Not starting when warmed up

[tickerwilson]

Hi, I have a 1970 dodge dart swinger with a 1987 318 in it. When cold it starts up right away and I can drive it for an hour and turn it off. It will restart right a way. But if I let it sit for a half hour it won't start. I have to wait an hour or so and it will start. I have replaced the coil and resistor. Any help would be great.

 

[MadScientistMat]

By not starting, does it crank and crank but not fire, or does the starter do absolutely nothing or just click?

If the starter turns, do you have spark when this happens?

Does it use a points or electronic ignition? If it's a non factory ignition, what mods?

 

[MOPAROFFICIAL]

Might be the heat..and carb trickling fuel down the intake, flooding it.

Put the pedal to floor next start up.

 

[tickerwilson]

By not starting, does it crank and crank but not fire, or does the starter do absolutely nothing or just click?

If the starter turns, do you have spark when this happens?

Does it use a points or electronic ignition? If it's a non factory ignition, what mods?

Hi, it cranks but won't fire. Points, factory ignition. No mods.

 

[tickerwilson]

Might be the heat..and carb trickling fuel down the intake, flooding it.

Put the pedal to floor next start up.

Hi, I tried the pedal to the floor. When it cools down it starts up. Ignition module?

 

[MOPAROFFICIAL]

Hi, I tried the pedal to the floor. When it cools down it starts up. Ignition module?

You can turn the key to Run and test for voltage across the ballast. Ballast powers the coil....then narrow it down from there. I've never had a module get hot and stop working but it doesn't mean it's not possible.

 

[tickerwilson]

You can turn the key to Run and test for voltage across the ballast. Ballast powers the coil....then narrow it down from there. I've never had a module get hot and stop working but it doesn't mean it's not possible.

Thanks for the reply. Will look more into it tomorrow.

 

[AJ/FormS]

what carb is on the lo-compression engine?
What do you have the Idle-Timing set at?
My guess is the transfer slots are too far closed,
and/or the fuel level is too low.

 

[Oldmanmopar]

A moderator can find you the post for this picture. Fixed many with this same issue.

 

[Bewy]

Post #4 you mention points. Then post #5 ign module?

 

[67Dart273]

I would guess fuel, boiling, vapor lok, etc

But check your CRANKING spark. "Rig" a test gap using METAL CORE wire, not the factory radio supporessed wire, to the coil tower. Either get it so you can see it AKA through the hood gap, or get a helper, and crank it USING THE KEY---do NOT test when jumpering the starter relay, as this changes the circuit. Spark should be hot, blu, snappy, and at least 3/8 and more typically 1/2" long

Test cranking coil voltage. "Rig" your meter to coil + and ground. With key in "run" voltage will be various, anywhere from 6-8 or maybe 10. If it is battery voltage, the points are open, bump the engine. The points must be closed to get current through the coil.

Next, read the meter while cranking the engine, again with the key. This voltage should be very close to battery cranking V. That is, if the battery pulls down to 11V cranking, then coil + should be very close to that when cranking.

If that checks out, make sure coil wire is not burned --check continuity, check rotor and cap internally for condition, plug wires, and plugs condition.

THEN GO concentrate on fuel problems

 

[67Dart273]

Modern partially alky fuel sucks. It boils much easier than "old time" gas. I improved mine with a DIY vapor return system that OldManMopar posted above, I converted to a rear mount electric pump (pushing) and a carb insulator gasket.

There are several Wix filter numbers, in 3/8 and 5/16 tube, that have a 1/4" return orifice tube. You must devise a way for a return tube into the tank.