My 5th gen prelude has a hard time starting first thing in the morning or after being turned off for more then 20 minutes. Basically the car will take 5-10 second of cranking followed by a quick shudder and then runs normal. No CEL and the car runs perfect once I get past starting it. If I restart the car in less then 20 minutes after turning it off it starts fine, only when it sits for a while. I replaced ignition coil, plugs, wires, cap, rotor, fuel pump and the problem still persists. Any ideas?

 

possible fpr leaking into vacuum hose ... possible ignitor heatsoak

 

Is it cranking slowly or at normal speed? Could be as simple as a dying battery.

 

cranks normal. Battery and starter are new. I ran into an overheating issues yesterday and after I replaced the thermostat and radiator cap not only did my overheating stopped but my starting issue went away as well. We will see if it lasts. I find this really weird as neither of those parts have anything to do with how the car starts.

 

Actually the temp sensors can cause issues. Do you have any Check Engine codes, or a Check Engine light on?

I ask since my car would have random issues, and I traced it to a temp sensor on the head. Problem was, my CEL was not working, so I had no idea. Only found it by plugging in another ecu so that the CEL worked.

 

My CEL is on but its for an egr valve. I cleaned it twice and is still triggers it. We dont have smog or inspection here in Miami so I can live with it, at least for now. No other cel then that. I didnt really bother to look at sensor, I should have at least cleaned it but this was more of a parking lot repair then anything else. My thermostat was stuck.

 

test the engine coolant temperature sensor for ohms across the pins ... should be 2000-2500 ohms when the car is completely cold and 180-250 ohms when the car is completely warmed up

it's the two pin sensor under the distributor