I really need some help. I've owned this 1978 coupe for a little more than 3 years now (not my 1st II). This has been an issue from day one...and I am really needing to use her for a daily driver now.
I am not real "techy", but have some basic knowledge... so be gentle
Once I drive the car around and reach a normal operating temp., the car does not want to start again. (I have gotten stranded several times) It cranks weakly, and does not want to turn over. The only way I seem to get it going is pumping the gas while cranking, and if I don't keep the RPMs up over 2k, it will die, and I get to start all over again. The timing has been checked and adjusted, and that did not have any effect on this problem. It has been suggested that it might be the coil, I am somewhat suspect of the carb... it wants to idle high when out of gear after it warms up too, but idles fine after initial warmup, bumps right down to 700... but after I drive awhile and take it outta gear it idles around 1200.
Any ideas? I've thrown a ton of money into this lil pony, and I am in dire need of paint right now too.
Thanks!!

 

No one even has a suggestion... seriously?

 

Not too many people check out the Mustang II section and I was waiting for an expert to respond but I will give it a try.

I think that your gas is vaporizing either in the gas line or the carburetor bowls. After stopping the car hot, the residual gas in the lines will turn to vapor and not be able to be atomized into something burnable in the cylinders. Likewise, heat can (will) rise up from the manifold and get your carb hot as well. The fuel stored in the front and back (or side if an Edlebrock) bowls can turn to vapor as well. You can also have a bad gas cap. It should have a one way valve to relieve pressure from the fuel pump sucking gas out through the bottom of the tank.

Fixes: Reroute your fuel line away from as much motor as possible. Make it as short as possible too. Also, wrap it in some heat reflective wrap or get a nice braded one from Pep Boys. Check your fuel pump, make sure that it's not too aged. It should be pushing 6psi. Get a carb spacer and look at how big your air cleaner is. A big air cleaner can trap hot air between the manifold and the carb bowls. Typically it's not a big deal if all of your other stuff is working. Wrap your headers to keep under hood heat down a bit. All cheap fixes, do those and see what it does for you. Timing and fuel pump issues would show themselves on a cold motor as well, so you can rule them out for the time being. If the other stuff doesn't work then take a look at your timing and pump.

Hot motors are just a little bit harder to start. I think that hot pistons expand just a little bit which close up the gaps and make the motor a bit harder to turn over, again, I wish an expert responded. I've just worked through every issue in the world with my Mustang over the past 5 years. I hope this helps.

My first car, fyi, was a pimp blue with white strips 76 Cobra II. I loved that car....

Welcome to the forums btw.

James

 

Oh and as for the carb not going back to idle, check your linage. Squirt some liquid wrench or something on the linkage parts to make them unbind.

 

Thank you very very much for the response I will see what I can get done and if it helps. I thought vapor lock myself, but when removing the gas cap didnt help, I kinda blew that idea off... I will revisit that. Thanks!

 

Try advancing Timing a couple Degree's.

 

dude- you answered a post that is 5 years old... SMDH

 

I'm sorry, I'm old and creped! I guess I should change the glass's. Dude is West Coast, We are Bo's here in the Southeast.