So I just bought my '79. Got it home took it for a drive with the wife got it home again. Went to start it the next day fuel pump is shot. I got a new fuel pump in and she fires right up no issues. As soon as I leave the start position car dies. As soon as the car leaves the start position everytime car instantly dies. I know how to drive and start up a carburated engine it's not my first rodeo. But as soon as I get it started give it fuel while in the start position it runs but as soon as I let off the start position it instantly dies. Wtf? Any thoughts?

 

Somethings wrong with the ignition switch. Check to see if the fuel pump is running with switch in the ON position. You can also check for 12v at the fuel pump with switch on.

Factory Service Manuals and wiring diagrams can be found here: https://foxed.ca//index.php?page=rx7manual#firstgen

 

Mine did that also a few years back. My issue was with all the vacuum hoses going and leaving the carburetor back to the spider cluster.

 

Yours would only run with key in the START position because of the vacuum lines?

 

Pull the plugs, red insulator points to gas starvation.

And you should be able to hear the fuel pump with the ignition key in running position and engine off.

Also , something similar to what you describe was solved by replacing the fuel filter.

 

If this is a new-to-you RX7, and esp if previous owner had it sitting, you DEF want to swap in a new Fuel Filter!!!!!
Cheep ($4) at any auto parts store. Located behind rear driver wheel underneath. Solves all sorts of running probs...

Stu A
80GS
AZ

 

This could also be that the coils are losing 12v after starting.

 

So I swapped out a fuse for another fuse and it fired right up. Today I changed the coils and now it seems like it runs rough. What could of happend?

 

Have you tested fuel volume according to the Factory Service Manual?

 

It would start and running fine as long as it was sitting idle. Once I tried to drive it. The car would just stall.

 

Don't we all wish GSLSEforme could weigh in on this one? If you have the original coils, PUT THEM BACK, he would say. A failing ignition switch seems to be the likely suspect here.

 

Completely different issue. OP'ers car is stopping after letting go of the ignition switch when starting.