...and 20 minutes later, she dies.

[my69rt]

For the last six weeks I've been using the Charger ('69 w/440, .030 bore, mild cam, edlebrock 750 carb, MP electronic ingnition conversion kit) as a daily driver and the car has been running very well.  It starts easy and runs great on the first start of the day and pretty much every other time it's sat for 2-3 hours or more.  If I'm only making a quick stop and it's been shut down for anything less that 2 hours it is a hard start, have to crank it 10-20 seconds and give it full throttle to get it started.   

Over the last four to five days after about 20 minutes of driving the car starts to sputter and lose power.  As soon as I let of the gas the engine will quit and not start again until after about a 2-3 hour rest....then 20 min later she dies again.  This is most troublesome when it happens at a red light and I have to push it out of the intersection (twice this week).  On drives less than 10 minutes after shutdown there is usually cough and sputter.  Any suggestions on where to start looking?

Thanks,

spence

[1BAD68]

Start with basic tune up stuff.
I have a 1965-1972 Chilton's that I got from my Dad and it has helped me through problems like that.
If you can find one somewhere, its well worth it. Walks you through the diagnosing and repair of everything on these old cars.

[maxwellwedge]

Fuel heat/boiling, tank vent, clogged filter, one of the defective vapor seps (if you have one installed) smegma in the carb, wiring heating up near the engine/exhaust.....check that stuff out first

[b5blue]

Is your intake aluminum? If so it needs the heat ports blocked. If factory setup is the heat flapper on the passengers side exhaust manifold working correctly? (If its stuck closed it forces too much heat into the intake's crossover.)  

[Chryco Psycho]

I agree
install a Fel Pro 1215 intake pan under the intake to block the heat crossover , unless you drive this car well below freezing having it open helps nothing

[kedso]

Don't forget to check the electronic ignition.  I had trouble with mine after about 20 minutes of running.  I noticed potting compound leaking down the fire wall.  Changed the box and all was well.

[richRTSE]

Don't forget to check the electronic ignition.  I had trouble with mine after about 20 minutes of running.  I noticed potting compound leaking down the fire wall.  Changed the box and all was well.

After going through several mopar orange boxes, I switched over to MSD years ago.

[A383Wing]

fuel pump push rod issue? Worn out?

[crusty440]

I had the same problem with my 69 -440, fuel pump push rod worn

[my69rt]

All- appreciate the input, will work on it over the next several days and post how it goes.  I Recently moved to Hawaii and the temps here are pretty steady with a high of 85 daily - cold weather is not an issue. 

The intake is stock and I've no idea what the heat flapper is...will look into that one.  I'm first going to replace the fuel pump/filter and look into heat build up...though the car is running the coolest it ever has out here (I installed a Miloden HV pump prior to the move).   If the fuel pump doesnt' fix it maybe I can use this as an excuse to get an MSD ingnition setup....I need some reason to fool the wife into letting me spend money on the car!

thanks.

   

[flyinlow]

Check that your choke is opening properly, 5-10 mins. to open.

Check the heat riser valve is free and operating normally, or install the Felpro 1215 valley pan/ gasket as mentioned to block the heat crossover.

An insulator under the carb can help.

Try a different brand of gas. Today's fuel is blended for injected engines and causes heat/boiling problems with our carbed engines.

[W4ATL]

Your coil may be failing. Replace it. Doesn't cost much.

[chargd72]

Your coil may be failing. Replace it. Doesn't cost much.

How many volts is your coil rated at?  Is it making any sputtering noise when it dies?  I put a high perfomance coil on and it did the same thing.  It got scalding hot too.  Put the original back on and no more problems.

[Schlabuster]

Had sometimes the same Problems, after some Miles driving the car wont start. When i am searching about the reason of the problem i found that no gas is coming from the tank. So i put out the sending unit, clean it an change the filter, replaced the pump and blow the fuel line from both sides through. When i filled the tank up it takes very long time to start the engine, when i take a fuelcan stick a hose in it and connect it with the new pump the engine starts in seconds
Could it be that something block my fuel line and it is not impossible to blow it out?

[six-tee-nine]

Old tank?

If so, maybe it contains alot of goop/rust pellets that get stuck in front of the suction hole when you get driving. After a stop all the debris sinks slowly to the bottom and you can get going again until is swirls all ove the tank again.
Cant tell if this is a problem of old mopars but have seen it a zillion times on several brand X vintage cars

[Schlabuster]

Oh i forgot to tell that i had the tank removed and inspected. The tank is inside like new, it was very surprising to me to see this. The push rod must be ok because with a fuel can the pump is working.
mysterious 

[67tbird]

Maybe fuel pump is just strong enough to pull fuel from can, not from tank might want to check push rod like earlier posts stated.

[70 Charger RT]

If your car was originally a 318 or 383 car, it came with a 5/16" fuel line from the tank to the pump from the factory.  In 440 / 426 cars from the factory, the fuel line was 3/8".  Check to make sure your fuel line is at least 3/8".  I'm not saying that is the problem, but it could be contributing.

[my69rt]

All- Thanks for the input.  Sadly my dumb self tried to drive it "one last time" to work before trying to fix it...it died half-way and was not coming back to life after a rest.  Had to get it towed and the rattiest looking Tow-Mater look alike came to pick me up, most tragic... Swapped out the Electronic Control Unit and Coil (I don't know which was the problem) and am back on the road. Big Win.