i have a 91 Civic with a swaped in Zc sohc that was runnin but now it wont.
Ok, now the car wont stay running, last week it had 2 huge back fires and started running like crap.
Now when i start it its fine and revs ok for a min then dies, restarts and runs for less time, then restarts and then runs for even less time. this has gone on for the last 2 nights. the longer the car sits the longer it runs up to about a min.
Main relay maybe? or somthing in the dizzy.
When we try and try to the point where it will not start we pull a plug and there is no spark. and the plug is dry ( i would think it should be wet from flooding)?
Is there something that could go that controls spark and the injectors not to work and then work when cooled?
Im so lost here.

 

Main relay 'could' do that, but more than likely it's something in your distributor or a bad ground.

When it won't start, turn the key to 'ON' and listen for your fuel pump.
If it whiirrrrs then most likely your main relay isn't the issue.

Check all the grounds.
Take the grounds off and clean up the the metal... make sure they are good.

If that all fails troubleshoot the distributor.

 

Thank you 4DrEF. for the detailed response. You really seem to know your stuff. I headed up the hill tonight with a Dizzy and a main relay planning to switch them out. I started the car and went to shake the main harness and car stalled. and i seen a spark. 2 wires the were grounded to the therm. housing were loose. tightened and the car runs. Still having issues with the car but its in another thread. called "willing to pay if problem solved".