I've been having this issue where my car is really slow to crank, but only when it's warm. When it's been sitting a while and is cold, it fires right up (even in very low temperatures). If the car is at operating temperature, I turn it off, I can turn it back on with no problem.

However if I let the car sit for about an hour or so and come back, then the car takes 3-4 seconds to start up. The battery is good and the starter sounds strong (it's turning over the motor just fine), it's just that the engine doesn't want to fire. The past week or so I've really wondered whether the car was going to start or not. It always has, but I'm worried it's going to leave me stranded one day.

A couple observations. This slow crank phenomenon has primarily occurred after short drives (8 miles or so). The car reaches full operating temperature during these drives, but they are still relatively brief. I also have an Evans E-Tune, which may or may not be contributing to the problem. I really don't know.


Any idea what is going on here?

 

Hey dude. Trust me on this one, it's the battery. I had the same EXACT symptoms (I am stock). It went on like this for a good few months. Maybe a little more. It kept getting worse and worse until one day I drove to a store, went in for <10 minutes, got back in the car and it would not crank. There was no power left in the battery.

I got a jump start and headed straight to the Honda dealer down the street. They replaced the battery and have not had a single problem since. Same situations as you, even times when I stopped for gas. If the car was sitting longer, say over 45 minutes, it would usually crank. Change out your battery and you should be good! Good luck.

 

I was having a similar problem last summer intermittently and I went by the Honda dealership to have them check the battery. They said the battery was good - in fact they installed the battery themselves about two years ago. It should have plenty of life left.

I'm not entirely ruling out the battery at this point, it just seems improbable. How old was your battery when you were having problems?

 

That's the thing, I'm not really sure. It was the battery in the car when I purchased it. I wanna say it was not the OEM battery but I can't be 100% sure about that. If it was changed at some point, it didn't last very long. Car is a 2007. So say the OEM battery lasted 4 years and the owner changed it before I bought it sometime in early 2011, or even 2010 just to be safe, I had to change it this past January. So it didn't last too long.

Is there any way you can check?

 

I agree that it may be your battery. What is the CCA (Cold Cranking Amp) rating on it? Also, are you letting the fuel pump prime all the way when turning ACC on? Sometimes I let it prime twice to make sure the fuel rail has proper pressure.

 

You're using the wrong terminology. Your engine is "cranking" just fine. The statement I quoted from you just said so. It's slow to "fire". That's a whole other situation. It's not your battery. It's not your starter.
Look into the possibility that your engine is slightly flooded when you do a re-start when "warm". How do you do the start seqence? Do you touch the gas pedal during this sequence as a routine or habit? You should not be anywhere near the gas pedal during the start up period till the engine is running and idling in a stable way on its own. If you are already doing this, then it's possible that your injectors are not closing fully at the end of each cycle and when you shut down, gas continues to dribble into the cylinder. An hour or so may not be long enough to dry things out. After the engine is hot, the fuel vapour consistency from a dribble is much different than when the engine is not hot enough to take care of it. Parking overnight and then doing a cold start will generally take care of a slightly flooded engine from the last shut down. People who have cars that "normally" flood, know that if they just go away and come back much later, it'll usually start right up.
You may also want to check or replace the sparkplugs. Check the IAC (Idle Air Control) system. Check air filter. Are you using the right type of fuel? Is the car modded or altered in any way?

 

This is a good point from xviper. When I'm in the situation of a quick stop and shutdown, such as getting gas or running into the store for a few minutes, I hit the starter button almost immediately switching on the ignition. When the car is cold, I'll let the injectors go through their quick priming cycle before I start it up. I may be way off on this but pressing the button immediately in those stop-go situation seemed to help a bit. Until my battery shit the bed.

 

It could very well be that the engine is slightly flooding, like you mention. I'm going to take the car to the dealership tomorrow and they're going to do a battery diagnostic test to see if that's the problem. If not, then we'll have to try something else.

 

I just noticed this in the OP's sig ..................
AEM V2 CAI, 70mm Berk HFC, Invidia Q300 dual exhaust.
Flash Pro + Evans E-tune.
Any or all of these things could contribute to further aggravate the situation. Unless the car has been tuned on a dyno and all operational parameters are properly mapped out and tuned, there may be properties of the tune that can lead to a difficult warm start. Partial flooding could be a consideration, as is the opposite (lack of fuel).

 

That could very well be. However I ran the tune for nearly a year with no problems at all.