Well, I have a 1990 Honda Civic 1.5L. I bought it with a blown head gasket. Rebuilt the motor, put new rings, gasket, head decked, bearings....etc. When I go to fire it up, it seems to run a little rough at idle then a couple seconds later it will instantly start running fine. Sometimes if I leave it for a while, I have to hold my foot down on the gas and crank it over until the battery is almost dead before it sputters then comes to live... stumbles at idle, then instantly runs fine. There's no smoke coming out of the tail pipe when it finally fires up either, so I would assume that rules out head gasket or flooding.... right?? So I thought it may be a fuel filter issue, or air starvation, so I replaced the air filter and the fuel filter, but seems to do the same thing... Then I thought maybe it could be a bad ground between the block and the battery, so I made new grounding cables.... nope, not that either. So could it be something in the timing??? Because the idling feels like its almost missing a cylinder or poorly timed, then in a matter of maybe 3-10 seconds it instantly starts running fine.... Help??

 

When the engine won't start, check whether you do or don't have bright spark at each of the plugs. If spark is fine, turn the key to ON without cranking the engine and listen for the low humming noise of the fuel pump priming for a few seconds. If you don't hear the fuel pump, then you may have a faulty main relay.

 

If ya have fuel and spark, check outthe valve clearance... mine had been doin the same then it got worse spent a bunch of money on stuff i didnt need and then i checked the valve clearance earlier, adjusted it and walla runs great and starts easy...

 

How do you think the valve clearance got so far out of adjustment? That must be a pretty rare cause of a no-start problem.

 

I thought about that, but I hear the relay click 2 seconds after the check engine light goes out.

 

Do you also hear the 2-second humming noise of the fuel pump?

 

Old gas makes them hard to start. If the car had been sitting for a year or more, get the old gas out of the tank and put in fresh. There is a drain plug on the bottom of the gas tank.