Cold Starting

[ExSport]

This morning, it was quite cold (-20C/-4F). I went out to start my explorer a few minutes early to warm up a bit. It started normally, idled for a couple seconds at approx 2000 RPM, then dropped off to under 1000 and died.

I re-started, and so long as I kept my foot on the gas, it ran. But if I let off, it would die again.

I finally left it, and went back inside for about 5 minutes. When I came back out, it started and ran smoothly at about 1000 RPM, and so off to work I went.

So, my questions... under cold starting conditions, shouldn't the engine "race" for a while at 2000 RPM or so and slowly drop back to normal idle speeds? And if so, what would keep it from doing this? How does this function work? Is there a sensor or something that tells the computer to deliver more fuel until it gets to a certain temperature?

If I understand how it all works, maybe I can figure out why something went wrong.


Thanks!
Brian

 

[mrboyle]

It was most likely just cold. I mean how would you react after sitting outside at -4 all night. So long as it continues to work fine leave it be.

 

[rpenner54]

Do you have a block heater? If not you should look into getting one. That would probably help these situations out a little. Yes you are right it should float at higher RPM's untill it warms up enough to move itself down.

 

[ExSport]

I wouldn't really say it works fine. Sure, it doesn't have any problem starting, but something is not telling the engine to keep the revs up. Even our 93 Geo Metro will idle (race) on its own in these temperatures!

I was thinking of getting a remote starter installed. But if the engine quits, there's no sense.

I will try the block heater, but I'm afraid there is a problem else where.

Thanks for the replies.


Brian

 

[shooter_1000]

Your symptoms sound exactly like my brothers Windstar had. After browsing around this site, I found a thread that gave some help. It talked about the IAC module (Idle Air Control), if you locate it on the throttle body and remove it and clean it, you will likley find that your vehicle will start and run fine when it is cold.

The IAC is a variable orfice mounted on the throttle body, between the throttle butterfly and the intake manifold. When your throttle butterfly is completely closed, this module controls the amount of air that enters the engine by varying the size of the opening. The computer controls the fuel injectors, so only the air needs a passage and regulating when the butterfly is closed and the computer controls the amount of air through this module.

I have a 4.0L OHV in mine, and the IAC is located on the drivers side of the throttle body. It is a black cylindrical looking thing about 4 inches long, with and aluminum block at the end that it is mounted by.

When mine is cold, and I mean cold, there are times when I have no choice but to leave it outside and not plug in the block heater overnight at temperatures colder then -30, it starts just fine in the morning. When it is started cold, it revs up to about 1600rpm or so and then slowly backs down to about 1000rpm untill it is warmed up.

Go and check out this thread,

http://www.explorerforum.com/forums/showthread.php?threadid=23885

They also say it is only a temporary fix, the cleaning it, but my brothers is still fine after 2 months.

Good Luck, I hope this helps.