Hot car won't start until cooled down

[TripleT]

Sorry for the noobish  question here, but my car (340 with Eddy 4bbl) has a super hard time starting after it's been run.  It makes going out for a quick burger or errand not too fun.  I assume the gas is vaporizing (or something) as it's too hot  and that is somehow keeping it from getting a good mixture to fire on....

Another SUPER noob question, my car (70 Cuda) has a manual choke.  I use it, and as soon as it starts I push it back and the idle smooths out.  Should I be giving it much gas when I do a cold start?  I'm not sure if it's better to depress the pedal all the way, pump it, or what.  and what about when it's hot?  I don't use the choke obviously, but I'm still not sure how to properly use the gas pedal to get the fastest start.  Electronic by the way...

Thanks, and thanks you guys never make me embarrassed for being a desk jockey my whole life....

[Bullitt-]

Before you do anything to the car I'd check that you are getting spark when HOT...many electric gremlins appear with heat...

Having grown up with carbureted engines I's say you need to pump the pedal at least once, maybe more, even with a warm engine just to get a squirt of fuel in the intake..
When cold my experience is 2-3 pumps on a properly operating engine, the choke & fast idle cam take care of the rest

As for the manual choke I would not push it all the way in, just part way, until the motor warms up a little...once underway push all the way in.

 

[JayBee]

...many electric gremlins appear with heat...

Ages ago when I installed a new Mopar electronic ignition my car had a hard time starting when hot too, sometimes it didn't at all until a good cool down period. This happened shortly after the unit was put in and I never suspected it being bad because it was fairly new. After trying some things I finally broke down and bought another orange box and never looked back. I'm not saying this is your problem, just passing on an experience of mine...Good luck   

[Chryco Psycho]

 
you may be losing spark with heat or the fuel could be boiling in the carb & flooding it so you may need to hold the throttle open when starting it hot
 it is hit & miss whan cold , different carbs supply different amounts of fuel so you may need 1/2 pump -2-3 pumps to get it to start properly , you will have to learn what works best for your car

[71chally416]

If you're talking about having trouble starting a warm motor I wouldn't blame the carb unless the motor is really hotter than normal. It's probably your ignition box. Before I installed the MSD on mine the old orange box would start the car immediately when it was cold, but was always a pain to start when it was hot. Don't know why. Now it always starts the same. Same carb, different ignition.

[72bluNblu]

 

Does is have the regular points/condenser type distributor or the electronic version? I had a bad condenser do the exact same thing to me, car would start up and run great right up until you'd been driving it about 20 minutes, then it would die and not start until it was cold again. Could also be the ignition box on these Mopars. I'd check that first. It could also be a carb problem, if its running rich it will start and run great until it heats up, rich enough and it'll die and not start again until cold. And check the routing of the fuel line, if its touching the engine/manifolds anywhere you could be vapor locking. But if its doing that at normal operating temperature its unlikely you've got fuel vaporization unless something is routed wrong.

Also, with the condenser or ignition module it can be difficult to test for the problem, more often than not these parts will test fine while cold, you actually have to heat them up to get a bad result out of them.

[dodge freak 2]

My guess is when hot a bit fuel is dripping out of the carb booster...I seen my Holley-Demon carb do it...I run the intake exhaust heat year round so in the summer it gets pretty darn hot.

That said it will start but after 10-20 seconds of cranking sometimes (mostly while park in a garage for about 20-30 mins). Other than those times it starts fast.

But it has a mini MP Mopar starter that cranks the motor over faster than a big old stock starter (they make even better ones but are up to $400 depending on brands).

Has great plug wires and every year gets new spark plugs just cause its a new year, lol. Really plug wires should be change every two years or so...might be over kill but misfires and worst yet-no starts aren't fun.

You might try just cracking the throttle open like a 1/4 way if it doesn't start the first few seconds..that is what I do and just keep on cranking til it fires. (I have a DP carb so flooring it would put much more fuel in what is the last thing it wants)

[TripleT]

Thank you gents for the good responses, many variables here and I will be experimenting, for now it definately starts cold better than when it's hot!  Thanks again.

[BruteForce]

One thing worth checking when the engine is hot is that it hasn't overheated.

[Chryco Psycho]

yuo may need to block the heat crossover passage in the intake if it is boiling fuel in the carb
 Hot start I always try to start it without touching the throttle first then slowly open the throttle while cranking if it doesn`t start right away
 there are lots of possible problems , , if the choke comes on while hot the choke is not set right , it should only lightly close at 70 * F when cold
 your float level could be too high or low
find out if fuel is boiling over & flooding the car while sitting ,
 Timing could be too retarded , mixtures could be set too rich or lean