2003 S2000 85k, Stalls after no previous issues

[BegleyN]

http://forums.s2kca.com/showthread.php?t=27347

All,

I found the above thread and have tried driving my vehicle without freewheeling, but I have been unable to keep my S2000 from immediately stalling after coming to a FULL STOP. I can restart immediately and the car will idle without any issues. I can also let the car drive at 1 MPH and less than 1,000 RPM and it will idle smoothly without any issues all day long.

I have always used the power-train to slow my cars down, but it does feel unnatural to hold the gear all the way down to 1,000 RPM.

Other tidbits -

There were no problems before yesterday.
It is very cold (single digits at night / highs in the 30s)
I was very hopeful using the suggested driving methods from the thread referenced above, but it did not seem to help after several attempts.

Is there anything I should be looking for outside of driving methods? It seems odd for this to never ever happen and now it happens every time I come to a full stop.

Thank you for helping out a first time poster!

[camoy]

When you restart the car after the stall does it turn over pretty quick or does it turn over slowly? When you started it the last time and it was really cold, did it crank over slowly? I ask as you don't freewheel, and you state you started having the problem after the very cold weather. What you could be seeing is a weak battery that is getting ready to go out. I am not sure about the S2000 but I do know many of the newer cars now will not run without a battery. And this could be what you are seeing with the car shutting off, once the alternator spins down, maybe the battery is not showing enough of a voltage to keep the car happy and running so it shuts of. Just my guess though I am sure Dave will have a better response.

[BegleyN]

The battery has been turning the engine with ease, but I will pay attention once I go to start it later today.

[Chickwithastick]

My car still dies sometimes after having the stalling/idle dip/stuttering issue. I changed my driving habits to hold all the way down to 1000, and I have noticed it will still have problems when the weather changes, but no where near what it was doing before. I have just learned to deal with it.

I'm wondering if our AP1 ECUs are just more sensitive?

[repiv]

If you are holding gear as long as possible and you still have problems with the engine dying, then as I may have hinted in my "Tip of the Day", it's time to look at maintenance items. Shortcomings here will be a detriment to an engine management system that is trying its best to keep the engine from dying. Here are some points to look over:
-air filter
-sparkplug condition and gap and type
-quality of fuel and the possibility of water build up in the fuel ...................... try some gasline antifreeze and/or octane boost. Even if you aren't cold enough to freeze water in the fuel lines, gasline antifreeze will help nullify the affects of the water. As it gets cooler and particularly if you are in the habit of running your fuel tank very low before fueling up, you can get a lot of condensation buildup in the tank. This falls out of the air and becomes water in the fuel.
-injectors that have never seen any kind of cleaning maintenance
-dirty MAP sensor passage way in the throttle body
-dirty Idle Air Control air passageway
-really badly clogged fuel filter sock due to dirty gas one time too many
-excessive slack or too tight throttle cable (DBW exempt).

[BegleyN]

It seems to have cleared up. Maybe the method prescribed in the original thread just needed a few more reps. Thanks for the help.

[repiv]

I think one must be consistent. I've personally found that when I get remiss or lazy and don't "hold gear" just a time or two, the idle will waver when stopping. If the state of my car's maintenance were somewhat wanting, surely it would die on those occasions. This is a particularly finicky car indeed.