Electrical or fuel problem?

[wanahemi]

I got some unexpected gremlins that came with my recently purchased car. I bought a 68' 340 GTS Dart. (automatic) The engine has been converted to electronic ignition (4-pin module),Accel coil (stk. size one), stock electronic distributor, 2-pin resistor (changed) and mechanical fuel pump. The charging system is still the old electro-magnetic voltage regulator (changed). Edelbrock intake with a weird Edelbrock with Weber on the side carburetor. It has the electric choke hooked up with, I guess some sensor to raise the idle when the A/C is turned on.
The car runs fine for the first hour or so. After that, the idle starts to get bad, then sputter, sometimes backfire through the exhaust, then dies. Sometimes it will start right back up and does the same thing. Other times, it does not want to start up at all. Engine cranks, but no firing up. I thought it might be the module or bad ground on the module. But changing to a spare module and adding a groud wire did not change anything. Fuel pump maybe? The engine temp. is fine, never gets over 190. But this engine dying thing only happens when the engine has been running for awhile. Any ideas?

 

[cuda67bnl]

clogged fuel filter, maybe.

 

[moparsegura]

I've had similar problems before. Next time it does it be ready to check for spark at the #1 plug, if it fires then go to fuel. But it does sound like a fuel problem to me. I had to go through me Holley last time I had a same kinda problem. Just had junk in there that needed cleaned out.

 

[OldVart]

Coil overheating?

 

[Thrashard340]

nvm...not a choke issue like I originally thought.

 

[ramcharger]

Sounds like it may be vapor lock. Next time it happens if the engine doesn't start, pull the air cleaner and wack open the throttle. If you get a nice steady stream of gas from the accelerator pump, it's not a fuel problem.

 

[orgvcregal]

i had the same problem it was a faulty coil when it got hot it just cut out.

 

[wanahemi]

Thanks for all of the advice. I will try them out. Wish me luck!

 

[wanahemi]

Thanks for all of the advice. I will try them out. Wish me luck!

 

[Dart-swinger]

I had a very similar problem with my 340 dart years ago.It wound up being the electronic control box.I was running the mopar orange boxes and didn't know that they were only good for 5500rpm and I had been hitting around 6500 .I changed to the mopar performance chrome box and have never had any problem since.And that was around 15 years ago8)

 

[shhnappa]

Thanks for all of the advice. I will try them out. Wish me luck!

Resurrecting an old thread here, but for good reason. :-D I have the IDENTICAL problem, with the same motor, and I'm leaning towards fuel boiling, what did you find that corrected the problem?

 

[wanahemi]

I found out the previous guy who worked on the car overtightened the crap out of the plastic fuel filter. To the point, the element inside broke loose and was floating around in the plastic housing. After changing the filter, saw that the fuel pump did not maintain a steady fuel flow to the filter. After changing the pump, 'knock on wood', car is running fine now.:-D

 

[3404spdvaliant]

I had a 74 dart 318 that did the same thing and it was lots of crap in the tank clogging the filter and carb.