I have a 1999 honda accord DX with auto trans. the car does not want to start after it's sat overnight. When turning it over it turns over for a second then nothing! starts fine when it's been drove and warmed up. Seems to me any problem would happen wend the car would be hot not cold? The car has a new battery. Also trying to jump start the car when cold does not help at all. Oh and the car only has 138,000 miles on it.

 

Main-Relay

 

My understanding main relay is a hot starting problem mine is a cold starting problem. by thinks for trying to help

 

When you try to jump start it are you using a HOT wire from starter directly to the battery? First thing you want to do is determine what you're missing when it won't start.

Testing:
1) Make sure there is spark coming from the ignition wires, if pass continue
2) Run a hot wire from starter to the battery, if it cranks but does not start it is not a starter issue. Put a test light on the end of the starter wire and hit the ignition switch on. Is there power? If not it's an ignition switch issue.
3) Crack a fuel line loose, turn key to on position. Does fuel shoot out? If not then you either have a clogged fuel filter or bad Fuel pump.
4) Is the Catalytic converter clogged? Usually when the vehicle gets hot it will stall or cause a no-start issue if the catalytic is clogged. disconnect heater bolts and try to start it.

thats just a few ideas to start

 

if it were me id take the starter out and go to oriellys and have the test it