Technical Engine Won't stay on.

My '63 F100 has a "78 Ford mostly stock 302. It was running like always, like a champ. Friday after work I noticed it was running at a lower idle than usual, and barely staying on. I got it home by keeping my foot on the accelerator at all the stops. It has headers and an aftermarket HEI, chevy type distributor.

I have fuel to the carburetor, I can see gas in the clear fuel filter, the reservoir is full, and I can see gas spraying in the carburetor. I checked to see if the spark plugs were fouled, they were all ok, I cleaned them anyway. I seem to have spark, since it runs while I'm on the accelerator. After starting it, I had someone disconnect the battery, while keeping my foot on the gas, to check if it was the charging system. HEI is less than a year old.

What's next?
Thanks in advance, fellas.

 

Check for vacuum leaks.

 

Yep,
Cracked hose, loose hose.

Whatever it is should be pretty obvious.

 

I'm sure that is more than just a visual inspection, can you elaborate? Can I do it by myself, or do I need an extra person?

 

A condition where "it ran fine then all of a sudden didn't" is usually really easy to find. Something usually broke, fell off, came loose, or plugged up.

Without more information its hard to point you in the right direction but what you describe is pretty much the classic vacuum leak.

 

I checked every vacuum line leading to the carburetor, none are cracked or torn. Checked pcv valve and it seems to be in working order. Anything I'm missing?

 

Try spraying a little starting fluid at the carb base gasket, any vacuum lines etc. If the idle speed changes
you have found a leak. Otherwise I would suspect that you got something in the carb passages.

 

Carburetor base gasket

Intake manifold gaskets

Vacuum fittings to the intake and carb

Anything that operates on manifold vacuum: brake booster, distributor vacuum advance, vacuum modulator, windshield wiper motor, HVAC controls and actuators, vacuum reservoir tanks, Hollywood Wolf Whistle horns, etc.

 

does this have dual exh or single I had a exhaust pipe on 71 monte carlo one time that the inside of the of the exhaust pipe collapsed and I couldn't get over 20mph was in tuckerman ar stopped at little dirt floor garage and paid the guy 5 bucks to cut a hole in to get me home. just a thought.Tom

 

Take a look at the cap and rotor. And inspect your plug wires. Might have melted a wire near those headers.

 

Make sure the distributor isn't loose and the timing hasn't slipped - try twisting it.

Next I would take the carb apart and clean it - sounds like a clogged idle circuit could be the culprit

 

Its probably a vacume leak like the guys said. Just wanted to add I have bought aftermarket new chevy distributers in the past that were junk especially the moguls from local parts stores

 

If it has the stock ford exhaust Y pipe they were often double wall pipe and occasionally the "inner" pipe collapses and causes high back pressure ....wich causes low manifold vacuum....Now I see studebaker 46 had the same idea!

 

I know u said u got gas, but enough ? Check for clogged gas filter, weak gas pump ?

 

HOTRODDON: X2--- Dirt in idle circuit

 

Cleaned out the carb and replaced HEI module. Idles great, it ran well, then, it shut off and ran like crap after restarted. Obviously, very frustrated.

 

Limped home. Replaced all vacuum lines. Same result.

 

What did you do to it between.
Ran shitty then its running great.

Now its running shitty again?

 

Timing chain.

 

after reading all the responses I would say it is either fuel or electrical.

...unless it is something else.

 

Lmao

 

When chasing a problem, it is better to make only one change at a time so that one can accurately evaluate the results. When you change two or more at the same time, how do you know which fixed it? Or, which failed when the problem returns.

Ray.

 

That's an excellent way of destroying your alternator.

 

A 1978 302 would have had some smog equipment on it. What happened to all of it?

 

Holley carb with a blown power valve?

 

It's fixed. Unfortunately, I don't know what the issue was. I just started all over again with the old module, removed all the vacuum lines, and reinstalled them. Of course with the new hoses. I wish I could pin point the issue so it can help someone in the future, but today I'll settle for "it runs like before it broke."

 

Motorcraft carb. Most smog crap is still on it. I want to eliminate it all but, maybe as a future project.

 

4 hours ago it was fixed and then broke again. But now its fixed again.
I hope you won't need it but don't leave without your phone.

 

This is FUNNY!!!

 

LOL first thing I would do is stick my screw driver in that little screw that controls the idle speed and give it a twist.