So in short, what you are saying is that as you have never experienced it doesn't/cannot happen?

And what does the factory ACL have to do with it if not operating correctly and most likely no heat riser?

It can't be much else as they have pointed the parts cannon at it on full automatic.

Quote:

Carburetor icing will usually occur when the ambient temperature ranges between 30° to 60°F,
when the relative humidity is above 65%, and when the wrong grade of fuel is used.

https://www.carburetor-parts.com/carburetor-icing.html

https://www.hemmings.com/stories/carburetor-icing/
Most likely the tank(s) is full of water from ethanol gasoline, no fuel treatment used and a defective EVAP SYSTEM.

 

I reread the original post. OP can you describe the “stall”? Gradual? Sudden? If gradual or sputter, agree that it’s likely fuel issue.

1. Put in some Heet additive. If it’s a little water, might work out. Easiest.

2. Install a fuel pressure gauge. Watch it at idle on a really cold morning.

3. Drain tanks. Hardest since you’re in an apartment. Maybe your garage can help.

 

The factory air cleaner isn't as likely to pull in snow kicked up on the hiway as some aftermarket crap or systems with a cold air intake. you don't need a heat riser, that's just to speed warm up and nothing else. when the air is very cold and most likely to cause icing the humidity is low. so no snow, no icing.

we used these pickups new on the ranch we pulled goosenecks all winter and NEVER had a problem. no problems running empty either . so am I saying it can't happen? pretty much. but I won't say it's impossible.

I'm saying icing is not the OP's problem because that's what this is about. mostly because it's not his problem. but ice in the tank would be.

 

I seriously don’t think that’s the problem either, and I have also never encountered it on a vehicle (not to say it doesn’t exist) but thought I would throw the info out there since the topic was mentioned.

Folks here are right though… It is likely something basic. If it were me, I would start by eliminating one system at a time. Fuel supply/storage is a fairly easy one. Get one of those cheap electric fuel pumps Edelbrock (or their Chinese front company makes), power it direct from the battery, and run some fuel line into a gas can that you secure in the bed. Attach the other end of the line with a filter on it to the carb and see how it starts and runs. Win or lose, you now eliminated (or identified) the tank, anything in the tank, fuel lines, and the fuel pump as the problem. Just a thought. Proceed at your own pace and/or caution.

 

Welcome, and good on you for keeping at it.

Keep in mind if the information fire hose is too much, you can always private message anybody here if it helps to keep it easier to work through.



Sorry to add to the dog pile of info but…; once your through all the above, a few things to keep in the back of your mind:

-check your grounds. On motorcycles, a decent number of electrical issues are related to poor ground connections. Also pays to check continuity with a multimeter through the block, frame, hood, etc. back to neg. terminal

-what kind of shape is the ignition switch in? How about the rest of the terminals between the batt and the ignition system? Have they had dielectric grease applied to keep moisture out?

-what kind of shape is your wiring harness in? How about the fusible links, fuse block, etc.?

-what state are the vacuum switches in, and what are they intended to control? (Most likely timing/advance dependent on coolant temp….couple that with fuel delivery issues, and a blast of cold air potentially throwing the AFR out of whack…)

-you’ve got a lot of new ignition parts; I’d be suspicious of anything/everything at this point. Are there testing procedures for these parts? Resistance or continuity readings on certain terminals?

-not that I’d put it high on my list, but having a “blanket” of insulation on the underside of the hood couldn’t hurt at this point if it’s that cold.

-I’m running 1/4 of a new aluminum 4-row radiator covered, 180* t-stat, with only 4 grill squares open; I’ve got the rest covered with a sheet of plastic. No problem idling in traffic at 60*F, and quicker warm ups with an open filter.

Looks weird but it works.

 

You know, it is very interesting as to how someone asks for help and the parts replacers all come out ...

If you had to do this as a living you would starve to death.

Well if that didn't work, lets replace this part ...

Why not just replace the complete engine and see how that does?

This period had mechanical emissions control. They were setup to run very lean. Any deviation from the calibration would give drive-ability problems.

Yes, the OEM ACL is needed (unless the engine was modified with a fatter fuel curve) but it has to function correctly as designed for cold weather. And why a carbed smog engine doesn't need a HEAT RISER SYSTEM for cold out side air, well I can't figure that one out either.

Maybe better to take it back to the shop where it was supposedly repaired and let them make a few more wild guesses costing how much?

SOURCE - https://www.carburetor-parts.com/carburetor-icing.html

It is not worth the fighting over it. The lady has her a$$ in wind until she finds a competent repair shop.

 

Carb icing is a thing, no argument. I've fought it a lot on snowmobiles back before fuel injection. and if you have icing you will have a throttle sticking, which the OP has not mentioned. it's just not a consideration in the OP's dilemma, or anyone else's with a 73-79 pickup and that's what we're talking about. before the heat stove people didn't have to park their car in the winter and use their horse and buggy I assure you.

The OP has ruled out nearly every possibility already. water or gunk in the fuel tank seems most likely to me. that is something I've seen happen .

 

It would be helpful to know if there is fuel or spark when the truck stops running. When it stop, take the lid off of the air cleaner, look down the carb. Work the throttle, do you see fuel squirting? If yes, problem is most likely not the fuel system. Carry a spark plug with you. When it dies, remove a spark plug wire, the engine end. Put your spare plug in the wire, set it on a metal surface where you can see it. Have someone briefly crank the engine over, look for spark at the plug.

I see some old rubber fuel line in the pic of the fuel selector valve, along with new. Could be a bad piece of old fuel line sucking air. With dual tanks, there is a lot more rubber line in the system, is it old or new?

I don't know the inner workings of the selector valve, but it may be worth bypassing it & running off of one tank to eliminate the possibility of it being bad.

If you suspect the ignition, start testing. Test the pickup coil in the distributor cold, then heat it with a hair dryer, then test it hot, see if the results change.

 

^This. Testing really needs to be done when the failure is actively happening. Intermittent stuff like this sucks but having the right tools and equipment with you when it happens will make life much easier and less expensive.

 

Hi and welcome to Ford truck enthusiasts. I read and see a lot of good information however not a lot of good ADVICE. I am a man in my 30s whom daily drives a 1979 f250. Now, you and I can not have tremendous and/or extensive long term experience with these particular vehicles, because we simply have not been alive long enough to obtain 25-35 years of experience with the fundamentals of the troubleshooting of these unique situations. I see recomendations to check pick up coil, while malfunction junction is in full stride. Good information, however HOW? The how is basically verify (check) for spark while the malfunctioning symptoms are taking place, If you have full good spark, then the pickup coil is likely negated as the problem, or the ignition module, or the coil or anything pertaining to the spark. How to check spark maybe carry a spark checker or carry a spark plug and a plug wire to check for consistent spark while hesitation to run is underway. Moving forward, on the assessment you do not have spark, now you can re post and hopefully we can help address the no spark symptoms. However, Also carry a small can/bottle of gasoline in the event you have spark, and no start and run. Dribble gasoline into carburetor after removing air cleaner cover and re try. If starts and dies, on dribble of gasoline, issue is almost certainly fuel related. Repost and we can hopefully start you on a new track (if you need the help) in order to mitigate the ongoing issue. good day.

 

Over the past couple of weeks I have spent some time when it’s warm out checking some things you all have mentioned. Here’s some of the things I found:

1. When my truck stalls while driving, it slightly sputters around 30mph. Then all of a sudden I lose all power. The engine cuts out and all electrical cuts out. The truck coasts and I pull it over to the side of the road. If I try to start it afterwards, I usually only have crank. I haven’t been able to check for spark when it dies on the road but I’ve been able to check for gas which it has.

2. I put a bottle of heat into each gas tank. Oddly enough, when I removed the rear gas cap, about a 1/4 gallon of gas came spewing out. I did crack the cap and wait for air to escape before pulling the lid. I’ve never had this happen before. Not even in the summer. I find it very strange that this would happen when it’s cold out. It was about 40 degrees that day.

3. The ignition coil plug/connector (not sure what you would call it) that goes to the wiring harness had moisture in it and is loose on the bottom side. I dried it off and put dialectic grease on it. I am planning to zip tie it on to prevent any movement. I checked the voltage across it and it gets 6 volts.

4. The negative battery cable was loose after I took it off. I had to reshape it in order to tighten it because it kept sliding off no matter how tight. I reshaped it and put dialectric grease around it. The small ground wire that comes off of that came disconnected. I had a hell of a time getting that reconnected. I will have to get another connector for it. It’s back together for now but I doubt it will stay for much longer

5. I checked for spark and I have spark. The spark plugs are black, carbon looking.

6. I turned the choke back a notch thinking it wasn’t getting enough air.

7. I put a new starter on my truck. The one I had was a cheap one from autozone. After trying to start it multiple times it cranks weakly. I checked the voltage of my battery and it has 12.6 volts. With the new Napa starter I have a much stronger crank. From my understanding a weak ignition system can also cause black spark plugs

8. I tried starting my truck on a warm almost 60 degree day and I could not get it to start. Ran out of light and left it for another day. Yesterday it was 40 degrees and it would not start. I removed the air cleaner and found gas all over the air cleaner lid. This makes sense as to why the spark plugs are black. I put a screw driver in the choke to hold it open. I tried to start it to see what would happen. I could see the gas spraying up as it tried to start.

So my question is, do I need to pull the carb off and rebuild it? What mechanism in the carb would cause this? Im guessing the float, but could there be other parts of the carb that would cause this? Is there any way to check without completely removing the carb?

As always, thank you so much for all the help and advice. I’m learning so much and slowly making progress.

 

Are you saying that fuel is spraying out of the carb vent when the engine is cranking? That and the general richness makes me think that the power valve is blown.

 

Good morning.
All of this sounds so familiar as I was having runnability issues with my Seldom-Driven Fords.
Don't just buy new plugs because they are black. Instead, use your propane torch to burn off the soot, then use a small wire brush to clean them up. I like the small wooden handled wire brushes with stainless bristles sold at the welding shops.
Sooty plugs means too-rich (over-fueling or over-choked).
If you have fuel shooting up from the carb, your fuel float needle is not seating properly.


It looks like you have a 2-bbl motorcraft. When the engine stalls and you roll to a stop, simply unscrew the top cover, lift it up far enough to see if the float bowl is empty. If empty, you are lacking fuel supply. If full, the problem is else-where, _ _ maybe electrical failure.

Holleys are notorious for the O-ring failing that seals the Needle-seat assembly to the carb body.
The ethanol fuels seem to also Petrify the poly tip of the needle thus no sealing either.

What happens is that running down the highway the engine can keep up with the fuel leakage, but once the engine slows down like at idle, the carb is overwhelmed with Too-Much-Fuel causing stalling and BLACK plugs.
Seems I am constantly fighting this with my Ford fleet, and it doesn't matter if it is the 300-six or my 429-V8.

Steve, a mech over on the "aboristsite.com", says anymore, before he begins Troubleshooting a newer vehicle, he checks all known grounds for proper continuity. That makes sense.

So, your situation is a tough one because the issue is sporatic.
Is the engine lacking fuel when driving down the road and it stalls ? _ _ hmm, the black plugs tells me it has fuel.
Once plugs are black and fouled, the engine will be difficult to start back up until the engine sits and fuel evaporates off the plugs.

Ford Dura-Spark ignition boxes leave you stalled when they start to go BAD. _ _ _ I've had a Napa account for 40-years.
I love patronizing Napa, but _ _ _ I won't buy their Dura-Spark boxes _ _ _ only use MotorCraft if available.

Here is another thought:
If you do have an electrical issue causing stalling while driving down the road, and you crank the engine to Restart, if there is no spark, the plugs will get fouled, resulting in more difficulty for the engine to Fire-up.

I know, I haven't answered any problems, but I used a Napa dura-spark box with warranty. I was left stranded in the middle of a busy downtown intersection, and was very embarassing, pushing the vehicle over the curb.
I took that trusty Napa ignition module in to the Napa Store, and guess what ? _ _ they had a Dura-Spark tester machine.
The salesman plugged the box into their "magic-machine" and the Green Light popped on. The salesman, said SORRY, your module is OK, because the green light is on. Hmm, I was set-up, and have never ever purchased another ignition module from Napa since, and that's been 35-years. I was soured. Bad-*** Warranty promise for selling a part.
I turned around and drove to the Ford Dealer and purchased a Motorcraft Dura-Spark, and that solved the Stalling.

I wish you best of luck putting a finger on the PROBLEM you are encountering.
Just a thought here - (another thought). If affordable, you might consider taking your pickup to an Auto Electric Shop, and have them do some diagnostics.
My dad worked in the automotive industry his career, and one of his respected associates always said that 85% of runnability issues are ELECTRICAL.

I am commenting from Sunny California where we seldom see temps below 28* F.

 

Greaser007 touched on the ethanol fuel issue. If at all possible....Avoid it! That ***** is horrible for older vehicles unless you drive it regularly. I haven't burned it in my truck for over ten years and I've had zero issues with fuel delivery. I'm also not running a Holley or a Motorcraft carb on my 460. Some folks don't like Edelbrocks but Im the type that doesn't want to mess with a good thing . Only issue I had was the carb flooding at low rpms because of the fuel pump pressure. Once I got the FPR setup and dialed in at 6psi all was beautiful. Just my thoughts and .02

 

A lot to unpack. I’ll try to be concise and brief and sorry if I missed something from earlier. {Synopsis; is oil getting into the cylinders and complicating combustion; and do you have a rich condition already with a carb setting issue fouling plugs; or is something else the cause of flooding while driving?}

-Question: how many miles are on the motor?

-Question: have you or anyone else tried looking in any cylinders for carbon buildup? Oil?

-Question: How much oil are you having to put in it between oil changes? With what frequency?

-Question: Do you know what the current carb settings and jets are? -Follow up; Do you or mechanic know the function/settings of all the different carb circuits and if they’re clean?

-Question: When the mechanic re-jetted, do you know if they used a sniffer (O2 sensor), or pulled plugs and checked color?

-Question: Has anyone checked the exhaust manifolds for leaks at the heads or collectors?

-Question: When you’ve been stranded, have you pulled plugs? What did you find? If you cleaned them, did it fire back up?

Im curious of a few things you’ve got going on, all of which I’ve had troubles with before.
My old F100 360FE had oil leaking into the cylinders from the valve stem seals in the heads, and would foul plugs, but would sometimes re-start without cleaning. {Wondering what kinda of shape are your rings and seals in? }

My current FE “leaks” oil in typical ford fashion, but also consumes a little on hard deceleration (above 3k). Before I got the valve cover baffles and venting sorted, it was sucking a little oil into the intake regularly.
{How is your evac system routed, what condition is it in, and is there a problem with it?}

I’ve also run into issues with leaking valve cover gaskets that allow oil to settle into the spark plug valleys(?) and slowly seep past the threads into the cylinders. My current FE took a lot of persuading to finally get the spark plugs tight enough so that leakage (out and in) was no longer a thing. Shoulda sprung for new heads.
{Do you have oil getting into the cylinders from somewhere unexpected?}

Also sounds like a bad tune on the carb, or worse. You may also have a major rich condition already, cause I don’t how you’d be able to drive in sub-freezing temps, and then 60* plus without the tune being a bit off. That coupled with a poorly adjusted cruise circuit and faulty power valve, equals flooding and fouled plugs in my book. If you also are having electrical system issues coupled with weak ignition and a little oil in the cylinders, all seems like a recipe for expletives and loads of head scratching (been there).

So much for being brief.