zeroptzero

For pretty much the entire driving season this year I've noticed that my car is hard to start after it has been sitting for a few days in my garage. I only drive it on weekends and between drives it is hard to start up. I've tried to hold the start button a bit longer which helps a small bit, but still not perfect. After I get it started once it is fine all day long and starts really quick on subsequent starts. The battery, coils, starter, injectors are pretty much new. The engine turns over fine it just takes a long time to catch and fire up, and for the first couple of seconds it sputters and comes close to stalling out. If it does stall out then it fires right up on the second attempt without issue. To lessen the stress on the thrust bearings I've disconnected my clutch switch, so I start the car with the clutch engaged and the shifter in neutral. I don't know if that adds extra load to the start procedure, temps go down to maybe 40 degrees F at night the last month or so. I have a fuel pressure gauge and I know the fuel pressure is pretty much zero after the car has been sitting for a few days, but it goes right up to spec as soon as the fuel pump initializes. Thanks for reading, any opinions would be appreciated.

sillyboybmxer

mine has always done that too
just thought it was the way the s2000 was.

zeroptzero

Thanks for the reply, mine only started this season, and I've been using it the same way for a number of years. It's not a big deal but I just noticed a difference and wondered if it related to any specific part.

preludepatrick

I start mine every 2 weeks or so and I never have issues starting. Idle may dip a bit for a few seconds but that's about it

starchland

Mileage? Iacv clean

zeroptzero

Mileage since we rebuilt the motor is about 5,000 kms. I cleaned the IACV about a year ago, my idle is rock solid once the engine starts. MAP sensor is new, new air filter, I have replaced most engine parts with new or low mileage equivalents within the last year. I drove the car yesterday and I will try to start it up today to see how long of an interval it takes to cause the rough start since it doesn't happen when the car is in regular use.

zeroptzero

I started the car this morning as a test 24 hours after I last ran it, and it started up perfectly. Fuel pressure was down to 0 psi prior to the fuel pump initializing, and about 43psi after the pump activates, similar to past starts, so I don't think it is related to fuel pressure. So it appears that the hard starting is worse after longer periods of sitting, beyond 24 hours and up to 7 days.

starchland

any updates?

S2Kennyy

i have the same, after 2+ days sitting stil the engine starts a little rougher.

zeroptzero

I have noticed that the engine will fire up quicker if I give it some throttle during the crank sequence, easy enough to do but I've never had to do that in the past.

Too many new or clean parts on the car to isolate it to one thing. Starting the car within a 24 hour period is perfectly fine, it only exhibits the odd behaviour after 2+ days of sitting.