'95 Honda Civic DX, 142K mi

Cranks but will not start, only when cold (< 50F). Repeatable problem. Car runs perfect once it starts.

Tests done when not starting:
Spark is OK.
Fuel pressure on FI rail is OK.
5V on MAP sensor.
Main relay clicks good, fuel pump hums nicely.

Work I've already done:
New ignition coil
New igniter module
New fuel filter
New battery
Resoldered main relay connections
Cleaned ground connection on thermostat housing

Once it warms up in the afternoon, car starts immediately. Never stalls -- runs great. Dead as a door nail the next morning, if cold. No CEL, no diagnostic codes found.

Any help is appreciated!

 

I'm no Guru, but you might want to check the Fast Idle Valve:

 

Thanks for posting that -- I'll check it out!

 

+1 to the fast idle valve "(IACV)"

also you could test out the coolant temp sensor...

 

Iknow you say spark is o.k but check out the cap and rotor for carbon pile up and cold enough temps it could be enough resistance not to start