goes dead. Tonight when it died I tapped the wire with my toe and everything came back.

So I know where to look anyway.

Kcmash
 
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I know what it is now!

What would make the car and everything suddenly die! Not even a click from the ignition after dying, no power at all!

Well it happened again tonight. What I found is my toe is hitting the ignition switch wiring at times and it all goes dead. Tonight when it died I tapped the wire with my toe and everything came back.

So I know where to look anyway.

Kcmash
I know you found it by pure luck, but I have always found that when you have an issue like this the best thing to do, especially for electrically challenged people like me, is start moving all the wiring around until the vehicle dies. Strange that it was the ignition switch wiring, but hey at least you know where the issue is at now :)
 
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Like Midlife said, the radio loss is an indicator that the issue lies in power delivery. You need to have clean and solid ground cable contact points. You can't simply do a continuity test on a circuit that sees many amps under load, you need to do a voltage drop test. That will help isolate where your issues lie.

Clean and re-seat the block ground connection, the apron ground point, and clean the battery terminals. Aftermarket parts store cables often don't have the battery-> apron ground connection, or the owner neglects to hook it up.

View attachment 63784



If you have the bolt together repair terminals, get new cables. Inspect the cables as you go a long, any signs of corrosion mean it's time to replace them. Verify the power connections on the battery side of the starter solenoid and the apron terminal block (if equipped) are clean and secure. Inspect the alternator harness, clean it's connections and replace if necessary.

If all of that is good, and the voltage drop test returns good results, then it's time to look deeper into the system. Coil is a possibility as it may fail once it heats up, but it won't cause your radio issue.

Quick example, did my first auto to 4 speed swap in '91 in a 71 302 sportsroof. Swap went off great, everything worked as expected and was done in a couple days. Car started having an issue with dying intermittently, and fouling plugs at random. Checked everything I could think of, replaced plugs, rebuilt and readjusted the carb, replaced points, condenser etc with no improvement. Found the apron ground connection was missing due to el cheapo parts store battery cable. Shoved a length of wire under the battery terminal and screwed it to a handy bolt, problem solved. My theory is the transmission cooler lines were acting as a chassis ground, as they were in full contact with the engine crossmember.


View attachment 63781
Nice diagram, HemiKiller. re: voltage drop test locations and expected drop values. Cleanest such diagram I have ever seen. Worth saving in my little library. It is a too often overlooked area in a diagnostic approach.
 
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I know what it is now!

What would make the car and everything suddenly die! Not even a click from the ignition after dying, no power at all!

Well it happened again tonight. What I found is my toe is hitting the ignition switch wiring at times and it all goes dead. Tonight when it died I tapped the wire with my toe and everything came back.

So I know where to look anyway.

Kcmash
What good fortune on your part to have had such dumb ass luck! I have a similar story re: a 1973 Mercury Capri with a v-6 that belongs to a family friend and physician. He would drive along and suddenly the engine would die. He hd it at various Lincoln store (Los Angeles area) and Ford stores. The techs replaced everything, and I mean everything per the warranty copies, often the parts replaced had been swapped out more than once. Ignition coils, points, condenser, new spark plugs, distributor cap, rotors, carburetor, distributor, battery, alternator, ignition switch, fuses, fuel filters, fuel pump, fuel lines, even fuel tank, etc... This was definitely a "Hail Mary" shotgun repair effort made by the various dealerships, yet the problem persisted.

Well, my father (also a physician) really did not know to make of me, as I had by that time in life decided to go into auto repair for an occupation vs medical school. I had the chops to do medical school, but my interests were more akin to automobiles. He tried to put on a happy face for me, but I knew he was worried for me. Anyway, in an attempt to demonstrate his confidence in my ability in auto repair and braggingly told hie friend, "I bet Gilbert can fix it!"

So, there I was, given the Capri (5 speed manual, really nicely optioned) for as long as I needed, given $50 for gasoline, and told to ask for more if it was needed, and authorized to drive it as much as needed, to find the problem. And a "good luck" to boot. Me, in my first semester of junior college repair classes up against a problem the many technicians at several different dealerships had not been able to fix. And my father's reputation on the line. Yikes...

I ran it on an oscilloscope, everything looked good. The carburetor worked perfectly. The description of the problem screamed, "electrical." But everything was checking out, perfectly. Everything. But, I decided to persist. I had some advantages over what the various techs had. I knew what parts not to bother replacing because they had already been replaced, and I was not having to "beat the clock" in diagnosing and repairing the car. I could take my time, income generation was not an issue.

One early Saturday morning, on a day I was not scheduled to go into work, I decided to take the Capri out for a long drive down to Pacific Coast Highway and open it up to see how fast it was with the great running v-6. It was still early when I reached PCH, almost no traffic, and it was a nice almost bright morning with no rain or dew. I hit 118 MPH in one direction, turned around to do it again in the other direction. Funny thing, when I put the clutch in toe shift the tachometer went to 0, but when I released the clutch the tach provided a reading. I pulled into a parking lot and found I could suddenly replicate the problem. Clutch goes in, engine dies. Keep it in and I could crank the engine but it would not start and run. Clutch out and it started and ran perfectly, until I put in thee clutch again. I was able to replicate the phantom problem at will, a problem that had not manifested itself earlier all week long. I recognized this was a rare opportunity to locate the problem if my luck held out. With the engine running I popped the hood, and looked at the wires (I was now positive the problem was electrical.

I began to wriggle a few wires here and there, then I noticed a wire with a push-in connector laying on top of the clutch cable. As soon as I touched the wire the engine died! That was my first really big "Eureka!" moment in what would turn out to be a lot of such unusual problem resolutions over the next many years. I restarted the engine and repeated the moving of the wire, which lead to the ignition coil, time and again. I was convinced that was the cause of the problem. I pulled the cheaply assembled connector apart with the intention of twisting the end of the two wires connected together (away from any metal), and found the underlying cause of the problem. The connecter was nothing more than an interlocking set of thin rubber shields. One had a copper terminal with a banded of flat copper formed into a circle, with enough tension to hold onto the 2nd part of the connection. The other terminal was a round headed carriage bolt/screw where the threaded part of the carriage bolt (screw) was simply pushed into the other copper circular band. The problem was that the assembly of the carriage bolt/screw, wire, and rubber hood for the connector relied on a bared end of the ignition wire to be held into place, pushing onto the head of the carriage bolt/screw was secured by the rubber hood having enough elasticity to keep the wire pressed against the bolt head to make an electrical connection. In this case the wire was no firmly pressed onto the bolt head, it had slipped to one side of the bolt head and made intermittent connections and disconnection whenever the clutch cable was relaxed or under pressure, as that caused the clutch cable to move up or down - thus causing the cheap assed connector to open and close the primary ignition current feeding the coil. Frankly, that cheap connector assembly was a problem just waiting to happen.

Anyway, I did twist the wires together, and had both rubber connector hoods on the wire set in such a manner as to insulate the twisted wiring from touching metal anywhere. I took another victory blast up PCH, hitting 118 MPH at max again, then tore through Topanga Canyon back home. Once home I told my parents what I had found and that Dr. Lewis could come get his Capri any time that afternoon (I still hd to complete the wiring connection repair). One would have thought I was a Roman General coming home to a triumphant celebration following a hard ought campaign. My father could not be more proud of me, but he did tell me I could omit the part about driving up and down PCH at 118 MPH out of the story for Dr. Lewis. I think it was at that moment he felt that perhaps I might just be able to make a good living working on cars. The fact was I was dumb lucky. But, I also learned the value in listening to a customer carefully, asking some good questions, and to tug on wiring connectors when chasing down strange problems.

That was only the first of many time I found poor connections, fracturing wiring inside wiring insulation, bad grounds that cause all kinds of problems. And, my father lived long enough to see me become very successful as a technician, a manager in he computer industry, and finally when I founded and ran my own consultancy. Alas, at 91 he was laid to rest, and it was not until a few years later that I ended up selling our business and retiring (medically forced, brain cancer, 8 year survivor). But he lived long enough to see that I did just fine for myself despite not going into the medical profession. I think I had a lot more fun on the journey I took than I would have had as a physician, frankly. With my own very successful computer consultancy I know I did far better financially than any physician I ever met, many times over - and I am definitely having a blast now when I am able to share various diagnostic and repair techniques with fellow enthusiasts with these First Generation Mustangs and Shelbys, in forums like this and any number of Facebook Groups. Now retired I am doing exactly what I said I wanted to do in retirement "someday," play with my Mustang(s) all day...
 
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What good fortune on your part to have had such dumb ass luck! I have a similar story re: a 1973 Mercury Capri with a v-6 that belongs to a family friend and physician. He would drive along and suddenly the engine would die. He hd it at various Lincoln store (Los Angeles area) and Ford stores. The techs replaced everything, and I mean everything per the warranty copies, often the parts replaced had been swapped out more than once. Ignition coils, points, condenser, new spark plugs, distributor cap, rotors, carburetor, distributor, battery, alternator, ignition switch, fuses, fuel filters, fuel pump, fuel lines, even fuel tank, etc... This was definitely a "Hail Mary" shotgun repair effort made by the various dealerships, yet the problem persisted.

Well, my father (also a physician) really did not know to make of me, as I had by that time in life decided to go into auto repair for an occupation vs medical school. I had the chops to do medical school, but my interests were more akin to automobiles. He tried to put on a happy face for me, but I knew he was worried for me. Anyway, in an attempt to demonstrate his confidence in my ability in auto repair and braggingly told hie friend, "I bet Gilbert can fix it!"

So, there I was, given the Capri (5 speed manual, really nicely optioned) for as long as I needed, given $50 for gasoline, and told to ask for more if it was needed, and authorized to drive it as much as needed, to find the problem. And a "good luck" to boot. Me, in my first semester of junior college repair classes up against a problem the many technicians at several different dealerships had not been able to fix. And my father's reputation on the line. Yikes...

I ran it on an oscilloscope, everything looked good. The carburetor worked perfectly. The description of the problem screamed, "electrical." But everything was checking out, perfectly. Everything. But, I decided to persist. I had some advantages over what the various techs had. I knew what parts not to bother replacing because they had already been replaced, and I was not having to "beat the clock" in diagnosing and repairing the car. I could take my time, income generation was not an issue.

One early Saturday morning, on a day I was not scheduled to go into work, I decided to take the Capri out for a long drive down to Pacific Coast Highway and open it up to see how fast it was with the great running v-6. It was still early when I reached PCH, almost no traffic, and it was a nice almost bright morning with no rain or dew. I hit 118 MPH in one direction, turned around to do it again in the other direction. Funny thing, when I put the clutch in toe shift the tachometer went to 0, but when I released the clutch the tach provided a reading. I pulled into a parking lot and found I could suddenly replicate the problem. Clutch goes in, engine dies. Keep it in and I could crank the engine but it would not start and run. Clutch out and it started and ran perfectly, until I put in thee clutch again. I was able to replicate the phantom problem at will, a problem that had not manifested itself earlier all week long. I recognized this was a rare opportunity to locate the problem if my luck held out. With the engine running I popped the hood, and looked at the wires (I was now positive the problem was electrical.

I began to wriggle a few wires here and there, then I noticed a wire with a push-in connector laying on top of the clutch cable. As soon as I touched the wire the engine died! That was my first really big "Eureka!" moment in what would turn out to be a lot of such unusual problem resolutions over the next many years. I restarted the engine and repeated the moving of the wire, which lead to the ignition coil, time and again. I was convinced that was the cause of the problem. I pulled the cheaply assembled connector apart with the intention of twisting the end of the two wires connected together (away from any metal), and found the underlying cause of the problem. The connecter was nothing more than an interlocking set of thin rubber shields. One had a copper terminal with a banded of flat copper formed into a circle, with enough tension to hold onto the 2nd part of the connection. The other terminal was a round headed carriage bolt/screw where the threaded part of the carriage bolt (screw) was simply pushed into the other copper circular band. The problem was that the assembly of the carriage bolt/screw, wire, and rubber hood for the connector relied on a bared end of the ignition wire to be held into place, pushing onto the head of the carriage bolt/screw was secured by the rubber hood having enough elasticity to keep the wire pressed against the bolt head to make an electrical connection. In this case the wire was no firmly pressed onto the bolt head, it had slipped to one side of the bolt head and made intermittent connections and disconnection whenever the clutch cable was relaxed or under pressure, as that caused the clutch cable to move up or down - thus causing the cheap assed connector to open and close the primary ignition current feeding the coil. Frankly, that cheap connector assembly was a problem just waiting to happen.

Anyway, I did twist the wires together, and had both rubber connector hoods on the wire set in such a manner as to insulate the twisted wiring from touching metal anywhere. I took another victory blast up PCH, hitting 118 MPH at max again, then tore through Topanga Canyon back home. Once home I told my parents what I had found and that Dr. Lewis could come get his Capri any time that afternoon (I still hd to complete the wiring connection repair). One would have thought I was a Roman General coming home to a triumphant celebration following a hard ought campaign. My father could not be more proud of me, but he did tell me I could omit the part about driving up and down PCH at 118 MPH out of the story for Dr. Lewis. I think it was at that moment he felt that perhaps I might just be able to make a good living working on cars. The fact was I was dumb lucky. But, I also learned the value in listening to a customer carefully, asking some good questions, and to tug on wiring connectors when chasing down strange problems.

That was only the first of many time I found poor connections, fracturing wiring inside wiring insulation, bad grounds that cause all kinds of problems. And, my father lived long enough to see me become very successful as a technician, a manager in he computer industry, and finally when I founded and ran my own consultancy. Alas, at 91 he was laid to rest, and it was not until a few years later that I ended up selling our business and retiring (medically forced, brain cancer, 8 year survivor). But he lived long enough to see that I did just fine for myself despite not going into the medical profession. I think I had a lot more fun on the journey I took than I would have had as a physician, frankly. With my own very successful computer consultancy I know I did far better financially than any physician I ever met, many times over - and I am definitely having a blast now when I am able to share various diagnostic and repair techniques with fellow enthusiasts with these First Generation Mustangs and Shelbys, in forums like this and any number of Facebook Groups. Now retired I am doing exactly what I said I wanted to do in retirement "someday," play with my Mustang(s) all day...
Thanks for sharing that story, I had a similar situation with my father, who was a lawyer and a US Army Coronel. He expected me to do something much different than to go into business selling race car parts. I ended up doing very well and he eventually was very proud of me. Your story brought back a lot of memories, thanks.
 
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Sometimes it's just better to be lucky than good.
I have had a lot of good fortune. But none ought not overlook the persistence behind that good fortune. If did not just happen. Oh, the things I have learned when doggedly pursuing problems and solutions relentlessly.
 
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Well, I am thoroughly embarrassed at all the things that keep me off the road. Was heading out Saturday night, and I get a big old backfire then she idles like crap. Still have more of a shake than I like at idle, so I am afraid I have a vacuum leak or something.

Not sure why nothing works on this thing at all.

Kcmash
 
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Well, I am thoroughly embarrassed at all the things that keep me off the road. Was heading out Saturday night, and I get a big old backfire then she idles like crap. Still have more of a shake than I like at idle, so I am afraid I have a vacuum leak or something.

Not sure why nothing works on this thing at all.

Kcmash
What carb are you running?
 
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Holley 670 Ultra For the Carb.

I did some research and really feel the coil is my problem.
1) The failure is random, and electrical
2) Coils can show signs of:
a) loss of power/poor performance
b) intermittent misfires
c) random backfiring

My car has had some variable power when cruising along, not a consistent pull at steady throttle. It has random cutouts, especially when warm, and it has the random backfire issue through the exhaust. Fanning the throttle does not recover the power power loss as it bogs down, but does increase the exhaust backfire.

The coil I have on there is just an old Ford coil I had laying around. What do you suggest I buy?
kcmash
 
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The reason I was asking (the other day) what carburetor you are using is to determine if it has a Power Valve or not. The reason that is important is that a backfire, or even a mild engine burp-back, can create pressure in the intake manifold that gets pushed up into the vacuum chamber of a carburetor where the Power Valve is located (for carburetors with a Power Valve, not all carbs have them). When that happens it can damage the Power Valve diaphragm, which in turns allows the engine to suck liquid gasoline into the intake manifold, which then causes an excessively rich air/fuel ratio.

If you are using an Autolite 2100/2150 two barrel (2v) carburetor, or a Holley carburetor (2v or 4v) it is possible you are now having a Power Valve problem. But, for the Holley it can be complicated. If the Holley is a 1992 or later carburetor it already has a Power Valve Protection circuit in its design - which is supposed to eliminate Power Valve damage due to backfire/burp-back situations. For pre-1992 Holley carburetors Holley offers a Power Valve Protection kit that can be installed on an older 2300/4150/4160 carburetor in order to provide the same Power Valve protection built into 1992 and later Holleys. That kit part # is:



If you have a pre-1992 Holley or an Autolite 2100/2150 carb, it is very likely a backfire has damaged your Power Valve. The fix is easy enough re: replace the Power Valve. If you pull a spark plug and see a sooty black coating on the insulator you are burning a very rich air/fuel ratio. There are other ways to test to see if the Power Valve is leaking as well, but that is a sure fire way to see if the carb has been running too rich (other things can cause a rich mixture also, like a choke that is not fully opening once the engine had warmed up).

There are several pretty good YouTube videos showing how to replace the Power Valve in the Autolite 2100/2150 and Holley carburetors. I hope that helps...
 
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My Car
1971 Mach 1, Grabber Blue w/Argent stripes. Original 2V 351C Auto, Tilt, rear defog, Black Comfortweave Interior. Under restoration. Original colors, 4V 351C, 4-Speed, Spoilers, Magnums, Ram Air. All Ford parts.
Yep, mine is like a 5 year old Holley Street Avenger 670. I entry replaced the power valve and it made no real difference.

Based on the latest info I am pretty sure it is the ignition system. I am running standard points and and old Ford Coil. Gas problems may case a car to bog and die or run poorly, but rarely give excellent idle and throttle response, then fail for a second and idle perfect again, then randomly lose all power and die. Especially with new premium fuel and full float bowls.

I need an ignition guru to chime in now.
Kcmash
 
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