Need some help, have just installed a Mazda factory rebuilt long block in an '86 non turbo. Fires up right away and runs about 5 second or so and quits. On a restart the engine starts right up and quits. Have shorted the injection pump test lead by the air flow sensor, the engine starts and runs fine.....
I'm certain that there is some simple thing I have overlooked....

thanks in advance

 

You might try disconnecting the exhaust system. It is possible that cat might be plugged.

 

Mine did that when I had the timing completely bassackwards. Doublecheck your CAS setting.. Backfired like a cannon too

PaulC

 

Check Timming... Check the injector plugs...Check for vacumm leaks...