I use my S2000 as a weekend toy/track car. At my last event out of the blue the car took an extra 6-7 cranks to start and shot out smoke. After the car starts and stumbles for a bit, the car works perfectly, no check engine light, no loss of power anywhere.

When I got back from the event I did a compression check to see if anything was abnormal and all cylinders were 235-240 psi. While I had the spark plugs out I put new OEM NGK plugs in there. Did not seem to make a difference.

I drove my car to work one day and noticed a distinct smell of raw fuel after the car started. Then I thought back and the last thing I did was put in a fuel tank baffle plate a couple track days before I had the issue. Maybe I didn't click the fuel lines into place and they are leaking and not providing enough fuel pressure when starting? Checked that and nope the lines are tight, no leaks. Must be the smell of unburnt fuel in the exhaust from not starting.

Not sure where to go from here, I wanted to check fuel pressure because it seemed that when I prime the fuel pump a few times with the key it starts okay. That does not seem to be the case though must have just gotten lucky on a few starts.Seems to be worse on "cold" starts. Usually when I shut the car off and immediately restart it does fine.

Any suggestions?

Here is a video, ignore the screech from the starter not disengaging the flywheel I know about that,

 

lamda replacement time

 

Oxygen sensor? Would that be the cause of a hard starting problem which the car operates normally after starting (and stumbling for a couple of seconds) with no check engine light?

 

Shot out smoke? Possible leaking injector causing a flooded condition

 

Just wanted to post the solution to my problem so this thread had a resolution.

For anyone having hard starting issues check out this youtube video to see if your fuel pressure regulator is leaking past the internal seal and "flooding the engine" during restarts.

I've had this issue continuing to get worst for almost 3 years. It started as seeming like a hot restart issue then became a hard start no matter what condition (sometimes up to 10 seconds of cranking). In trying to diagonse the issue I adjusted valve clearance, replaced spark plugs and fuel pump, cleaned MAP, cleaned IACV, tested and cleaned fuel injectors, and swapped ignition coils. Probably even more stuff I am forgetting. I even tested fuel pressure with special Honda gauge and it passed the FSM tests and held fuel pressure very constant when primed which lead me away from the FPR. I happend to stumble across the video below in my deseparate search to find a solution. I'm so thankful I did because now my car starts perfectly and it was such a simple fix.

BTW, for anyone looking to replace their FPR I bought GP Sorensen P/N 800-483 with free overnight shipping with 20% off from a well known auto parts store and it was the exact same as OEM. Made in Japan same casting marks on the body etc.